# Building Harold Hall's Simple Grinding Rest



## stioc

Starting this build thread to ask questions as well as help out anyone else out who might be thinking of building one. If you don't know who Harold Hall is, do a google search but he's an author of several machinist books and has a reputation for being a pretty smart fellow. He also has a youtube channel with a few videos.

Here's the link to his page about this particular project:






						Grinding Rest, Simple
					

Design for, and method of making, a Simple Grinding Rest




					www.homews.co.uk
				




The grinding rest is in his book about Tool & Cutter Sharpening, fantastic book btw and I highly encourage a hobbyist to purchase one. It's only about $10 and the info was well worth it if you have any interest in keeping tools sharp. He has two designs of this rest; a simple rest and an advanced rest. This build is for the simple rest.







I chose the simple rest because well I figured it would take me less time to build and I won't lose my focus/motivation - which tends to happen to me on long projects. BTW, this gentleman did a great job documenting his build and that actually motivated me to make this project: 






						Learners Project - Simple Grinding Rest
					

Next little project that should result in a nice usable tool and progress general machining experience.  So the game plan is take these blanks   and turn them into this simple grinder rest as designed by Harold Hall (http://www.homews.co.uk/page146.html)    As you can see from the...




					www.homemodelenginemachinist.com
				




After reviewing the design in Harold's book several times I became comfortable with what each part does. The next challenge was converting the metric measurements to the US measurements. This including the stock thickness he is using as well as all the screws, fastners, taps etc.

Lastly, it was time to go shopping for the stock (primarily 1018 cold rolled), nuts and bolts etc that I did't have on hand. I also purchased a couple of tools that I thought would make my life easier. This included a 60 deg dovetail cutter, a couple of YG1 brand spiral flute bottom taps.

Here's the stock I purchased and the bolt holes etc that I decided to standardize on. I won't provide any spacing dimensions etc beyond the rough sizes because all that is in the book - in other words buy Harold's book if you want to build this


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## stioc

*Day 1:*
I rough cut almost all flat stock on my bandsaw to size in mm using my digital vernier calipers (which measures in mm, fraction and decimal and converts between them pretty easily). I rough cut a few mm over to account for blade thickness and tracking sideways. Between measuring and cutting the pieces it took about an hr.






After that I spent another couple of hrs squaring the pieces up to their final dimensions (in mm)


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## stioc

*Day 2:*
So far so good! Now that the stock is ready we can start machining. However, while I could've drawn this up and done it using CNC I decided to do this the old fashion way -well sort of, more on this later. I Dykem'd the pieces and did the layout work first.






Harold suggests this a relatively simple project for a 'lathe only' shop. He does recommend a drill press though. Now, I'm not a very experienced machinist by any imagination but I think without a mill with a DRO (CNC in my case) it would've taken me a long time to make. I highly recommend a mill with a DRO so that once you find the edge of a piece you can just move to various locations to drill holes, tap etc. Speaking of that:

STIOC's tip: I highly recommend some sort of a work-stop to make things go faster without having to find your x0y0 again and again. I also suggest making your x0y0 along the fixed jaw of your vise so that it stays constant even as the size of the stock pieces change. I realized this after I was 50% through the project lol I made mine top left and used a work stop.

OK on with the machining already. I decided to build it from the bottom up...the reason for me was because machining is one of many hobbies I have and the base pieces are relatively simple. So they serve as sort of a warm up, getting to learn my machines again etc. So I started with the angle base...since this is A36 which can be hard on HSS endmills I chain drilled it first and then created a slot.











The slot was supposed to be 1/4" (6mm) but since I drilled it with a 1/4" drill bit it took me a few passes with the 1/4" endmill to clean up the slot and in reality the slot ended up being closer to 3/8". This is what I meant by starting with simpler things to warm up lol. Thankfully this slot size is not critical as long as I drill the vertical piece's hole centered to this slot and use the correct fastner.

STIOC's tip: drill with a size or two smaller than the endmill itself if you don't want to oversize the slot.

The next piece, the vertical bar, is basically the same thing - a slot and a hole except I didn't chain drill since this is 1018 not A36. I only drilled a starting hole for the endmill since drilling is hard on endmills.

After that I made the height adjuster. This has 3 of countersink holes (one of these is from the back side btw) and then a large 30 deg countersink to serve as a ball seat. This 30 deg is tricky for a few reasons:

1. One your lathe has to be able to swing an almost 115mm length. I had to shorten the length off about 1/4" as I was literally a paper thickness or so away from hitting my lathe ways and I didn't want to convert it into a permanent gap-bed lathe. 

2. I couldn't figure out a way to clamp this piece in a 4-jaw chuck either. So I had to use the face plate and think clamps. My clamp set for the mill were just too bulky and big.

3. The angle and size are somewhat critical. Lastly you have to center the work which doesn't have to be super precise...





















It was definitely a pucker moment in case the setup slipped but 120RPM, .005" cuts and lots of patience won this game. Now I have to make another one to match...


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## Technical Ted

Here's a link to my post that shows more of the accessories that go along with the rest. I also built the advanced rest which I found much easier to setup, but they both work fine. Now I have a KO Lee tool and cutter grinder so they don't get much use, but they were very nice and fun projects to make. 









						Harold Hall simple grinding rest
					

Just finished phase I of making Harold Hall's simple grinding rest... Drew it up in Fusion 360 first and converted it to inch units from metric. Now, to buy a dedicated bench grinder and make the required accessories for tool holding and end mill sharpening and get everything set up and...




					www.hobby-machinist.com
				












						Harold Hall advanced grinding rest
					

Although I just recently finished up his simple grinding rest, I decided to make the advance rest now. Two reasons: 1) I really like the simple one and the capabilities that it has, but know that the advanced rest would be easier to set angles and be a little nicer to use. 2) I was looking for a...




					www.hobby-machinist.com
				




Nice detailed post. Have fun!

