Official Luthiers Forum!

....just a heads up on an an almost unbeatable deal for a high speed micro air grinder this week at Princess Auto...... $20
http://www.princessauto.com/air/air-too ... ie-grinder
Not a top of the line unit, but worth a try. (Fred Tellier made me aware of it, and the base he built for it, a few months ago)

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Dave
Milton, ON

At 54,000 rpms, could it be used like a router? (like we have seen in one of those rosette cutter bases)

Mike

I have only used mine for inlay with a small diameter carbide cutter but it should turn at least a 3/32 cutter. They say it uses 2 cfm of air but for steady work it needs at least 4 or 5 or it will slow down. I used one of the inline water trap filters as used for spray painting between the compressor hose and the grinder hose.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

This unit is very like the low end die grinder John Hall supplies with his mini router base. (He also sells a more expensive unit for a bit more $) It is great for inlay, but I don't think it'll have enough torque for a binding cutter

That's my intent, for inlay work.... alternate to a dremel (1/8" collet) with better speed and hopefully less runout. (I think a lot of guys use this type of thing). At that price, you could set one up in a precision rosette cutter base & leave there!

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Dave
Milton, ON

I bought a similar grinder from another firm and it was supposed to be upgraded with better bearings. The run-out on the grinder was huge. Something like 1/32" or so. This made the tool unusable and it ended up in the trash.

I used a similarly priced version and attached it to my sherline cnc for engraving in aluminum. It was all about feed rate and depth of cut, there is not a bunch of torque there. There was some runout but not much. I used a very small ball mill and had to take very shallow cuts (ie. .005).

Devin

We stopped using that die grinder a while ago. the runout on the shaft is a bit off but I think it will at least work for what you need. They are designed to work metal. I use souix and enco but we had to change since enco discontinued them. We use a medium grade pencil grinder as that is plenty of power for what we do.
That will turn the bit very well.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

UPDATE.... after Barry's post I unwrapped it & jigged to check runout.
RUNOUT NOT GOOD! (... about .014" at 1/4" from collet.... my old dremel is only .010")
I apologize ... serves me right for being so cheap!
As Anna Rosanna Danna would say...."never mind"

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Dave
Milton, ON

Dont worry Dave, this is the perfect opportunity for you to get into home dentistry.

Take it back and get another, or get your money back. They will exchange or refund, I have auditioned a few tools from them until I got a good one, but my grinder was quite tight on the run out. Actually I think that for free hand inlay the run out is not as critical as cutting a rosette though yours is a little much.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I replaced my "piece of crap" import tool with a really nice air die grinder from Air Turbine Tools in Florida (bought through McMaster-Carr). It is a very quite tool that runs at 65k rpm and it has zero run out. Not cheap but it sure is nice.

http://www.airturbinetools.com/ht/ss/201SV.html

Barry, are you talking about Style M? http://www.mcmaster.com/#die-grinders/=81o015

I was also looking at the Souix as well...

Mike

I had the Harbor frieght cheapo for my Ellipsograph soundhole prototype. I ran it for about 10 minutes and the runout on it just vibrated everything. The collet even came loose and then it started to leak. Wrapped it up and took it back and called John Hall for the Sioux 70K and it's sweet. I won't mess with the cheap things anymore. The cheap one did just what I thought it would do but thought I'd give it a look.

Mike,

Yes its the style M. Like I said, expensive, but it is a very sweet tool. I use it in a Stew-Mac base for basic inlay work, and I also use it in a pantograph for template guided cutting of wood and shell.

I got to meet Harry Flieshman in Arcata a few weeks ago. He gave a talk on getting started building a guitar. One of the things he talked about were cheap routers with bad bearings. His trick is to buy way more then you need and test them all. His test was to turn it on and gently bump it listening for the sound change when running, if the sound does not change, it has good bearings, on harbor freight tools he said out of 20, he may find 4 that are usable. Seems like too much work to be cheap to me, and I love being frugal.
I know they are pricey, but my Foredom is a great tool, very easy to mount into a jig, replacement handsets start at $40, bearings are good on the one I have. Pictured in the micro fence jig modified to do rosettes, the handset is exactly 1".

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Air tools will run rings around the foredom but you do need a good air compressor. A cutter spinning at 70,000 rpm makes for light work . I agree , buy the best tool you can afford . Buying cheap means you buy again .

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

http://www.toolfetch.com/air-die-grinde ... 4200.shtml (Master Power Pencil Grinder)

Anybody have a feel for this item? Compared to the Souix?

How about bearing runout?

Mike

Well it's twice the price of the 70K Souix. And it looks like it uses 4X as much CFM of air as the Souix if those numbers are correct.

Yes Chris, but I found one "almost new" for $125. I was just wondering if it was a "better" tool.

Mike

I don't see how 8CFM @90psi would make it better unless you have that large of a compressor. See if that person will let you give it a test drive?

I have done some research. 5.3 cfm is an average (Souix) and it can go as high as 21 cfm (http://www.powertool-box.com/product.ph ... 527&page=2) but I would assume the same is true for Master Power.

What I am really interested in is the bearing runout, quality, etc.

Mike

A lot of the air specifications given by tool manufacturers are way too high. In real use, the air consumption can be much less than they state. There is no way that little grinder uses that much air.

Interesting. I bought one of the Harbour Freight things years ago and it was dead on w/o runout and quiet. I immediately bought another for backup, I think they were only ~$12us at that time. I made my own little micro-router base for it and usually run it at only ~60psi with dental bits and that is just fine for any inlay work I do. I've taken to using it for cutting out my shell inlay too. It eats a bit more material but for where you don't have to match edges it is fast and easy. I hand hold it to clean up inlay edges. I'm still on the first one and never did need to go to the second backup tool. Maybe the quality has deteriorated these days or I just hit a good batch.

Alan D.