Rotary Tool suitable for modelling?

You want a low voltage hobby drill, from Minicraft, Rotacraft or Expo for instance.

I have two possibilities.

1) I bought a cheap rotary tool from Harbor freight (cost - about ten bucks on sale, including a number of bits and extra chucks). It's a lot slower than a Dremal and useful for small work. 2) I also have a pistol-grip electric screwdriver which I jury-rigged a chuck for. I use this one for slow and precise drilling on models. Bought it at Lowe's for around thirty bucks, although its primary use is still screwing in carpentry.

Regards, John Braungart

km wrote the following on 9/26/2012 4:33 AM (ET):

Depending upon how many holes you want to drill and the material to be drilled, a pin vise might work.

I opened up all of the flood holes in the deck of my 1/72 Revell Type VII u-boat using a drill/pin vise and the back side of an X-Acto...

...I was also hopped up on prednisone and fighting hallucinations at the time...

Thanks everyone.

I have ordered a Minicraft with transformer that allows 0-30,000 revs

km

The Minicraft Kit arrived today - actually ordered it yesterday on EBay from a company called Rapid Electronics. Exceptional delivery service.

Unfortunately on setting up the drill I find that, although the advert says 0-30,000 rpm range, the transformer coming with the kit works at

5,000 - 30,000rpm. The transformer number is 82012 but the product specification details indicates that Transformer MB751 is the one neede to give the lower speeds. I can find nothing for this on Google searches.

I have e-mailed the Company to find out how I can achieve the performance quoted in the advert.

Proxxon have a variable transformer for the Micromot range (Transformer No. NG 2/E) I wonder whether the Maxicraft Tool will fit this and whether that will go down to zero. The adverts don't give that detail and the web site for Proxxon gives no contact info.

Anyone got any suggestions?

km

For "Maxicraft" read Minicraft

km

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I've got the same drill but I run it off a generic variable supply. In the old days we'd use the supply from a model railway, enough power for what we need and good control at the low speed end.

You will find that the drill will slow down under load, but I know exactly what you mean about it being too fast for plastic, as the tendency is for the tool (drill, saw or cutter) to melt rather than cut the material.

There's a listing for the MB751 here

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Thanks for your response Alan.

The link doesn't appear in your message, can you post it again?

I await a response from the seller before deciding what to do. I am wary of making adjustments to the tool ie rewiring the plug that goes into the current transformer, until I see what they say.

I will probably keep the Kit no matter what the outcome as I have a Dremel and a B&Q cheapo Rotary tool that I use for DIY. This Minicraft looks and feels just right for modelling if I can get some alternative transformer that does the job.

During my research I saw the Dremel Fortiflex which looks good but is at a pricey £200+

km

grr, Thunderbird posted that for me prematurely. The listing for the MB751 here

says it goes down to 0V output which is what you want for control down to zero rotation.

The Proxxon device is using similar electronic output control but does not say if it goes down to 0V.

Thanks, at least its an option, even if in USA.

The Proxxon transformer just raises that doubt doesn't it? The various sellers don't cover the point about 0 speed. No doubt they would simply say it depends on the drill that is attached but I don't want to accumulate a series of kits and will seek a definitive answer before buying. (Which is what I thought I had when buying from Rapid).

After Rapid reply I will follow up with Proxxon.

Thanks for your help.

km

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Out of the other supplies that Rapid list, the more expensive Maxicraft also only goes down to 3V so is unlikely to be any better than the small one.

It doesn't help, but I have an Aldi-special-offer drill (bought for my son) that goes down to zero using just a dial on the drill body itself. Never seen it advertised again though, and its branded Powercraft which is Aldi's own-brand name.

I've looked at the tool and its handbook and discovered it's source was Walter Werkzeuge. Further searching found this listing.

which is the same tool. It comes with an 18V power supply (a black brick :) ) and some (pretty poor) tools. But I can tell you for certain that the tool I bought from Aldi that looks exactly like this one goes down to zero speed.

They would be dodging the issue if they say it depends on the drill, we're talking about DC drills here and their speed is set by the power supply - after all, that's what they are selling, a variable speed supply.

I would not trust the Proxxon to go down to 0V without checking its spec sheet. It's much easier to make a 3V-18V supply than a 0V-18V one, there needs to be good current regulation and better components to avoid burning out your supply. As volts approach zero, current demand from a simple resistive load goes towards infinity - which without current regulation means the weakest component burns out first.

I've posted a link to the Walter tool above. Sorry I didn't look for that one first - but I've used my Minicraft for years with a supply I lashed up myself. It doesn't go to zero, but goes low enough that I can cut without melting.

The same supply powers my low-melting-point soldering iron, which gets used for soldering white metal components together, using the appropriate solder and flux. It's a little 12V iron, so I can control its temperature easily, quite important with white metal.

Rapid are a big company with a solid reputation - I've used them before

- so you should be able to return the Minicraft kit if it's in a fit state.

That seems to fit the bill. Quotes 0-20,000.

The only drawback seems to be collet rather than chuck but I believe adapters are on the market to fit into a collet and convert. Thinking here of using drills at 0.5mm/1.mm.

This didn't come up in my searches but thats not surprising as I used "rotary tool".

Thanks once again.

I may well get this as well as keep the Minicraft as the outlay is not high.

km

My knowledge of electrics is pretty poor. I do however follow what you are saying.

I will probably keep the Minicraft and buy the Walter tool (see other post).

Any tips about getting an alternative transformer which would make the Minicraft do what I want? No doubt I would need to change the plug connecting to the transformer - small two-pin, or try and find an adapter.

picture here:

km

I model braille armor and most of the time, my stable of several pin vises will do all the drilling I need. However, occasionally I need a motored device. I use a battery-operated pen-style electric screwdriver that runs about 30-40rpm and is very good for carefully drilling through plastic parts (like lightening holes in many road wheels, etc). I got this at Fry's but have also seen it at MicroMark and Lowes'. You will need a special chuck (they also sell) to accomodate your bits but this slow-speed device (anything above 100rpm is probably way too fast for plastic) works pretty well for me. The screwdriver was 20 bucks and the chuck around 10. Good luck.

regards,

======= fredman =======

Thanks for this. I have returned the Minicraft and received a full refund.

Following my searches I did indeed do what you suggested ie bought a cheap chuck holder to fit in a screwdriver that I already had. I also bought a selection of collets and a chuck converter for a small amount.

I had already bought some minute drills so am able to do everything I want.

Because I can see the benefit of a variable drive of 0-20,000+ speed I also went ahead and bought the electric rotary tool from Walter (as suggested by Alan) this arrived and at less than half of the cost of the Minicraft is a bargain. Also it had a selection of the small drills etc!

Thanks to everyone.

km

If you're looking for small drill bits, try this - the next time you go in for a dental appointment, hive on your dentist for any of his/her old bits that are no longer considered usable. They are still plenty good for modeli ng. The last time I did this, I was given a prescription bottle full of ass orted types - free. They were clean, just having been run through the autoc lave to sterilize them (they have to be so to be recycled) and she was glad to get rid of them. And I have enough to last me thne rest of my days.

Regards, John Braungart