# Using a Dremel on a lathe



## prasad (Dec 5, 2014)

Guys, 

I recently made a Dremel tool holder and I tried to use it as a grinder. I see two possibilities. I am not sure which one will be the best. 

1. Mount the Dremel on the tool post, adjust the compound to the necessary angle and then feed the Dremel tool forward (away from the operator) just as you would if it was a regular cutting tool.

2. Mount the Dremel tool and place it behind the part being machined and bring Dremel towards you (towards operator).

Thanks
Prasad
Wynnewood PA


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## Andre (Dec 5, 2014)

Both are incorrect. When toolpost grinding you want the grinding wheel grinding against the material, not rolling on it. Run your lathe in reverse, and point the dremel towards the lathe headstock. The work and grinding wheel should be moving in opposite directions.


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## Bill Gruby (Dec 5, 2014)

Andre is correct, you want the wheel turning against the rotation of the work piece. The Dremel mounts wheel facing the chuck. The spindle on a Dremel runs CCW as you are looking at the wheel end. When this is mounted it will run with the chuck with the lathe running normal. You must reverse the chuck direction to grind material off.

 "Billy G"


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## george wilson (Dec 5, 2014)

A Dremel tool is a VERY poor substitute for a tool post grinder. Their bearings are not even properly seated in their mountings.

You can improve the performance of the Dremel tool by taking the housing in 2 pieces,and exposing the bearings in their seats. Proceed to fill up the empty spaces in the bearing seats with Bondo or J.B. Weld. Be careful to NOT get the filler material onto the side surfaces of the bearings(The shields). You do not want to freeze the bearings up.

Filling up the gaps around the bearings will help a great deal to improve the surfaces you can produce when trying to grind with the Dremel tool. However,the basic quality of the bearings is not the best. High tolerance bearings cost a lot of money. Much more than the Dremel cost.

I have a 1/10 H.P. DUMORE hand held grinder,which is VASTLY better than a Dremel,if you can afford one,or can find a used one that still runs well(meaning the brushes have not gotten so short they overheat the commutator). Brushes can be replaced. Hopefully,there will not be a groove worn into the commutator,though. This can be determined only by taking the grinder apart.

I would submit that a small router,like a Zip Cut(Is that the name?) drywall router,would be a better performer than the Dremel.

Dremels also have a weak plastic connector that connects the armature to the chuck. It has the habit of easily failing at the slightest provocation. Or so it seems. I gave up using a Dremel,and use an old Dumore or an old Fairchild hand grinder I got at a flea market.


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## Rick Leslie (Dec 5, 2014)

My old Southbend will nt run in reverse as currently set up. Consequently, I am forced to grind 'incorrectly'. I can still achieve satisfactory results by running the lathe spindle very slowly and using my little Dumore Tool Post Grinder (30,000 RPM rated). If you must use a Dremel, I would take the tiniest of cuts possible (barely spark off) and set up as in figure 1 (grinder in front of work). This will throw the debris down. The other way will throw grinding dust into the air. Be sure to cover you ways well.

Bear in mind that this is still the incorrect and least desirable way to grind, but if you must, you must.


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## Fabrickator (Dec 5, 2014)

A Foredom also works better than a Dremel being of higher quality w/ an all metal body and 3-jaw chuck.  Here's mine is set-up on a ball turning jig for a special application with a std. 1/2" tool holder.


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## darkzero (Dec 5, 2014)

Seems like people use Dremels with success, mainly the mini lathe guys. I tried a Dremel mounted in the tool post with one of those holders that screw onto the nose of the Dremel. I never got good results but maybe I was doing it wrong.

As said the Dremels don't have precision bearings & the bearing seats aren't that great. The plastic housing flexes as well, especially where the nose threads are. That's not to say it can't be done though as it has.

I was going to use an electric die grinder with a metal housing or one of those pencil air grinders. Better than a Dremel that's for sure. I ended up scoring a Dumore tool post grinder for cheap. It's their smallest model but it's way better than a rotary tool.


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## george wilson (Dec 5, 2014)

Back in the 70's there was an article in Fine Woodworking about improving the Dremel's performance by packing the bearing housings snugly. It made a big difference.


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## Andre (Dec 5, 2014)

You should really use a air pencil grinder, they are 100x better than dremels. And that don't have that gyroscopic affect dremels have either.

They are faster, more accurate, collets are better, and actually quieter. Their cheaper too! Mine was $30 with in line lubricator and air chuck quick connect.


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## george wilson (Dec 5, 2014)

Agreed on the pencil grinder. Get a small one unless you have a LARRRRRGE air compressor.


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## Frank Ford (Dec 6, 2014)

Here's a  link to my little photo article on upgrading the bearing mounts on a Dremel - I used shrink tubing, and while it helped quite a bit, the housing itself is so flexible that the Dremel still leaves much to be desired:

http://www.frets.com/FretsPages/Luthier/Tools/DremelBearing/drembear.html


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## road (Dec 6, 2014)

Here is a pic of a damaged Dremel from tool post grinding.    it was less than 3 months old. 

It's fixed but I'll never use it on a lathe again.  

I know the older versions of Dremel tools were direct drive.  I have had 5 types dremel's or copies over the last 15 years, my original Dremel is the only one that has lasted. 