Ted


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## Jubil

Great write up and good, clear photos.
I also built the simple rest. I really like it, though it seems a little small and delicate. Very interesting project. I was thinking of building another one and scaling it up a mite. Probably won't get much use, except for hogging off,  because I have a t&c grinder. But I can see it being used for grinding things other than cutting tools.
Thanks for posting. 
Chuck


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## stioc

Thanks gentlemen! I see you guys eventually moved on to the big-boy toys with your T&C grinders. I've had my eyes on the Chinese Deckyl clones but can't find the 5c version for under $500. However, being a minimalist at heart I figured this tool rest should function well for my needs. As for the accessories my plan is to build none because:

1. I have 5c collet blocks, square and hex to hold end mills and such in those.
2. I have a Phase 2 end mill grinder to grind the sides of the endmills
3. I have a Drill Dr 750X for grinding the drill bit ends
4. I can use my original lathe toolpost (the non-quick change type) or even the AXA tool holders to hold the tool bits

Again this is just my thinking, once I build it and try these accessories with it I may or may not change these statements


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## stioc

*Day 3:*

Today was the day to hopefully finish the base and in my mind the first 30% of the project (dovetails being another 20%, table being 25% and the leadscrews being the final 25%).

So today included making the second piece, the head clamp and the clamp spacer. The head clamp requires a few holes and a matching ball seat. This piece (no through hole on this one but I drilled it part way) is smaller and on the contrary required more careful clamping because the clamping similar to the first one shifted when I tried to take a cut. I rearranged it such that it's 'boxed in' and not just clamped down. This worked and the piece was completed.






The clamp spacer has to be measured for distance before cutting, truing and then two #6-32 holes drilled and tapped. This completed the base.


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## brino

Great write-up and photos.
I am "Watching".



Thanks for sharing this!
-brino


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## Janderso

So that's how you do it.
Well done! Great thread and well documented.


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## Technical Ted

Just a note... you don't need a dovetail cutter, as you listed in your shopping list post, to cut the pieces that make up the dovetail (if you follow Harold's drawings anyways). Just tilt the pieces at the correct angle and use an end mill or whatever. 

But, you can use a dovetail cutter if you so choose, but I'd save the cutter for when you want to make Harold's advanced grinding rest.   

Ted


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## stioc

brino said:


> Great write-up and photos.
> I am "Watching".
> 
> Thanks for sharing this!
> -brino





Janderso said:


> So that's how you do it.
> Well done! Great thread and well documented.



Thanks for following along! I hope it's helpful to anyone else considering building one because I certainly had a lot of figuring out to do on how to approach the whole metric vs. imperial deal while still following along the drawings. Also Mr. Hall (who btw is 86 yo now as of 2019!) doesn't do much hand holding in his style of writing. He does provide a few helpful tips on the tricky bits but that's about it- I must admit though that it actually makes the project more fun and rewarding!



Technical Ted said:


> Just a note... you don't need a dovetail cutter, as you listed in your shopping list post, to cut the pieces that make up the dovetail (if you follow Harold's drawings anyways). Just tilt the pieces at the correct angle and use an end mill or whatever.
> 
> But, you can use a dovetail cutter if you so choose, but I'd save the cutter for when you want to make Harold's advanced grinding rest.
> 
> Ted



Funny you mention that because guess what I was just working on? Making sure my math/plans line up.  Certainly not necessary but I'm nowhere near my shop and had some time during lunch - gotta make progress even if it's virtually lol







You're absolutely right about the dovetail cutter though. I just thought it would make things easier and I only need a hint of an excuse to buy more tooling!


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## stioc

*Day 4:*

So now that the base is built. I can get into the fun part of this project i.e. the dovetail slide that moves the table in and out like the crossfeed of the compound. I started modeling the dovetail slide to make sure my dimensions in imperial are in check (they're not critical as long as the angle is exactly the same for both the inner and outer dovetails. This is where the dovetail cutter is so much easier and accurate.

However, before cutting the dovetails I decided to drill and tape all the holes in the dovetail parts first. This is where doing a little bit of calculation up front helped me out and I simply issued a few CNC G90 G0 x/y commands to drill all the holes in the exact same locations with the help of a work stop. Also glad I did the layout work because twice I issued the G90 commands and noticed the location was off compared to the layout because I messed up my calculations.





















While waiting for the spiral flute YG1 tap I've been using the 1/4-20 tap (with much trepidation) from my cheap Harbor Freight set I've had for 5 yrs - I think I paid $40 for it and have used it many times but mostly in aluminum. It's worked fine so far even in this 1018 steel.






After all the drilling and tapping I located one of the parts on the vise to cut the dovetail. Mounted up the dovetail and realized I couldn't line it up right. I know I ordered a 3/4"x3/8" from All Industrial. Checked the stamping on the dovetail shank, it said 3/4 x 3/8 x 5/16 -ugh! the height is 5/16 not 3/8. I wasn't happy. I think @Technical Ted Ted jinxed me - I kid I kid LOL. This means doing it the manual way, which requires more setup time and more chance of error from not having repeatability. So my option was to order another dovetail and wait 2 days or forge ahead.
To be continued...


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## stioc

*Day 5*

Well patience is not my strong suit so onward we go. I used an angle block to carefully set the angle and then checked/tweaked it as needed. This was repeated each time for four dovetails, it really wasn't bad, thanks to the 60 deg angle block.











This is the inner block that requires reverse dovetails on both sides.





Double checking the direction of the dovetails





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Honed all the edges





Everything fits





This is all the progress I've made thus far and it has gone pretty smoothly without me messing up parts and having to redo stuff. Still have lots of other pieces to do; namely bearing blocks, table, fence carrier, fence, leadscrews, handwheels...


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## stioc

*Day 6*

Continuing where I left off last.

Made three identical bearing blocks:





Then started on the fence carrier but it's been kicking my @ss. It's like a T-nut with threaded holes on top as well as a hole running the entire width with the center portion threaded. The first attempt (shown on top) looks good with all the features but I went a few thou too deep on one of the slots - this will make it not sit flush.






