Budget HSS lathe tool grinder

[Jonathan Coates]

I noticed that the sanding machine that I bought to assist a lady friend with a project could be repurposed to get various angles roughed out on a HSS tool bit. It actually works a bit better than it ought to, getting the angles to where they need to be. Of course the angle scales on the machine have to be ignored, but there are ways to measure angles more accurately.

 

[Richard Carlstedt]

My belt sander is my 3rd hand , they are awesome machines
You need to easily modify them a bit for extracurricular applications
Make the table easily adjustable-mark the table- use collet blocks
try to eliminate using wrenches , you want fast adjustment
here are a few pics and a simple fix when I had to drill a hole in tight quarters using a right angle unit. just ground a hex on a old drill as seen
It also helps to balance all rotating parts like pulleys ect , and mount the base and motor on heavy wood ( 2" thick) base to minimise vibration and get a smooth machine.
Rich

 

[WisJim]

There is a 3 part article online about using a belt sander to sharpen lathe cutters, and a related article about modifying a belt sanding, including making a better table and other modifications.
https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander/
https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander-part-2/
https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander-part-3/
https://www.machinistblog.com/modifying-a-craftsman-2-x-42-inch-belt-sander-for-tool-grinding/

I've been looking for a decent quality affordable sander to give this method a try.

 

[Jonathan Coates]

I've been looking for a decent quality affordable sander to give this method a try.

The one I have was around £150 GBP, I don't think I could buy a motor and the materials to make my own for close to this price.

 

[timo_gross]

I've been looking for a decent quality affordable sander to give this method a try.

You can make your own belt sander. I was inspired by this video, made the size to fit the belts that I can easily buy.
I think I spent at the end almost as much as for buying one.

Greetings Timo

p.s. you do not need any castings. Welding the structure worked. Screwing it together would have also worked.

 

[L98fiero]

I think I spent at the end almost as much as for buying one.

Where's the fun in that, why buy something when you can make it for 5 times the price?

 

[Shopgeezer]

I rough out my lathe tools on the grinder because it is faster but finish them on the belt sander. I bought a belt from Lee Valley Tools that is designed specifically for sharpening. It does a great job, especially on the diamond tools that I have come to like a lot.

 

[awake]

I made a 2x72 belt grinder out of materials at hand; the only thing I recall buying was a cheap PWM generator to drive the treadmill motor circuit board - only a few dollars. Details and plans here: https://www.homemodelenginemachinist.com/threads/lets-talk-belt-grinders.33242/

Despite the compromise of using a treadmill motor, and the inevitable things that I would do differently if I made another one ... this has been one of the best tools I have ever made, and I use it all the time. I *still* need to made a tilting table - 99% of the time I want it square, but once in a while a tilt would be handy. And I am *still* running the "temporary" 3d printed idler wheels, which continue to work quite happily with no apparent problems, despite extensive and sometimes quite heavy usage.

Highly recommended - for me, at least, once I had this tool, I wondered how I ever got along without it. It can grind off metal in a hurry, but also fine-tune right up to a scribe mark. It has definitely changed the way I approach some tasks; depending on the exact precision needed, I find that it is often easier to grind up to a scribe mark than it is to set up a complicated jig on the mill.

 

[timo_gross]

I made a 2x72 belt grinder out of materials at hand; the only thing I recall buying was a cheap PWM generator to drive the treadmill motor circuit board - only a few dollars. Details and plans here: https://www.homemodelenginemachinist.com/threads/lets-talk-belt-grinders.33242/

Despite the compromise of using a treadmill motor, and the inevitable things that I would do differently if I made another one ... this has been one of the best tools I have ever made, and I use it all the time. I *still* need to made a tilting table - 99% of the time I want it square, but once in a while a tilt would be handy. And I am *still* running the "temporary" 3d printed idler wheels, which continue to work quite happily with no apparent problems, despite extensive and sometimes quite heavy usage.

Highly recommended - for me, at least, once I had this tool, I wondered how I ever got along without it. It can grind off metal in a hurry, but also fine-tune right up to a scribe mark. It has definitely changed the way I approach some tasks; depending on the exact precision needed, I find that it is often easier to grind up to a scribe mark than it is to set up a complicated jig on the mill.

Haha, I never understand the use of treadmill motors. For me industrial motors (at cost) are more easy to find.

I get the impression that ( most?) treadmills are produced and shipped around the globe just to provide motors.

Doctor to patient: "You are overweight, you should stop eating unhealthy food, stop smoking, stop drinking and.... Do some exercise!" ....

"Honey what did the doctor say?"....
"Oh he said, I should order a big 3-phase motor and donate it to the local maker space! He thinks it will make me feel better about myself!"

Greetings Timo

joking aside, the belt sander is one of my most frequent used machines.

