Thread: Why you need an air micro die grinder

Yes awesome bits of gear...

Also what do you measure with that ruler?

Originally Posted by .RC.

Yes awesome bits of gear...

Also what do you measure with that ruler?

It's a special computer measure.

You use it to measure Wangs

They're similar to wongs.

Rob

Hi Rob,

I have been looking at the diamond burrs for these little grinders and wondering what grit size you use.
The burrs appear to be offered in 40g (coarse), 120g (medium) and 300g (fine).
I would assume that 40g is just a tad coarse and guess that 120g would be the best all round.
Interested to hear what you have found.
Love your videos!
I first came across your web pages re setting up your lathe for milling and found the information very helpful as I have the same chinese vertical milling attachment.
It wasn't quite as easy to set up on my AL320G lathe due to the stepped cross slide, but I got there in the end.

Cheers,
Alan

How does the diamond burrs wear without water lubrication? I know diamond tools works well on stones and granites but does diamond work as well on metal?

Becareful when using stones grinding wheel on your lathe, clean your ways or protect them from the abrasive deposits. I am guessing diamond tools is best as they wear slowly and result in less deposit?

Originally Posted by OLCDOG

Hi Rob,

I have been looking at the diamond burrs for these little grinders and wondering what grit size you use.
The burrs appear to be offered in 40g (coarse), 120g (medium) and 300g (fine).
I would assume that 40g is just a tad coarse and guess that 120g would be the best all round.
Interested to hear what you have found.

Cheers,
Alan

Wow, you got me there Alan - it's been a while since I bought my diamond burrs and the plastic boxes don't say the grade.

I'm pretty sure they are all 120 grit, as that is the most common type available and that was what I went for - cheap too .

I don't have any coarse ones. When using diamond you are generally aiming for a good finish - 300 grit would be a bit slow.

Glad you enjoyed the videos - started out with a few and it seems to have got a bit out of control.

Oh well that's life.

Rob

Originally Posted by forp

How does the diamond burrs wear without water lubrication? I know diamond tools works well on stones and granites but does diamond work as well on metal?

Becareful when using stones grinding wheel on your lathe, clean your ways or protect them from the abrasive deposits. I am guessing diamond tools is best as they wear slowly and result in less deposit?

I'm still using my original diamond burrs and they aren't showing any significant signs of wear. They seem to last pretty well, and you get lots for your money.

I use them dry.

They would probably stuff up if you used them on soft alloy/materials as they would clog - same as a grind stone.

They work best on really hard stuff like steel, weld, ceramic, glass etc and are relatively self cleaning at high RPM.

Diamond burrs don't tear themselves apart like an emery wheel, so any deposits will be the material you are working.

Cheers

Rob

The Micro Grinder was purchased at Bunnings - Maitland - $24.00 reduced for clearance. Had Been marked down several times.
It was also available at Bunnings - Belmont NSW. They have just done a stocktake and are clearing various items. Maybe it will happen at various times at other stores. Maitland had at least four more units available, Belmont had only one that I could see. I would rush out soon an check a number of stores.
Show them this photo.

Good Luck,
regards Ned

Note - they were in tool section - on shelf - with orange tag - not out on display!

Good pick up at that price.

Two things worth a mention if you use the die grinder in a rigid mount (as a mini TPG):

- Make sure you eliminate shank whip and vibration by keeping the tooling overhang/shaft length as short as practical. Do the spare collet modification I mention in my blog if using 1/8" burrs.

- to the right of the barrel air control is a small allen screw under the exhaust tube. This locks the end section which (if I remember correctly) unscrews to allow disassembly. Both can work loose if vibration occurs. I loctited it in.

If you pay attention to these points you won't have any vibration/flex issues - as shown in the video.

Cheers

Rob

Originally Posted by nearnexus

Good pick up at that price.

Two things worth a mention if you use the die grinder in a rigid mount (as a mini TPG):

- Make sure you eliminate shank whip and vibration by keeping the tooling overhang/shaft length as short as practical. Do the spare collet modification I mention in my blog if using 1/8" burrs.

- to the right of the barrel air control is a small allen screw under the exhaust tube. This locks the end section which (if I remember correctly) unscrews to allow disassembly. Both can work loose if vibration occurs. I loctited it in.

If you pay attention to these points you won't have any vibration/flex issues - as shown in the video.

Cheers

Rob

Can you point me in the right direction for this blog entry Rob. When I looked at your blog I found only one entry which was not the one.

Dean

Originally Posted by Oldneweng

Can you point me in the right direction for this blog entry Rob. When I looked at your blog I found only one entry which was not the one.

Dean

Air micro die grinder

and for the collet mod (a simple modification):

Air micro die grinder

Cheers

Rob

Originally Posted by nearnexus

Air micro die grinder

and for the collet mod (a simple modification):

Air micro die grinder

Cheers

Rob

Thanks Rob. Very interesting reading. I will look into the collet modification and the air cooling tower. I wonder if the dremel collets will fit?

Dean

Originally Posted by Oldneweng

Thanks Rob. Very interesting reading. I will look into the collet modification and the air cooling tower. I wonder if the dremel collets will fit?

Dean

I don't know if they do fit Dean. Let me know what you discover.

The collets are pretty simple and would be easy to make if need be.

Also you may want to look at the blog again as I just added a bit more info on two more modifications worth doing. ie the Allen bolt/ Loctite and a hose clip.

Cheers

Rob

Originally Posted by nearnexus

I don't know if they do fit Dean. Let me know what you discover.

The collets are pretty simple and would be easy to make if need be.

Also you may want to look at the blog again as I just added a bit more info on two more modifications worth doing. ie the Allen bolt/ Loctite and a hose clip.

Cheers

Rob

The reason I was wondering about the dremels collets fitting is that I have a number of different sized collets to fit the dremel. Two sets I think from 1/32 to 1/8. I also have a lot of bits to fit as well, which are also 1/8. I have the same issue with these not fitting into the 3mm collet of the die grinder.

The dremel collets do fit in the die grinder which may be useful.

You said in your blog that you drilled out the spare collet and it was made of brass. I did not get a spare collet (or oil but I got the little bottle) and my collet is made from hardened steel. You mentioned axial runout. My collet appears to be ground to size and has a raised diam for about the last 4mm. This appears to be a close fit inside the drive shaft. The dremel collets of course don't have this raised section which means they may suffer from axial runout.

Dean

Hi Dean,

That's great information. You don't know how hard it is to get people to contribute to the web. I will incorporate that into the pages.

The fact that a Dremel collet will fit is actually a big deal. What it means is that if the collet in the die grinder stuffs up, you can get a Dremel as a replacement. Trying to get an OEM die grinder part would be very difficult.

So all this information is actually quite valuable.

To modify a hardened collet you could use the die grinder and a smaller diamond burr as in my video to do the job. Once again, this sort of work would be near impossible any other way.

These units are really very useful for this sort of work.

Here's a shot of my 3 mm collet (unmodified).

collet.jpg

Have you checked yours with a magnet to see if it is steel ?

The radial runout is not massive, but I did detect some given the basic style/fit of the collet.

Cheers

Rob