So I had to scrap it and start over (cut another chunk of steel, machine it to dimension and then drill and thread)...it was going well






until the corn-cob endmill took a sudden bite...son of a #@$! I guess I got too greedy with my WOC at the DOC even though my feed rate was about half of what it should've been. 






So I guess it'll be take 3 next time :lol_hitti So far I hadn't ruined any parts so this was the first. Also when I start to bolt these pieces down to the rest's top plate everything needs to align correctly, there's really no room for making imprecise holes etc. It's making me a bit nervous.


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## mattthemuppet2

bummer! Looks like you were climb cutting - my guess is that there was a bit of slack in your table travel and the cutter self-fed itself a bigger bite than you expected. Try cutting the other direction next time and leave the climb cutting for a finishing pass with a nice 4 flute.


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## stioc

You're 100% correct. I was indeed climb milling as I often do due to the fact that it creates less strain on the machine and the cutter. In this case, after retracing my steps from last night, I was in the cut when I accidentally hit the key to reverse direction. The CNC software is configured to take up the backlash amount on directional changes and that's when the cutter took a big bite.


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## mattthemuppet2

I'm sorry, I didn't realise that it was on a CNC, that changes things a bunch. Glad you figured it out.


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## stioc

*Day 7*

I did remachine the fence carrier block but didn't drill and tap the top 4 holes nor did I skim it flush with the top plate. Doing so at the very end will be better in my opinion.

Next I started mounting all the pieces to the top plate. This is sort of the moment of truth. If things don't line up that would be a bummer. I decided to start with the table's fine feed bearing block, these are all going to be #6-32 holes, the drilling and tapping is in the 1/4" thick plate but these are no through holes so the depth has to be controlled. Also need a plug tap, and I highly recommend the YG1 spiral tap I got, it cut like butter and evacuated the chips up like a drill bit does.






With the first bearing block in place I attached the center dovetail and then placed one of the side dovetails against it, making sure it was all square to each other. 






Then came the second dovetail. I decided to fold paper 3 times and use that to leave a gap because the two dovetails were running a bit rough against each other. However, in hindsight I should've just made the holes in the two end dovetail blocks slightly larger to allow small adjustments and I should've done the same for the bearing blocks too...I actually did in the end because things were binding up.











This completed most of rest's top and the milling work. I still have to make a fence but next I want to start on the round/lathe parts.


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## stioc

*Day 8 (the lathe work):*

Well I thought this was going to be somewhat of a more difficult task to turn leadscrews and graduated dials but I was done in 4 hrs and actually really enjoyed it. I just seem to enjoy the lathe work more than the mill work it seems lol






Used the tailstock die holder for the first time. This thing is slick but I was turning by hand so it was a slow going





For the longer leadscrew after I got 5 or 6 threads by turning it manually I decided to speed it up...to 600 RPM by gripping the die stock holder and hitting the switch (making sure I was clear of everything and I had an exit strategy if things went sideways). I don't recommend this if your lathe has a powerful motor or you're cutting a 'stronger' thread. I had purposefully undersized the major diameter by .01" so it threads easily and I can actually stall out the motor on my lathe with my hulk grip (the belt slips). This worked so well, how well? literally 3 seconds and I was done!






Then I made graduated dials, each line is .0013"






There's everything completed...I can see the light at the end of the tunnel now!


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## stioc

Removed the dykem and honed the sharp edges of all the parts. Ready for assembly!


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## stioc

*Day 10*

The build of the rest is finally complete. I wouldn't call this project difficult but it took some time (and dedication) because it does have quite a lot of parts. While I had studied it well before starting and made sure I had tools, supplies etc ahead of time to carry out the project but I realized during the project that a few handy jigs and tools would've helped even more. One of the things I want to make is a better work stop, a AXA holder for the dial indicator (for doing 2nd ops, sometimes you can't avoid this) and add air to the lathe because it works so well on the mill. A vfd on the mill would be sweet...but I need to research what motor will fit my RF30, maybe replace the spindle bearings too.












First task was to true up my 10 yr old grinding wheel which I didn't realize how irregular it was until I did this






This was very dusty work and I should have done it outside. Even with the vacuum on this accumulated on the grinder cart:











Then I attempted to sharpen an endmill...which has a learning curve to understand all the angles and such so that will take some learning and practicing...now that I have the ability to do so in my shop.


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## ttabbal

Nice! I'm eyeballing the advanced rest, but it will be a while before I can get to it.


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## stioc

The advanced rest looks to be easier to adjust and use so it's a couple of steps above this one for sure. However, I figured it would take me longer to make too. I haven't yet had time to use this one properly but I think this will do ok for my current needs until I decide to get a real tool bit grinder.


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## pontiac428

Nice work!  That is a lot of parts.  The rest looks very functional.

Keep resharpening that end mill.  See how it cuts.  Repeat.  Grind it down to a nub.  Once you find the right angles and timing of the flutes (just like a drill bit, only more steps) you'll be able to grind one in your sleep.  You might want a good tool grinding wheel (Norton 38A 60-grit) for a better finish and to keep from heating up the HSS.  Post up what you grind!


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## stioc

pontiac428 said:


> Nice work!  That is a lot of parts.  The rest looks very functional.
> 
> Keep resharpening that end mill.  See how it cuts.  Repeat.  Grind it down to a nub.  Once you find the right angles and timing of the flutes (just like a drill bit, only more steps) you'll be able to grind one in your sleep.  You might want a good tool grinding wheel (Norton 38A 60-grit) for a better finish and to keep from heating up the HSS.  Post up what you grind!



Harold's grinding book covers lots of details which prior to making the rest were hard to visualize (I'm a visual person) but I think rereading those will make more sense. I just need more seat time 

Thanks for the wheel suggestion! I'm thinking about make an arbor adapter and getting one of those fancy cup wheels...thoughts?


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## pontiac428

stioc said:


> Thanks for the wheel suggestion! I'm thinking about make an arbor adapter and getting one of those fancy cup wheels...thoughts?



A cup wheel is necessary to grind a flat using proper technique.  The dressed surface of a conventional wheel presents a curve to the work.  With a cup wheel, you can set up the grinder and rest like a Delta carbide grinder with the rest on the side.  A flared wheel will give you an easier time with 4-flute end mills, but aren't great for lathe bits compared to a cup wheel.  A bench grinder is made for 6" wheels direct drive, and a tool grinder is made for 4" wheels belt drive, so your surface speed may be slow with the smaller wheel.  Cups and flares come in 5", too.  You'll have to see what works.


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## Technical Ted

Go here for Harold's website. Check the videos... he has them on using the grinding fixtures for grinding end mills and other tools. Lots of stuff on his site:






						My metalworking and other interests. Harold Hall
					

Introduction to my many hobbies and other interests, particularly, metalworking in the home metalworking workshop.




					www.homews.co.uk
				




Ted


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## HBilly1022

If you want to sharpen the "ends" of your end mills you should make Howard's end mill sharpener http://homews.co.uk/page121.html. I made one and it works awesome. I've used mine a LOT with very good results. I'm a real HH fan and have made quite a few of his devices and purchased all of his machining books.


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## stioc

So the other day I decided to give the grinding rest a try using a wood chisel as my test subject. The end on it is pretty well chewed up and rough.






I started by getting the end nice and square and that worked better than I expected





Next I set the angle using a 30deg angle block against the fence. The idea is to maintain the angle and feed the chisel straight while also keeping contact with the side of the wheel. One of those moments you need a third and a fourth hand.






The results were ok but not great, one end of the edge was sharper than the other. I didn't take a pic. However, despite my wishful thinking that I was done with the rest this made it pretty obvious to me that in order to take advantage of this rest I really need to make a couple of accessories for it also.

So, I started with the swivel plate because it forms the basis for several other tool holder accessories.


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## pontiac428

Time to get yourself a cup wheel.  Dressed surfaces do so much better than the sides of a standard wheel.  Set up that rest to work like this pic, and you've really got something:


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## mattthemuppet2

lovely work, I keep meaning to make a better rest for my grinder too. I second the suggestion for a better wheel. If you can get 2 wheels a 30 to 60 grit for roughing/ shaping and a 100 grit for finishing will work well. I only have 1 grinding wheel on mine, so went with a 100 grit Norton wheel and it works very well. I can always use an angle grinder for shaping 

Also, chisels are often ground using the end of the wheel, holding the chisel at the top. That gives a hollow grind that works well with chisels. Grinding on the side will give you a flat grind, which is stronger but you won't be able to get it as sharp.


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## stioc

pontiac428 said:


> Time to get yourself a cup wheel.  Dressed surfaces do so much better than the sides of a standard wheel.  Set up that rest to work like this pic, and you've really got something:






mattthemuppet2 said:


> lovely work, I keep meaning to make a better rest for my grinder too. I second the suggestion for a better wheel. If you can get 2 wheels a 30 to 60 grit for roughing/ shaping and a 100 grit for finishing will work well. I only have 1 grinding wheel on mine, so went with a 100 grit Norton wheel and it works very well. I can always use an angle grinder for shaping
> 
> Also, chisels are often ground using the end of the wheel, holding the chisel at the top. That gives a hollow grind that works well with chisels. Grinding on the side will give you a flat grind, which is stronger but you won't be able to get it as sharp.



Thanks guys. I'm a total grinding newbie so I'm just soaking up all the feedback. Sounds like a cup wheel will be more useful (than say a flared or these disc wheels)? Is there any reason to even have disc wheels? I do use them for grinding tungsten rods for tig welding but I could use my belt+disc sander for those.

Perhaps I'll buy one cup and one flared wheel - and hopefully those two will cover everything I could possibly want to grind? I could buy another bench grinder too. That way I can have 4 different wheels for various things...the possibilities are endless but before all that I need to feel comfortable with the rest first. I'm finding the ball joint on it while gives compound angles it's hard to set it dead level in x, y and z planes but I'm sure it's all about practice and technique.

Anyone have links to their fav wheels on Amazon or ebay?


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## hman

OK, guys ... maybe off topic ... butI have a severe case of carborundum conundrum.  As far back as I can remember, it was always "NEVER use the side of a grinding wheel."  Then a while ago I bought Harold Hall's "Tool and Cutter Sharpening" (Workshop Practice #38).  And right there, within the first few pages, he was saying to use the side of the wheel.  What gives?????  Was the "conventional wisdom" I'd been taught simply a bunch of hooey ... or was Hall making a grave error?

An enquiring mind wants to know!


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## pontiac428

stioc said:


> Anyone have links to their fav wheels on Amazon or ebay?



You have entered the "real world" of grinding, and are now playing with the big kids.  Sorry, there will be no more deals to be found on Amazon or stale, crumbling, old stock from Ebay.  You gotta buy Norton, AKA "the real thing" from a supplier now.
https://www.mcmaster.com/grinding-wheels


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## pontiac428

hman said:


> OK, guys ... maybe off topic ... butI have a severe case of carborundum conundrum.  As far back as I can remember, it was always "NEVER use the side of a grinding wheel."  Then a while ago I bought Harold Hall's "Tool and Cutter Sharpening" (Workshop Practice #38).  And right there, within the first few pages, he was saying to use the side of the wheel.  What gives?????  Was the "conventional wisdom" I'd been taught simply a bunch of hooey ... or was Hall making a grave error?
> 
> An enquiring mind wants to know!



One should only grind on dressed surfaces that do not undermine the structural integrity of the rapidly rotating rock.  A little touch here and there is okay, hence Harold Hall's use of it, but it's not a quality surface and it will eventually ruin your stone.


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## hman

Makes sense.  Thanks!


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## stioc

pontiac428 said:


> You have entered the "real world" of grinding, and are now playing with the big kids.  Sorry, there will be no more deals to be found on Amazon or stale, crumbling, old stock from Ebay.  You gotta buy Norton, AKA "the real thing" from a supplier now.
> https://www.mcmaster.com/grinding-wheels



LOL I don't know about that, I'm having a love/hate relationship with the grinding rest right now. I think I need to get the techniques down and see what tools I can realistically sharpen with it before I go spend the $150+ on a nice grinding wheel.

Here I decided to turn an old screwdriver into a scribe. I set the fence to a 45 deg angle and then tilted the table down to a 'looks good' angle. This worked to create a tiny point...I guess I was expecting a long taper but it's a small diameter so a 45deg on it should be a short taper ending into a point, right?

This was during:




This was when I stopped:




I will post more of my trials and tribulations.


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## stioc

So in using the rest I realized that the slightly over sized knobs were getting in the way. So turned them down. I bolted them into another round chunk of aluminum slug with a threaded hole (already had this from another job) and chucked the slug up in the 3 jaw. 




Made for a quick 5 min fix.


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## stioc

Also made a small accessory for sharpening slitting saws. For the tooth stop on the side I couldn't find any spring steel strip so I cut off a piece of a cheap pocket ruler. However, I think I'll need to make it an infinitely adjustable tooth stop as per Harold's design. This guy is a smart cookie, everything he mentions in his design has a purpose behind it. Every time I tried to 'simply/lazify' his design I found myself redoing it his way.


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## pontiac428

stioc said:


> I think I need to get the techniques down and see what tools I can realistically sharpen with it before I go spend the $150+ on a nice grinding wheel.



A good, USA 60-grit white wheel should only set you back $40 or so.


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## stioc

pontiac428 said:


> A good, USA 60-grit white wheel should only set you back $40 or so.



Oh my bad! I think I was looking at the 7" ceramic/carbide grinding wheels in the cup style. But may be this 60 grit is all I need?


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## pontiac428

The white 38A compound in 60 grit leaves a very fine finish on HSS.  I find any finer grit than that is too slow, but that's my opinion.  Judging by what that hardware store grinding wheel did to your screwdriver, I'd say you are in for a treat once you get a proper wheel.


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## stioc

Cool! I just ordered the wheel. I guess I'll have to make an arbor adapter which is easy but modify the guard too...more projects!


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## stioc

This evening I decided to make an endmill holder. The reason being that the 5c blocks are way too big for this small rest. The endmill holders I will need are probably just the 1/4", 3/8" and 1/2". I mostly just use 1/4" and 3/8" endmills but some have 1/2" shanks. Besides, anything less than 1/4" will be hard to regrind. So I made the 3/8" one which came out good, but something went wrong with the 1/2" one where the hole went off center, wasted 40 mins making it 

Anyway, I decided to put the 3/8" holder to test real quick before calling it a night. I dug this old endmill up from my garage sale pile, Dykem'd it. The ends had some damage, wish I took a before pic but I was tired. All I can say is that this holder worked so much better than the 5c block. This is only my second time trying to sharpen the endmill's end. I think I hit the primary angle and the concave angle pretty close to what they should be. The only thing I see now I did wrong was I over did it by grinding it a bit too much so the land is a bit wider. This can be corrected by grinding the secondary relief angle which I haven't done yet. I'm pretty stoked


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## pontiac428

Nice job on the end mill and holders.  Remember, as you grind an end mill you cut deeper into the helix and the angle of the dangle changes- just like a drill bit ground off-axis with the flutes.  If you are doing a heavy grind, remember to re-set the mill in the holder before doing your final finish.  Also, I cut my back cut and relief angles first, then the gash cuts, then do the cutting edge last.  That helps me get the right amount of removal for the cutting edges and preserves the delicate edge from the rest of the process in case I nick one while grinding a gash cut, etc.  Also, interestingly enough, I find it more of a challenge to grind a perfect 2-flute EM than a 4-flute.  I guess 4 flutes are easier to "see", and the 2-flute has more "field" are on it's face to be relieved.  And the right grinding wheel will make those edges look more like mirrors than curtains.  All in all, you've really expanded your tool sharpening capabilities with this project!  I love grinding, and judging by the variety of tools you've tried out so far, you will too.


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## stioc

pontiac428 said:


> All in all, you've really expanded your tool sharpening capabilities with this project! I love grinding, and judging by the variety of tools you've tried out so far, you will too.



@pontiac428 thanks so much for your continued support and suggestions. Coming from you, someone who has a real tool grinder, it means a lot to hear that I've expanded my tool sharpening capabilities because I'm still unsure of how well this will work. BTW you're spot on in your assessment that despite a few frustrating moments I'm finding this tool regrinding thing a whole lot of fun 

Would love to see you and others post pics of what you're grinding even if on a different type of equipment.


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## pontiac428

I've got dozens of boring pics of lathe bits an such.  Most are hard to see the geometry and edges in once captured in 2D, but if you don't mind the clutter I can post.    Grinding is a lot of fun, and saves me a lot of money each year.  I'm always imagining ways I can grind - and often ways I can't accomplish a grind - with my equipment.  Right now I have a fixture block that's almost done to allow me to hold fluted countersinks at a 90 degree angle to the wheel to cut and sharpen countersink flutes.  We'll see how that works out.


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## stioc

The countersink fixture sounds pretty ingenious, would love to see it. Oh and I don't mind the 'clutter' at all. There's very little online about grinding everyday tools and cutters in a hobby shop so post away...please!


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## pontiac428

Here's some.
First, a single flute drill bit for spotting and precise-diameter drilling.




Some re-ground cemented carbide lathe bits, because they suck out of the box:




A RH finishing bit:







Grinder.  Made a few mods since, this is stock with Kipp levers and China wheel.  To the right you can see the lathe bit attachment and the spin fixture for flutes.




Heavy duty RH facing tool.  Did a LH of the same grind on the other end of the blank.




