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

 

[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)

 

[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...

 

[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

 

[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

 

[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

 

[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.

 

[brino]

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


Thanks for sharing this!
-brino

 

[Janderso]

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

 

[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