Tool Changer Ready, Spigot-less High Speed Spindle
In this trick we show how we used a simple die grinder to make a high speed spindle for light duty work. It saves wear and tear on the main spinde and prepares us for micro-machining.22,000 RPM on a Budget...
This idea was born as an attempt to engrave using the CNC (See here for that story) but what we wound up with was a tool that works better for light plastic machining. The idea is very simple, machine an adapter to get a die grinder body in a CAT 40 adapter and you have a high speed spindle for your machine tool. (Getting the air to it is a bit tougher, See here to learn how).
The photo shows our prototype. It's made from a old Blue-Point die grinder and a CAT 40 boring bar blank. We've made another version that consists of an aluminum body that mates to a 1" face mill adapter. It has a long offset and the air path was too restrictive to allow full speed and torque. It works but I'm not satified with it.
Some Action Shots...
Here we are machining some electronics enclosures for Zanthic Technologies.
These are some light switch covers that were modified for Zanthic Technologies. Note that we are using the high speed spindle that is adapated to the face mill holder.
I'm very pleased with the plastic work we have been doing with these spindles. My Okuma's top speed is 8000 RPM and it is too slow for the small cutters in light plastic; the high speed spindle does a nicer job. The other thing I like is that the light plastic jobs are generally not big dollar jobs where machine costs can be recovered easily. Using the air spindle saves us from running the CNC at full tilt for hours, which saves on wear and tear of the main spindle.
While these spindle works well on plastic they are not rigid enough to tackle steel, except for deburing work. You also have to be careful that the cutting loads don't stall out your spindle or you will certainly break the tool. For that reason I have not attempted any aluminum work yet. I have got a high torque die grinder that has a large spindle bearing and may work on metals. I will post the results when I get a chance.
Like I mentioned earlier, the high speed spindle that was adapted to a face mill holder did not work all that well. Porting in the air and diverting the exhaust is a bit tricky. From the experimenting I have done, it looks like front exhaust motors will be easier to adapt. I will post new tools as I do them. I also have a 3/8, right angle drill in the works right now. If I ever get that done it will show up on one of these pages too.