After breaking a few 1/16" end mills tonight until I figured out that I had my feed rate set too high I figured out that the spindle on my bridgeport style mill just can't spin fast enough to run a feed rate much higher than 3IPM. My spindle is a quick change 30 taper that spins a max of 3000 RPM. Using the RPM formulas for aluminum recommend a spindle speed in excess of 20k rpm.

I was wondering if anyone has done any kind of 'DIY' project where they attached some other kind of high speed spindle to their bridgeport style mill? I was thinking of clamping something to the spindle. The main thing I am looking at doing with this high speed spindle and 1/16 - 1/32 end mills are engraving text and logos on aluminum parts.

Any ideas would be appreciated!

Thanks,
Brian

How deep are you trying to cut? Yea, I've seen pictures of people basically mounting dremels to the spindle nose for engraving.

I would figure most of the time it would be no more than 1/8". This would basically be for engraving text, etc so I can't imagine needing to go deeper than that. I know the testing I was doing the other day was no more then 0.015 deep and it looked fairly decent.

I use single flute 1/8" router bits, solid carbide 60* angle for part number engraving or even engraving fuel rails and custom motorcycle parts. I only go .005 per pass, .010 total depth at 12ipm on SS and 20imp on aluminum. .010" doesn't sound like much but it's pretty normal for engraving the parts that I do.

If your trying to cut a sign or something, try using a bigger endmill and do a "re-machine" opp with your 1/16". Your using 2 flute, right? And just a blast of air would help you more than a coolant flood in this case. