Why didn't I think of this a long time ago?
I tried the idea described in my last post, to use "Dremel" type attachments on a pneumatic die grinder air tool. First, here are examples of the type of tools I'm referring to:
They come in a large array of configurations, many of which are not shown in that pic. For the most part they use a standardized 1/4" "callet" to attach various cutting bits, etc. A couple of the tools I have came with a second 1/8" callet, which I've never thought to use for anything. So I decided to swap to the smaller callet and see if the assortment of rotary (Dremel) attachments would work. Here are pics of what I'm talking about:
The callet is secured into the end of the tool by the same threaded collar that locks the bits in place...
They simply slide in and out of the tool.
Here are the smaller 1/8" and standard 1/4" callets...
I'm sure replacement 1/8" callets are readily available for very little money. And since they are a universal fit you really only need one to use with any of the air tools you might already have. Frankly you could buy a new pneumatic tool for the price of a Dremel these days.
By simply swapping the callets, you can mount any of the little rotary attachments (bits) to the pneumatic tool...
I gave it a try and it works well. The speed of the tool is controlled by the air flow. So you can regulate the air pressure or use the 'trigger' on the tool to adjust the speed. By limiting the regulator pressure a bit, the maximum speed is kept to a safe level for these small bits - regardless of trigger position. And by toggling the trigger position the speed can be varied on the fly. This makes the speed even more variable than with the adjustable-speed Dremels. The overall pneumatic tool size is about the same as a Dremel. However the air hose is more restrictive that the power cord on a Dremel. And certainly more than a "cordless" Dremel (which I prefer
not to use simply because I already have way too many rechargeable tools around my shop - read as 'lots of chargers' everywhere). I haven't tried the "whip" hose yet to see how much more maneuverable that makes it. The whip is a very flexible, lightweight section of air hose with a "swivel" on the end:
Another thing about the pneumatic tool is the trigger needs to be held while using the tool. One of the common benefits of a Dremel is the ability to do very fine work in tight places. That often requires some 'finesse' with holding the tool. In the case of the pneumatic tool I suppose the trigger could by tied down (i.e. a zip tie) and the speed controlled solely by air pressure. Perhaps a small regulator or control valve at the other end of the whip hose might be good.
Considering the way array of pneumatic die grinders available, this concept will provide a much larger choice of configurations than a Dremel can. I will use this setup in the future to see how it compares to using a Dremel. But it would be a great alternative if it works out. Why didn't I think of it before?