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Grinder for lathe cutters

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ttabbal

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#1
So, I want to make bits. I have a harbor freight bench grinder. Not a great tool to be sure, but can it be made usable?

I've seen the threads talking about modifications to a belt sander. That's another option. Any suggestions on what to look for?
 

darkzero

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#2
Sure you can if that's all you have for now. But it would be best to get some quality grinding stones for it. The majority of bench grinders come stock with crappy stones. That's usually what makes them vibrate like crazy.

I wish HF still sold their tool grinder, they used to only be $130 & with a 20% off coupon you could get it for $104 + tax. Every time I think about it I regret not getting one at the time!
 

ttabbal

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#3
Thanks for the reply. The HF tool grinder looks like it was a pretty good deal.

My bench grinder does vibrate pretty good, and the stone that HF included is probably just good enough to usually not explode when you turn it on. :) Can someone recommend a decent brand that doesn't break the bank?

I imagine I would have to freehand it or add a decent rest for the workpiece. The bit of angle iron that appears to just barely qualify as metal isn't very good at staying put.
 

mikey

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#4
Tell you what I would do. If I was going to use the grinder only for lathe tools, I would consider CBN wheels. Of course, they're expensive. If I was going to use abrasive wheels then I would contact Norton and ask them what wheels they would recommend. I mean, they make em', right? They should know. Wheels are more fragile than most of us think and when we go putting out body weight behind a tool to get it to cut then we are subjecting that wheel to more force than it was intended to take. Better to get the right wheel material in the right grit for the purpose - Norton will know.

On the other hand, a belt sander cuts cooler, faster and flatter. Belts are cheap, do not require dressing and do not blow up (but they can snap if they're old). It takes seconds to change belt grits and you're back to grinding and you can take a tool from shaping to a near mirror finish in under 15 minutes without significantly changing it's shape.

I have ground tools for well over 25 years, on bench grinders and belt sanders. While I am definitely in the minority among hobby guys, I much prefer a belt sander for tool grinding.
 

ttabbal

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#5
I have ground tools for well over 25 years, on bench grinders and belt sanders. While I am definitely in the minority among hobby guys, I much prefer a belt sander for tool grinding.
I like the look of using a belt sander for this. Do you have suggestions for things to look for in a good tool for the job?
 

mikey

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#6
I like the look of using a belt sander for this. Do you have suggestions for things to look for in a good tool for the job?
There we have a problem. I have an old Sears 2 X 42, 1/2HP belt sander that works well for me. It is still sold but uses a 1/3HP motor that bogs down sanding wood. If you ever see a 1/2HP version, grab it. Short of a 2 X 72 grinder, it is the best tool grinder I know of. It has a squarish motor housing and looks like this:

Sears-Craftsman-Model-351215420-Tabletop-2-x-42.jpg

A belt sander for tool grinding must have:
  • Full and unobstructed access to the right side of the platen. There cannot be ANYTHING in the way; this includes covers or structures or housing or anything. The reason is that the back rake angle on your tool is ground on the right side and edge of the platen so that area must be clear.
  • The platen must be removable/replacable and very solidly mounted to the chassis. In use, the platen cannot flex so platens that mount on only on end (like those seen on 1" belt sanders) will not work.
  • The platen should be very flat and long lasting. I use a piece of O-1 precision ground steel to which I epoxy a ceramic glass (Pyroceram) liner for use as a platen. This platen is attached to an angle iron piece that bolts to the chassis of the grinder. In use, there is zero flex and the glass liner stays flat under heavy grinding for many years.
  • You must have a tool rest that is solid and unyielding but is quickly adjustable to precise angles. It should be made of steel so the work piece does not drag or catch. A protractor slot is optional and sometimes useful.
Finding a belt sander that meets these criteria has proven to be difficult. I recently spotted a little Grizzly sander that might work. It uses 25" long belts so I suspect belt life and availability may be an issue but you can see it here:
http://www.grizzly.com/products/Combo-Belt-Sander-Grinder/H7760

It is a 1/2HP model and you can even mount a 6" wheel on it. I don't know how it will work but with the cover removed, the platen is exposed on the right side. The platen is removable and the work table locking bolt is up front so that a custom table could be built. I don't know what the belt housing is made of but if it is steel then its possible to cut and extend it to accommodate a longer belt. This is the only belt sander I have seen that meets my criteria and I'm waiting to either see a review or if Amazon will carry it so I can get it with free shipping. If I buy it, I'll definitely review it here.

Sorry I don't have better news. If you can afford to build a 2x72 belt sander then that would be ideal.
 