Top is a 60 degree threading tool, bottom is a general purpose tool.


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## stioc

Really enjoyed looking through those pics! What's the smallest endmill you've been able to regrind without a lot of issues?


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## pontiac428

With a white cup wheel, I can do 1/4" 2-flute end mills easily.  I could probably do 1/8" 2-flutes but haven't tried

With a CBN cup wheel, the smallest I've done is sharpen face only on 1/4" 4-flute mills.  If I wanted to do more than the face, I would need a nice flaring wheel in order to reach the relief cuts and back cuts.  That is all moot if I can't grind fine gashes.  I need another wheel for that.  Flaring wheel helps with those clearance and back cuts and will gash 3/8" 4-flutes (white wheel).

I don't know what the smallest flutes I can sharpen are.  Probably pretty small, like 3/16".  It's easy but dependent on having a fluting fixture.  It also changes the diameter of your mills and drills, so I only do it when the flutes are dull.  Keep spare band-aids on hand for this.


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## HBilly1022

For sharpening the ends of end mills I made one of these HH jigs. http://homews.co.uk/page124.html. This was the first of his jigs that I made and still use it for all my end mill sharpening (ends only). I have since made the simple rest, the advanced rest, the end mill flute sharpening jig, the lining tool and many other jigs. But I still use the end mill sharpener in the above link. I have one wheel on one of my old grinders that is dedicated to this use. It is so simple to use and does a GREAT job. I have found that there are 2 important issues to pay attention to for a successful grind; 1) the width of the primary land should be very small and 2) the side relief angle is very important. If either of these is not adequate the end mill will rub instead of cutting and will cause all kinds of grief. 

BTW, for the spring steel on the slitting saw fixture, I used some of the metal banding that is used for wrapping heavy packages. It works very well and it's my favorite price, free.


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## stioc

@pontiac428, that's pretty neat you can sharpen endmills that small with the tool grinder. I think 3/16" will be tough to do on this one.

@HBilly1022 glad to see there are a few others with Harold's rests out there. I wish I had made the advanced rest, it seems easier to use. Oh I've seen that endmill jig on Harold's site before but it's redundant for me with having made the simple rest first. The rest requires a bit more setup time but I'm getting more comfortable with it. Still making more accessories.

Last night I made another go at the 1/2" endmill holder., The hole is concentric up to 3/8" but going to 1/2" makes it out of center in two planes by about .030". Not sure what the deal is. I'll just skim the .030" off the square bar so it's concentric to the hole's center on all four sides.

I ran with it anyway using this 1/2" shank endmill as the test subject, it was pretty buggered up:






During (creating the gash and back clearance):










Done:





Cut two steps as a test:





Also did the chisel again.
Before:





After:





Edit: nevermind my previous comment about the rest's position. He was sharpening on the right side of the endmill, I sharpen on the left. duh stioc!


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## stioc

@pontiac428 I got the Norton cup wheel and as I'm thinking about the adapter for it I have a couple of questions about the width and also the plastic bushings.

1. So when I took off the existing cheap wheel, it has a plastic bushing in its arbor hole. Is that needed for the cup style wheel if I'm making the flange/adapter out of aluminum?

2. Below is what I'm thinking of making. What should the width of the flange/step be that the new wheel will sit on. See the red lines in the pic. Should I make it slightly thinner than the actual width of the wheel's hole? That way when I tighten the original clamp it clamps the the wheel and not the adapter. So may be .05" thinner?


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## Technical Ted

Look inside the HH book you have... he has drawings for what he recommends. I made these and they work well. In fact, I'm now using them on my KO Lee tool and cutter grinder.

No, you don't need the plastic insert. It's just a spacer for a 5/8" grinding wheel to adapt it to a 1/2" arbor. Just make your wheel adapters to fit your grinder's arbor. 

Ted


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## stioc

@Technical Ted thanks for the info. I didn't know KO Lee tools and cutter grinder uses a 1/2" arbor.

I did see Harold's design, he uses a two piece system (a bit more work -I'm lazy) but I'm hoping a simpler one as pictured above will do an adequate job since they were/are sold for the same purposes.


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## Technical Ted

stioc said:


> @Technical TedI didn't know KO Lee tools and cutter grinder uses a 1/2" arbor.



Depends on the model. Some use a tapered spindle like a lot of surface grinders do. Mine has 5/8" straight arbors.

The good thing about Harold's design is using two halves held together by bolts helps keep the wheel in the place on the arbors. Since you can't have a really tight fit, since the holes in grinding wheels are not held to tight tolerances, when you remove/re-mount a wheel it will not be in the same place  on a simple sleeve as it was when first mounted and dressed. It will require more dressing to get it to run true every time it is mounted. His design will minimize required dressing in the same way the wheel adapters do in surface grinders. Make the ID of the sleeve fit the grinder's arbor with a nice,, tight slip fit. This would only be an issue if you change wheels for different grinding operations. If you leave one wheel on all the time it's a moot point.

Oh, forgot to mention, for the nicest grinds, you'll want to dress your wheels accurately so they run very true. You can use your grinding fixture, one of the holders you made for it and a diamond dresser to do this. This isn't absolutely necessary, but will really make some nice grinds. You can dress by hand with a dressing stick, like a Norbide stick, etc., but the diamond does a better job. I even make a little holder for a diamond for my pedestal grinder where I hand sharpen bits. 

Ted


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## pontiac428

Make one arbor per wheel of the locking type. When you dress that wheel, it sets it's center based on the relationship between spindle, wheel, and arbor. Thus, the arbor and wheel are married. They change as a pair, one arbor per wheel.


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## stioc

Technical Ted said:


> Make the ID of the sleeve fit the grinder's arbor with a nice,, tight slip fit. This would only be an issue if you change wheels for different grinding operations. If you leave one wheel on all the time it's a moot point.