I have modded some of them with j-b and stronger plastic drive connection sleeves.  

Dremel tools are not the best for harder working pressures as others have said. 

I would use a Grobet rotory tool or an air pencil grinder / some thing like it.


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## Eddyde (Dec 6, 2014)

The Dremel is more of a toy than a tool, suited only for the balsa, plastic model maker or similar craft-hobby crowd. It has no place in a metal or wood shop.
The pencil grinder is an option only if you have sufficent compressed air to run it, they are rather loud too. I recommend using an electric  Die Grinder, they are available from most major tool manufactures and are 1000x better than a Dremel. Most have a rather long straight barrel before the chuck, making an attachment fixture for a lathe easy to fabricate. You can even clamp it into a milling attachment if you have one. One important thing to remember: Abrasive dust will rapidly destroy the ways of your lathe. You should take great care to protect them. Cover the ways with aluminum foil and position a vacuum nozzle to catch most of the dust while grinding. I have gotten exellent results with such an arrangement.


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## rgray (Dec 6, 2014)

> A Foredom also works better than a Dremel being of higher quality w/ an all metal body and 3-jaw chuck. Here's mine is set-up on a ball turning jig for a special application with a std. 1/2" tool holder.



Those foredom ends also fit right in a QCTP BXA boring bar holder (the large one) with the sleeve removed.


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## Dunc1 (Dec 6, 2014)

Beyond using a Dremel there are some d-i-y plans:
Popular Mechanics, Aug 1944; Popular Science, Aug 1941.

Couple of How-To Use: Popular Mechanics, Feb 1944 & Nov 1949

There are plans (maybe) floating around the 'net reprinted from Model Craftsman, June 1937. Author is CW Woodson. This one requires a casting.

Try checking the archives of Home Model Engine Machinist (HMEM). I have a brief reference to a thread but unfortunately no url.

Little Machine Shop (usual disclaimers) sells a few models.


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## David Kirtley (Dec 6, 2014)

Rather than a Dremel, I use a Proxxon Rotary tool. Not even in the same league as a Dremel. They actually make toolpost holders for it. Quiet and basically no vibration.


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## Andre (Dec 6, 2014)

You can make your own TP grinder, there is a magazine article I have on building precision bearing machine spindles and if you want I'll send them on.


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## Andre (Dec 6, 2014)

george wilson said:


> Agreed on the pencil grinder. Get a small one unless you have a LARRRRRGE air compressor.




Very true, my 60 gallon pumps every minute or so using it. But when you need a pencil grinder, it's the only tool that will work.


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## Bill C. (Dec 6, 2014)

prasad said:


> Guys,
> 
> I recently made a Dremel tool holder and I tried to use it as a grinder. I see two possibilities. I am not sure which one will be the best.
> 
> ...



I have a Dremel, I use as a BSA Pinewood axle polisher.  It has the RPMs but I doubt the torque needed for fine grinding. Use the Dremel sparingly.  I would recommend a electric tool post grinder for your lathe if your budget can handle it.  

Best of luck


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## Rick Leslie (Dec 7, 2014)

If the Dremel is all you have and you can make due, then by all means use it. Just don't expect a ground quality finish. More like a 'grinder' quality finish. 

Building a tool post grinder would be an awesome project for you as well. Lots of info available on shop made units to follow.


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## ki4byz (Dec 7, 2014)

I used my HF air pencil grinder to grind the ID taper of my er40 holder when I built it.

  It worked well, but I could only take about .0005 cuts.


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## Chips4Lips (Dec 7, 2014)

Everyone typically uses the best tool they have available and if it's a Dremel, then that's what it is.  I've been trying to gain some advantages in miling and on a lathe for a small high-speed grinder and have probably tried "too many" to be proud of.  The "better option" in the small sized "non-professional" version has been a Proxxon grinder - it has better bearings and they are supported by a metal frame rather than being plastic that is more prone to flexing and softening with temperatures.  Compared to Dremel tools it is almost double the money but is worth it to me.  The pencil grinders also come in a few varieties of "quality" as do most things and while they do not have bearings intended for this use, they will work but don't equate the size to minimal air flow.  In order to get the rpm and torque, you have to open up the valve and use more air.  I've found one other item made for more of this purpose - called a "Mini-Mac - MM625."  You'll have to take your extra wallet to pick it up but this device is also air driven, 30k rpm, small shaft size limit and actually has the bearings and construction that you're wanting in a small package that's for more of the pro-use.

The answer to everyones question is really about what you are trying to achieve - 1 part per year or 100 parts an hour for the next 5 years?  That's where the money question gets resolved as will your options for the best tool for the job at that time.

Have to comment on an earlier reply in this group from "Mr. Ford" - if you haven't seen his website before, you should set aside a few hours to look it over closely.  I've not seen anyone's site with as much value in what he shows, the subjects he picks, the methods he comes up with and his consistent photographic attention to details.  He has more "damn good ideas" than most ever manage to come up with and he's offering it to you for free.  He has a specific line of work that creates the need for "inventiveness and creative thinking" and he does both consistently.  Don't miss the chance to learn something from him and I know you will in the first five minutes!

Thanks.


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