Rockytime

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#7
I have a HF 6" bench grinder that I use. I use a Norton aluminum oxide wheel along with one of the original wheels. I did make precision washers as well as wheel reducers to replace the loose fitting plastic ones. Vibration is fairly soft now. Most importantly is the tool rest. I use a Veritas tool rest which Is pretty good. I'm 79 sand if I were 10 years younger I would use CBN wheels on a Baldor grinder. If I were 10 years younger I would spring for a new DM 13" lathe. I have sharpened on my HF belt sander but belt changing is a pain and it rattles. Bearings are probably going out, it's very noisy. Mikey has some great advise! 2-20170911_165415.jpg 1-20170911_165432.jpg 3-20170911_165449.jpg 2-20170911_165415.jpg 1-20170911_165432.jpg 3-20170911_165449.jpg
 

ttabbal

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#8
Thanks for the pics and mentioning the tool rest. It looks like a reasonably priced and functional unit. I might have to pick one up.
 

Aaron_W

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#9
Mikey, I kept looking around for 2" belt sanders after your comments in my similar post a few weeks back. I found one by Palmgren that looks similar to the Grizzly you found, but uses 2x42 belts instead of 2x27. The small belts was one possible drawback you noted with the Grizzly.

Unfortunately seems to be online only so again not easy to find a physical example to look at. All the photos also appear to be the same stock photo from the left side so not terribly useful for determining how easily it could be made to work for tool sharpening. Unlike the Grizzly the Palmgrens appear to be available, I even saw them listed at Tractor Supply for online purchase.

https://www.amazon.com/Palmgren-Belt-bench-finishing-machine/dp/B0006577HI
 

mikey

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#10
Yeah, saw that one. It's basically the Sears belt sander under a different brand. It is a 1/3HP grinder and trust me, I can stop the motor dead just grinding wood. I own the 1/3HP Sears model and it will not grind tool steel without bogging down. My old belt sander is 1/2HP and it is vastly superior, although the chassis is the same.
 

Rockytime

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#11
Yeah, saw that one. It's basically the Sears belt sander under a different brand. It is a 1/3HP grinder and trust me, I can stop the motor dead just grinding wood. I own the 1/3HP Sears model and it will not grind tool steel without bogging down. My old belt sander is 1/2HP and it is vastly superior, although the chassis is the same.
Hi Mikey, I'm bidding on a Craftsman like yours. It is an older unit looking exactly like yours but it is a 1" belt. I now have three belt sanders, a HF, 1" sander from MSC purchased years ago and a 4" Craftsman mostly used for sharpening wood turning tools. Not sure If I'll win the bis or not but worth trying.
 

mikey

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#12
Hi Mikey, I'm bidding on a Craftsman like yours. It is an older unit looking exactly like yours but it is a 1" belt. I now have three belt sanders, a HF, 1" sander from MSC purchased years ago and a 4" Craftsman mostly used for sharpening wood turning tools. Not sure If I'll win the bis or not but worth trying.
Good luck, Les! The only difference between the 1" and 2" models are the wheels. If you win it and wish to use 2" wide belts, Sears still carries the wheels for their 1/3 HP model sander so you can just change them and use 2" wide belts. You can certainly grind tool bits on a 1" belt but the 2" belt gives you more stroke and they last longer since you aren't concentrating all the cutting in a small space.

My brother owns a 1/2HP, 1" sander like the one you're going to win. He doesn't know it yet but if my sander ever dies, his is coming to my house!
 

Aaron_W

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Yeah, saw that one. It's basically the Sears belt sander under a different brand. It is a 1/3HP grinder and trust me, I can stop the motor dead just grinding wood. I own the 1/3HP Sears model and it will not grind tool steel without bogging down. My old belt sander is 1/2HP and it is vastly superior, although the chassis is the same.

Good to know, I was considering it as a future purchase. I find it really odd how difficult it is to find an adequate belt sander for this purpose since it does seem to be a better way to grind tools. Even that Grizzly that might work seems to be hard to get.
Unless I get lucky and stumble onto an old Sears sander like yours on ebay or a garage sale, it may become a future DIY project.
 

mikey

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Unless I get lucky and stumble onto an old Sears sander like yours on ebay or a garage sale, it may become a future DIY project.
Look hard, Aaron, look really, really hard for one. They are good sanders, which is why they're so rare on the used market. Lots of newbie knifemakers own them. Your best bet is some guy who doesn't know what he has.
 

Aaron_W

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#16
hope i'm not hijacking this thread, but i've seen rikon mentioned once or twice on the forum.... anybody have experience or suggestions with using these for shaping metal cutting tools?

https://woodturnerswonders.com/coll...-hp-grinder-with-two-4-in-1-design-cbn-wheels

(https://woodturnerswonders.com/collections/rikon-grinders)
That is what I decided to do. I went with the Rikon 1hp grinder with the idea of upgrading to cbn wheels down the road.
I just got it and haven't had a chance to use it yet, I haven't even been home since it was delivered so can't offer any opinion of it.
 

ericc

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#17
Do these Rikon grinders have guards? I think they wouldn't be safe with conventional wheels.
 

Aaron_W

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#18
Stock they do come with covers, and tool rests. The ones Woodturners offers for use with wide CBN wheels do not.
 