This! I won't be changing wheels, if/when I feel the need I'll put a different wheel on the other side of the grinder. So back to the simple adapter/sleeve - I measured the width of the grinding wheel's hole and it's .47" - probably .5" nominal size so I'm going to make the step of the adapter .40" that way the clamping washer puts the force on the wheel and not on the aluminum flange.

Thanks for the other tips and truing up the wheel etc guys, makes perfect sense.


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## stioc

I got the adapter done tonight and excited I mounted the new wheel...holy vibration batman! Not that the grinder didn't vibrate before but this is worse.

I put an indicator on the two surfaces that the grinding wheel sits on, the back and the center of the adapter- both are just about .0005". The fit is a nice slip fit on both the arbor and the wheel, I was actually proud of myself there.

So, I don't know what the deal is...I haven't trued it up, so may be that will help?


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## Technical Ted

What wheel, brand/size/style/number are you using? If you spin the wheel mounted on the grinder by hand does it look like it's running out?

You said that the adapter you made fits both the grinder's arbor and the wheel without play so that sounds OK. Some people balance their grinding wheels so that is a possible option. If it were me, I would dress the wheel with a diamond dresser using one of your holders on the grinding fixture you made so it is nice and true and see what that does. 

Ted


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## stioc

It's a Norton 38A Type 6 Straight Cup wheel. I put the old wheel back on (which doesn't pass the 'ring test' btw) and it's way better. So there's definitely something going on with the adapter or the wheel.


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## pontiac428

Dressing the wheel will bring it into balance.  If that doesn't work, you can balance the wheel on a static point and remove a little bit of material to adjust as if static balancing a tire.  I've never done that, just read a writeup on how it's done.  Usually wheels balance out with dressing.


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## stioc

pontiac428 said:


> Dressing the wheel will bring it into balance.  If that doesn't work, you can balance the wheel on a static point and remove a little bit of material to adjust as if static balancing a tire.  I've never done that, just read a writeup on how it's done.  Usually wheels balance out with dressing.



Even a quality wheel like the Norton will require dressing out of the box? I ask because I've never replaced a grinding wheel before.

I hope you guys are right though because I keep thinking I failed at making the adapter somewhere but can't see where. The two surfaces the wheel registers on check out as well as the fit on the arbor.


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## HBilly1022

I had similar issues with my grinder. At first I thought it was the cheapo grinder but after checking it over and running it without the wheel I determined it was not the grinder. Then I dressed the wheel using the HH rest and a diamond point dresser. No change. I ended up making something like Johnny C did in this thread  https://www.hobby-machinist.com/threads/do-they-make-bench-grinders-that-dont-vibrate-so-much.67471/#post-564126 and the difference was astounding. Ended up with a very smooth running grinder that amazes me every time I turn it on. You will also see there is a OneWay balancing system that does the same thing but may not be applicable given the wheel and adapter you made.


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## pontiac428

Everything needs to be dressed true when new.  The arbor and your spindle are part of that equation, and dressing levels the differences.  It's not common, but I've had a wheel or two new wheels (one 6" bench grinder wheel in particular currently on my pedestal grinder comes to mind)  that needed 1/8" of dressing before smoothing out.


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## Technical Ted

stioc said:


> The two surfaces the wheel registers on check out as well as the fit on the arbor.



How does the arbor fit the wheel? Even if you made it right on 1.250" the wheel might fit sloppy and maybe you can wrap a shim around the arbor to help align the wheel. But, you should still dress it with a diamond. 

Also, another thing to put on your to do list... you'll want to extend the wheel guard so you are protected in case the wheel explodes. Safety first!

Ted


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## stioc

Will do more checking and testing tonight.

The thread that HBilly linked to, I found @MikeWi post #20 similar to my situation, looks like the solution was to dress the wheel!

@Ted, I was looking at the wheel guard but I haven't yet figured out how to extend it but I will (that was going to be my next project on this after mounting the new wheel.


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## ericc

All this hassle with the balance has made me want to go with a slow speed grinder.  I just saw my friend's this weekend, and it is great.  That will be my next one.


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## stioc

Haha, or just buy the real tool...but where's the fun in that if you're a glutton for punishment like I am lol

Well, things are much better now after dressing the wheel. There were a few high spots. When it's running at full speed it's about the same as it was with the original wheel, in fact, it sounds/feels smoother. However, at spin down, may be around 1500-2000 rpm there's some wobble/shake but not terrible. My grinder isn't bolted down and it doesn't walk around on the MDF board it's sitting on so I think it'll do.




As for the guard, my original one covers 1" of the 1.5" already... I can't cover the sides on this one either since this is a cup wheel and I'll be grinding on the side so I'm thinking of leaving it as is or may be fab some sort of a half guard?


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## pontiac428

Glad you tamed that wheel.  I think your guard has adequate coverage.  If you put any more guarding in place, you wouldn't have room left to grind.

Have you had the chance to grind some HSS with that wheel yet?  You're in for a treat!


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## stioc

I haven't had a chance to use it yet, was too busy trying to get it to run smooth but I plan to as soon as I find some time. I have another small upgrade in mind so I might start on that first before using it...rabbit holes I tell ya!


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## Technical Ted

stioc said:


> As for the guard, my original one covers 1" of the 1.5" already... I can't cover the sides on this one either since this is a cup wheel and I'll be grinding on the side so I'm thinking of leaving it as is or may be fab some sort of a half guard?



Well, it's your face and eyes so you be the judge. Look at the wheel and current guard and get your face down close like it would be while performing a touchy grind. What do you think would happen if the wheel exploded? Feel safe? If so, don't worry about it.

Ted


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## stioc

Way to make a point and point taken!  To be honest I don't like anything spinning at high RPM near my body and sure as heck don't want a piece of rock hitting me in my face if it explodes. However, the conundrum is how do you cover the wheel without impeding access? Even in Harold's design he covers just the top of the wheel, it's open on the sides.


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## Latinrascalrg1

stioc said:


> However, the conundrum is how do you cover the wheel without impeding access? Even in Harold's design he covers just the top of the wheel, it's open on the sides.