 

[awake]

Exactly - I love seeing a treadmill discarded on the side of the road. Sometimes (rarely) the motor is bad; sometimes (rarely) the controller is bad, or is of a proprietary design that is difficult to hack. But most of the time, both work fine, or the motor from one can be married to the controller from another. Most of the time, the controllers are one of the recognizable MC- series, and there is enough documentation available to know how to connect to them to drive them. Definitely not as beefy as a 3hp 3-phase motor on a VFD ... but given the price (free), they work great for me!

 

[Steamchick]

Unfortunately, in the UK, we don't have the attitude to dump stuff on the road-side "to be collected" - by anyone. But I do find it works for scrap wood (for fuel) and steel (scrap). There are "collectors" who collect things we do not lock-away out of sight! But most people (responsibly?) take all their "used goods" to the waste recycling depot... where they will not even sell you a motor and controller!
K2

 

[awake]

No dumpster-diving? That is just downright depressing ... the majority of the stock I have on hand, and consequently the materials used in building belt grinder, slip roll, and any number of other tooling has come from the metal scrap bin. I should note that I do have permission to "dive" there.

 

[Brian Rupnow]

I have a 6" wide belt grinder that I built for smoothing the edges on flame cut plates when I was building hot-rods. I have a two horsepower 1750 rpm electric motor on it, that was originally the power for a walk in freezer. When I turn that belt sander on, all the lights in Barrie go dim until the belt is up to speed.

 

[Old School]

Steamchick I don’t know where you live in the UK but it’s pretty common where I live Leicestershire. I’ve not anythingof use yet but live in hope.

 

[Steamchick]

When I asked the guys about obtaining a bit of something scrap they said that had been banned... someone working there had got into some bother for allowing it, so no-one is allowed to take stuff away.
Ho-Hum.
K2

 

[awake]

With respect to scrap yards in this area (North Carolina), it varies widely. Some do not allow any scrap-picking; others do. My primary source is not actually a scrap yard, but a metal scrap bin used by the institution where I work. I obtained permission to scavenge from it some 20+ years ago, and periodically "renew" that permission / check to be sure it is still granted. Since this is an educational institution, the kinds of scrap that go through the bin can vary wildly from one week to the next. But decommissioned / broken exercise equipment does come through from time to time, and there is often some very useful material there including but not limited to treadmill motors. I especially love weight machines, where the weights are 1" thick plates. Also useful are some of the decommissioned lab equipment, which can yield both stainless steel sheet material and sometimes aluminum plate. Sigh ... just thinking about it gives my heart a flutter!

 

[Jonathan Coates]

Little bit more of an upgrade. These diamond impregnated discs are quite cheap on Ebay so I ordered myself a six inch one and grafted it onto the "tool and cutter grinder". It might need some fine tuning but it spins OK and the adapter bits are very simple to make.

 

[Steamchick]

I have a cup "stone" with diamond grit for touching-up the replaceable carbide tool bits when the edge goes off. But I am unsure of the correct speed for these things. A recent post suggested very slow, just a few hundred rpm, not 10,000rpm-ish like carborundum? I am not running in a water bath as the 240V motor may get very excited with splashing water! I also have tried some diamond discs in my angle grinder, but not found the right application ... yet! (one disc turned red hot in seconds trying to cut 2mm. steel sheet! - Obviously the wrong application!).
Any clues as to grinding speed for various steels, carbide, etc.?
(Diamond Hand-tools work well, limited by the speed of my hands).
K2

 

[Jonathan Coates]

There's no indication on the disc or website about the running speed of these discs. The sanding thing runs very much slower than an angle grinder and I've seen these used on such on YouTube. Stefan Gotteswinter has a very low speed diamond wheel thing which runs very slowly. I'll give this thing a try and see what happens. What could possibly go wrong?

 

[Steamchick]

• All the diamond dust comes off the disc.... Nasty if you breath it or get the "smoke" in your eyes!
• The disc can get too hot and distort, causing the part to grab and pull out of control?
• If you exceed the max rpm stated on the label you risk the disc stretching and possibly distorting or breaking...

FIT the rest, HOLD part well, not just finger tips for small parts, but Mole grips or something so you keep flesh away from grinding surface...
NORMAL safety for grinding.
WEAR EYE PROTECTION.
While slower is safer, too slow will wear the grinding wheel not the part you want to grind... Carborundum discs are sacrificial when grinding, but diamond wheels are not.... so the whole thing is actually a different science, that seems to be unpublished - yet? - The diamond "dust" is just a surface coating within the surface of the aluminium disc. Very Slow speed & High pressure can simply rub-it-off! - I think? - Or maybe too fast? - I just don't know having had mixed good and bad success.
(Well, you asked...).
K2