Making a small collet for a "Precise" hand grinder? (plus tool gloat)

[gellfex]

I had a recent score of 2 of these grinders, apparently they're what Dremels want to be when they grow up. A neighbor found them clearing someone's basement and they were mine for $20. Unfortunately they've both got 1/8 collets, and this device is pretty obscure, though highly thought of in the few references I found, including a couple of post where people paid hundreds just for the collets! But the name of the damn mfr, Precise, makes it almost impossible to get good search results. HSM's search engine throws the term away as too common!

I'd really like some 3/16 & 1/4 collets, and it looks like I'll need to make them. Any advice on what steel alloy, and what, if any, treatment is needed? I have a .020 slotting saw that should do the trick after the lathe part. I suppose I'll have to make some kind of indexing block for it, don't yet have any indexing equipment.

For the curious, these would be useful for renovation work, where I do not have a compressor with the CFM for an air die grinder. I used one today with a 1.25 cutoff wheel on a toilet mount screw that was too high. Cut it like butter. I also have extensively used my Dremel with a small sanding drum to cope MDF moldings. Much faster than a coping saw and rasp.

[strokersix]

I would use 1144 sometimes known as "stressproof". no heat treat required and machines nicely. It won't be as durable as a real hardened collet but maybe it's good enough.

[Duffy]

Are you sure that a set of collets from HF that fit a lot of these small "Dremel-like" grinders wont work? They are usually brass and cost a couple of bucks-worth a try.

[Jess13]

That may be the same collet that the Proxxon grinders use, it sure looks like it.


Jess

[Optics Curmudgeon]

Try googling "fischer precise collets" and see if anything looks familiar. I found this: http://shop.fischerprecise.com/Accessories/Collets

[dian]

didnt gellfex say 3/16? dremmel and proxxon go up to 3.2 mm. i would make them out of silver steel. but check a router collet first.

[macona]

Unless you are going to harden and grind them there is no point in silver steel. Stick with something that will leave a nice of a finish as possible. 12L14, 1144, maybe even pre hard 4140. Heck you could even use bronze or brass. I have seen collets like this made from that before.

[oxford]

Me personally, I would be looking to see if I could adapt a flex shaft with a pencil type end on to the grinder. Just pick one that uses that size collets you want. I find the flex shafts are much easier to use than holding the power head in your hand.

[Toolhawk]

Precise grinder

You can still buy collets for that grinder from Precise but are very expensive! Be very carful with that tool as it is not a toy. Use only Precise bits as Dremal and HF bits can bend 90 degrees when you turn the grinder on due to high speed and torque. I have seen some bad injuries with these grinders and had a few close calls myself. Don't even think about attaching a flex shaft to it. That grinder turns 44,000 rpms the instance you flip the switch. If there is any run out or out of balance in the bits they can fly apart. You can buy collets direct from Precise at. ------- Precise Corp. 3715 Blue River rd. Racine WI. 262-632-6173 53405
That is one of best grinders ever made and you will love it but be carefull with it.
By now you are probably thinking what is the big deal some air grinders turn 115,000 rpms with low cost bits, the difference is they start up slow then gradually reach there high speed, it is not instance like the Precise grinder.
George

[DR]

That's not a Precise grinder I'm familiar with, neither is that style of collet. I have a hand held Precise grinder and two Precise spindles meant for machine mounting that all use the same short collet, not at all like the collet shown. Luckily, I have collets since they're well over a hundred bucks per at last check ten years ago.

Is this a 40,000 rpm grinder? Or, is it a lesser "hobby" type? My hand held unit uses a separate bearing cartridge to hold the bits, which in turn is driven through a coupling to the motor, the one pictured doesn't appear that way. At one time I picked up a hand held Precise grinder at an estate sale, plastic body, much, much less quality than I'd ever seen, noisy and vibrated badly.

BTW, I enquired about having new bearings factory installed in one of my Precise spindles, it was several thousand and that was way back in the day. Obviously, they're very proud of their products.

[Toolhawk]

DR. The grinder in the picture looks like a upgraded Super 30 like the one I have that was made about 1960, the collets are not the same as the ones that fit in the fixture mounted grinders. I have a old tool post grinder made by Precise that takes a larger collet, I have a full set of collets for both grinders. BTW my late uncle designed the Super 30 in the late 50's for Precise so I have a soft spot for there products. I can't imagine them making a cheap grinder using plastic but the way things are today who knows. As I remember the bearings used in there spindles were class 7 so a rebuild would be very expensive.
George

[J. R. Williams]

Many "Dremel" collets are made of Aluminum.

[DR]

DR. The grinder in the picture looks like a upgraded Super 30 like the one I have that was made about 1960, the collets are not the same as the ones that fit in the fixture mounted grinders. I have a old tool post grinder made by Precise that takes a larger collet, I have a full set of collets for both grinders. BTW my late uncle designed the Super 30 in the late 50's for Precise so I have a soft spot for there products. I can't imagine them making a cheap grinder using plastic but the way things are today who knows. As I remember the bearings used in there spindles were class 7 so a rebuild would be very expensive.
George

Very interesting.

My hand held unit may be a Super 30 (that name sound familiar, it's in my storage or I'd take a look). The spindles have a bracket to mount in place of a lathe toolpost for ID grinding. One of the spindles came out of a circuit board drilling machine. I thought they all used the same collet, but come to think about I'm not sure I ever interchanged them. From memory the collets are simple tapered split ring type maybe 3/8" max diameter by 3/8" to 1/2" long.

The spindles have a small Fram air filter on the top end.

The spindles are heavy, all steel/iron construction while the hand held is polished aluminum and much lighter.

You know, the one I had that I said was plastic may have been Bakelite.