Maybe this is where a face shield or at the very least a pair of safety glasses would prove to be beneficial invest to keep handy in the shop!


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## Technical Ted

You might get some ideas on how to make one by looking at some pictures of tool and cutter grinders. I know you already have the original to work off, but you might be able to design an extension what serves the purpose. When I got my KO Lee T&C grinder it came with no guards so I made this one. A partial guard that I can position depending on where/how/what I will be grinding and where my face will be.




Maybe you can remove the original one and make your own? Or maybe you can incorporate an extension off the existing one that you can position where and how you need it? Look at some pictures and I bet you'll come up with a good idea or two.

Ted


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## stioc

So I messed around with the grinding rest last night since I need the practice to get comfortable, I'm finding setting all the various angles a bit of a pain but hopefully as I develop my own system it'll get better with time. For example, setting the distance quickly from the grinder to the table without disturbing the angles I already set aka...order of operation is important.

Anyway, I found an old flat head screwdriver with a chipped end, so I grinded the end flat and then the side tapers...came out fairly even. As for the surface finish I'd say it hasn't improved a whole lot with the new wheel but there's improvement. I think if I use the front section of the wheel I get more irregularities and that's probably because of the vibration/buzzing of the grinder itself. Generally speaking if I skirt the corner of the wheel's edge the finish is better. Again, I just need more seat time to know what works what doesn't.


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## stioc

BTW, for those reading this now or in the future and are interested in making something like this, I happened to come across this kit made by someone in Australia (check their website for pricing). It looks pretty neat. Not sure if this will sharpen slitting saws and other tools but probably can be adapted with a couple of accessories?


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## pontiac428

I thought I'd report back with what I tried to pull off a quarter grind with. I didn't think it all the way through. Not low enough on the wheel. It will be easy to make a low mount that replaces the upper blue arm, so I'll try that.


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## stioc

pontiac428 said:


> I thought I'd report back with what I tried to pull off a quarter grind with. I didn't think it all the way through. Not low enough on the wheel. It will be easy to make a low mount that replaces the upper blue arm, so I'll try that.



Can you flip the dovetail holder around so the knob is where the tool/part is, then rotate the blue arm 90 degs so the part/tool you're making is the only thing that touches the wheel?


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## pontiac428

If you don't mind me continuing to post in your thread, I managed to find a way to cut a quartered single flute (I think).  I'll heat treat this W2 blank countersink and give it a shot grinding with the setup as shown.  If this works, I can grind all of the other surfaces of the tool to finished size... and make 20 more to cover the included angles that I am missing.


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## stioc

Nice! I don't mind at all...post as much grinding related stuff here as you (or anyone else) would like.
May be we should have a thread called "GOTD - Grinding of the Day thread"


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## pontiac428

Success! While not what I would consider a precision piece, it will work. I'm going to have to churn out a few more if these.

If I'm to pursue tool making, even at a putterer's pace, it's going to take a bigger, more capable grinder. Probably one that runs coolant. Hmm, maybe not right away.


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## stioc

Woah! that's a great looking countersink, looks like the real deal. So I have a question, how did you cut that curved drill-bit like flute?


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## pontiac428

The curve comes from the intersection of two cylinders.  The grinding wheel is a cylinder, and the tool is a cylinder (in its primitive form).  It's only one cut, the plunge of the dressed face of the wheel  to make the cutting edge.  The back side of the cut is whatever is left over from the procedure, which is a curve in this case.  It looks neat.  I could cut a second flute on the opposite side, but I think it would defeat the purpose (low chatter and good centering tendency) of a single quarter-cut flute.  Anyway, now that I've got the bugs worked out, I would like to try to make some more angles in this 1/2" size and order up some 3/4" steel to make some larger ones.


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## stioc

Ahhh! I see it now, it does look neat.   What steel are you making these out of?

As an aside I personally like zero flute countersinks because, for me anyway, they don't create any chatter at all.


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## mattthemuppet2

how did you get the relief behind the cutting edge of your countersink? I thought that single flute countersinks were ground using a cam based set up to provide back relief for the cutting edge that went the whole way round the tool


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## pontiac428

mattthemuppet2 said:


> how did you get the relief behind the cutting edge of your countersink? I thought that single flute countersinks were ground using a cam based set up to provide back relief for the cutting edge that went the whole way round the tool



I used W1 water-hardening tool steel.

I used a single-facet design.  The cutting edge is ground by first indexing the cutting flute to the horizon, then setting 15 degrees of lead into the spindexing head.  The work is moved toward the wheel just enough to make a small flat.  Then the work is rotated another 15 degrees, the work is infed into the wheel about .015" (the back relief), and rotated through the remaining 240 degrees of the cone.

I made a craptacular drawing below using paint, because that's all I have on this computer.


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## bikr7549

Hello, new member here. I have purchased Harold's book and plan to start making the simple grinding rest but have the same ball material question asked early on, what type of plastic is used for the ball? McMaster has nylon and delrin in the 1" size, not expensive but I want to get the right one. Any suggestions? Do not have a ball turning fixture, yet.

Thanks,
Bob

PS, Harold is not accepting correspondence. Not sure how recent that is but I just looked at his website (was planning to ask him my question) and saw that he has stopped writing.


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## Technical Ted

For this application, I don't see where it would make much difference between the two... Delrin might machine a little nicer.

I made mine out of steel with my home made radius cutter (ball turner) and it works fine.

As I have posted on this site previously, I made both the advanced and simple fixtures and between the two, the advanced is much better hands down. Much easier/quicker to setup at the required compound grinding angles. 

Ted


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## stioc

This is the one I used: https://www.mcmaster.com/6046K13

Happy New Year everyone!


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## bikr7549

Thank you, phenolic being a harder material is what I thought might be needed, or preferred at least to a softer plastic.


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## Johan Crous

I see that your fence carrier is way longer than my plan. It also features several holes, where my plan shows only one threaded hole. Is there a reason for that?


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