Electric die grinder question

Hello gents,
Quick question..... Is there any problem using a variable speed controller on an 110VAC die grinder? The problem I'm having is all mine are
24-30k RPM and I need to run much slower for doing cylinder head porting with abrasive wheels and discs. I normally use air tools for this but my compressor makes more noise than air and it's a big drain on the wallet to run. If this is ok to do can you recommend a suitable unit. A dial or foot pedal is fine. I just don't want to fry the brushes or unit all together. Electric stuff is not my forte so I figured I better ask first.
Thanks as usual!
Rob
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Well, hi, Rob!
Long time no read, group and groupies!
Sure, you can use a variable speed controller on a 110 VAC die grinder. I have one made by HF used with their trim router, and that controller can dim 15 amps. However, it's a crap controller. There is no "IR compensation" to keep the router speed constant when the mechanical load changes. You'd need a much more expensive control, stating a speed/load regulation in percent to determine if you can get the critical cross hatch hone pattner needed for healthy engine bores.
You'll fry brushes and commutator with such a cheap controller when you stall the unit with a honing load at low RPM.
My trim router adapts to my Smithy Super Shop's four-way toolpost using cuts I made into the cubical post body of cast iron. I used a milling cutter (a 45 degree dovetail cutter) that had the same radius as the trim router body. IIRC t his was a 2-3/4 diameter. I then used fence by hand to cut three slots in the post body for hose clamps, so the router is held by two clamps in radial position and one clamp when in paraxial position. I like it! I've got the 1/4 inch body center drill, a selection of 1/4 shank router bits and grinding stones, and a cutoff wheel and arbor.to work with the trim router's collet.
So, who here can recommend a router speed control with stable performance and IR compensation at crawling speeds?
Doug Goncz Replikon Research Seven Corners, VA 22044-0394
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snipped-for-privacy@alum.mit.edu wrote:

Doug , he was talking about porting work on the heads , not cylinder honing . I used a dremel unit to clean up the ports in a set of motorcycle heads ... it was slow and underpowered but it worked . A Foredom type unit with flex cable drive should be just what the doctor ordered , and IIRC they have a built in speed control . Might cost more than just a controller though .
--

Snag aka OSG #1
'90 Ultra , "Strider"
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That's the problem. All porting is done with 1/4" shank bits and mills. I do indeed use a cabled Dremel for intricate work and I'd be lost without it. for the big removal it's up to the big-dogs. I prefer my Dewalt# 887 and a Makita of the same size. When on the compressor, I have six or seven grinders that I leave chucked up with the bit I'll be needing rather than swapping tooling. I bought a bunch of the 887's and they have little vibration and I'm able to feel my work really well but they just spin too fast. I should have been more clear... Sorry about that.. The heads are Iron but mostly Aluminum. BTW for the record, my Dremel is about three years old. I use it about twice a week in what would be easily considered "above duty cycle" (and then some!) That tool has been abused big-time. I tear it down regularly and lube the cable and clean it up and it just keeps working and working.... By rights, that tool should have died a long time ago. That is how tools SHOULD be made!
Thanks again,
Rob
Fraser Competition Engines Chicago, IL.

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I'd suggest one of the big (1/3 hp TX, TXH) Foredoms (15,000 RPM top speed) unless you want lower top speed (5000RPM) with less power (1/12 hp L series).
You could try one of the Foredom heavy-duty speed controls on your current grinders, I'd guess, as being probably better than harbor freight, et al, if the current rating for your grinders is less than the current rating of the Foredom the speed control is made for. But you might want to just get a set and go, if you're using it that much. They are good.
--
Cats, coffee, chocolate...vices to live by

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Any over the counter Grainger type will work? Very good news. Should I expect to replace brushes more often as a result? If so, I'll just stock up. Is there any model in particular you would use if in my shoes?
Thanks again!!
Rob
Fraser Competition Engines Chicago, IL.
wrote:

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You might try to find a dremel foot control, they are great for your application. I use one with my Makita for porting. Unfortunately I believe Dremel dropped the foot pedal now that they build the speed control into the tool. foot pedal controllers.

do
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