Building A Tool Post Grinder

Cameras can really fool your eye! Your eye compensates for perspective better.
 
Wow you are doing great work. I'm going to make some variants of these Themac extension spindles. Finding the right size of ID grinding wheels in smallish diameters has been a bit of am ordeal so it might actually be easier to make spindles to match the ones I can get. Anyway, from what I can determine, the spindles are not hardened & re-ground. Personally I'd be a little leary of introducing any run out in them from quenching drill rod, but recognize I'm a newbie at all this.

I'm not sure why but wanted to point out they tend to use large face washers on the larger (~3") diameter wheels.

Also FWIW, the typical 0.250" shanked mounted stones tend to have quite different actual shaft diameters depending on which part of Asia they come from (despite what N-Am tool catalog you buy from). They might even be metric like 6mm or something, so just be aware regarding your collet ID.

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...These pre-mounted shanked grinding stones are the ones I was talking about

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petertha said:
Wow you are doing great work. I'm going to make some variants of these Themac extension spindles. Finding the right size of ID grinding wheels in smallish diameters has been a bit of am ordeal so it might actually be easier to make spindles to match the ones I can get. Anyway, from what I can determine, the spindles are not hardened & re-ground. Personally I'd be a little leary of introducing any run out in them from quenching drill rod, but recognize I'm a newbie at all this.

I'm not sure why but wanted to point out they tend to use large face washers on the larger (~3") diameter wheels.

Also FWIW, the typical 0.250" shanked mounted stones tend to have quite different actual shaft diameters depending on which part of Asia they come from (despite what N-Am tool catalog you buy from). They might even be metric like 6mm or something, so just be aware regarding your collet ID.
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I will only harden the spindles if needed and only the end and nut. The shank is heavy enough not to need it. I'm not worried about warping to harden drill rod.

I am using 1 1/8" diameter washers on a 3" wheel. That is plenty big enough unles you intend to run 30,000 to 60,000 rpm. I am running a max of 8,000 rpm. These washers are fine for that speed.

I don't know where you get mounted stones but I buy stones on a .250 +0.000 / -.002 shank. The shank is hard on some of them. They are not metric although the Chinese junk probably is and I have no idea of their quality as I buy a quality stone. There is no point in trying to grind with cheaply made stones. I get good ones from McMaster Carr. .750 diam. .500 or .750 long and will dress to suit me.
 
mark_f said:
I get good ones from McMaster Carr. .750 diam. .500 or .750 long and will dress to suit me.
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That's good to know. I'm familiar with McMaster, unfortunately they don't ship to Canada ...but I have my ways... You are fortunate to have a 1-stop supplier with extensive stock like that.
I'm guessing the 'good ones' might be Radiac or Norton, possibly some other big names. The tool suppliers up here like Travers & KBC carry some of those names, but slim pickins in smaller ID grinding sizes &tend to fill in the spots who knows what from who knows where.

I'll be interested to see your setup & dressing & finish. Here is what I'm doing, liners for model radial IC engine (not chromed or anything, just plain steel or CI).

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mark_f said:
I picked up a DC drive for 1 1/2 hp motor for $28 on eBay. I got it hooked up today to test run the grinder.
View attachment 131321
It runs good after tweaking the bearing preload. I gotta get the belt guard done . This thing scares the crap outta me at 8000 rpm. Also got to get a small box to mount the drive in. It is getting close to ready to use.
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I have the same motor, can you post the ebay link to the drive (motor controller)??
Also curious if you've had any problems with the motor heating since you didn't go with a cooling fan?
 
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