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mikey

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hope i'm not hijacking this thread, but i've seen rikon mentioned once or twice on the forum.... anybody have experience or suggestions with using these for shaping metal cutting tools?

https://woodturnerswonders.com/coll...-hp-grinder-with-two-4-in-1-design-cbn-wheels

(https://woodturnerswonders.com/collections/rikon-grinders)
If I was to buy one, I would email Ken Rizza and discuss it with him regarding grits he recommends for shaping and finishing. I would also buy wheels without a radius on the corners for tool grinding; you need a sharper edge to grind the rake angles.
 

Z2V

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#21
That's a sweet deal there. What maybe 3hp? Probably 3 ph? You stole that for 6
 

Z2V

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#23
Even Sweeter!!!
Great find, I can never get that lucky
 

ch2co

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#24
Mmmm Baldor, me likes Baldor.
Great buy, congrats.
 

Z2V

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#25
I just made these rests for my 8" Craftsman. The rest itself is steel but the remainder is aluminum. I originally made the whole thing aluminum, it didn't take long to realize that mistake. Adjustable up, down, in, out and any needed table angle.
 

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Aaron_W

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#26
I got home last weekend and had a chance to set up the new Grinder. It is considerably larger that I expected. Although the wheels are the same diameter the overall machine is much beefier than the 3/4 hp Dewalt grinder I had looked at. Factoring the better quality grinding wheels it comes with and overall quality (more power, more solid construction), I think the Rikon grinder was worth the extra $100.
 

DHarris

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#27
eastwood belt sander.jpg For the low rent end of the spectrum - Eastwood makes a small machine - has a 2 x 28" belt on one side and an 8" grinding wheel in the other. Motor is 1/2 hp. Site says they stock belts too - don't know what the selection of grits might be though. Price is listed just going on sale as $89.97

edit to fix photo & update Sale price
 

mikey

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#28
The Eastman sander won't work for tool grinding if that's what you're looking for. The platen and tracking mechanism are integrated and you cannot put a Pyroceram liner on it. In addition, the platen extends beyond the belt so you cannot grind the rake angles on it. Sorry, Dave, but not a good candidate for tool grinding. What's worse is that I don't have a better option beyond the Grizzly combo we discussed.
 

Desolus

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#29
So, I want to make bits. I have a harbor freight bench grinder. Not a great tool to be sure, but can it be made usable?

I've seen the threads talking about modifications to a belt sander. That's another option. Any suggestions on what to look for?
I use a wrongfu harbor freight bench grinder to make my tools, I freehand everything, holding the tool steel with a visegrip. I'd advise you to get something that will turn a grindy bit for the cheapest price to hp ratio you can find IF, all you want to do with it is grind lathe tools; if you want to use it for anything else I'd still look for cheapest price to HP ratio, but with a few more qualifiers added depending on what else you want to do with it. With that said, I would buy the absolute best grinding wheels money can buy, if you can afford them or not. Abrasives will pay you out in spades if you get good CONSISTENT ones. It's a huge deal to get a consistent abrasive, so much so that the range of particle sizes in most grinding wheels is actually quite large, and for wrongfu wheels can be several orders of magnitude in either direction from the grit size, causing gouging or painfully inefficient cutting. Any manufacturer of precision tools will be proud enough of their product to list the abrasive particle size range somewhere in the tec sheet; and you can always just ask.

Something else to consider is the abrasive particle shape, in the better wheels the particles are sorted not only by size, but also by shape, and only the particles with better cutting geometry are used. In the best wheels, care is taken to align those particles in a specific direction for the most efficient cutting possible.
 

waynecuefix

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#30
So, I want to make bits. I have a harbor freight bench grinder. Not a great tool to be sure, but can it be made usable?

I've seen the threads talking about modifications to a belt sander. That's another option. Any suggestions on what to look for?
I use a Black and Decker BT3500 6" bench grinder with coarse and fine stones, which is about as cheap as they come. I have used it for grinding bits mostly 5/16 and smaller for several years and it does a decent job. I first ground bits holding them in my hand against the rests which I adjusted for the desired angles. Then I purchased a small cheap Chinese quick change tool holder for 10.00 on Ebay to put the bits into for grinding. Now I am seeing these for 5 bucks. Later I found a tool bit grinding holder for 25.00 on ebay which can hold the bits at different angles on the grinder rest for shaping the bits. There are diagrams on the internet which show how bits are ground. You may be already beyond all this and way ahead of me but I thought it might help someone. I am strictly amateur and this is my limit LOL. Wayne.

Here is a current quick change bit holder like mine available directly from China for 5 bucks. Holds up to 1/2" (13mm) bits. I use one for holding bits when sharpening. I didn't cut off the height adjust stud on mine but it could be removed to get it out of the way.
Q C TOOL BIT HOLDER CHEAP 5 DOLLARS.jpg

Here is the other holder I found on Ebay. The slot holds a 5/16" bit. I don't have a source for these, it is an old one. I wonder if any like these are even still made. As you can see there are various slope possibilities for making the rake angles and even the bit slot is sloped.

TOOL BIT SHARPENING FIXTURE 4 (2).jpg TOOL BIT SHARPENING FIXTURE 2 (2).jpg
 
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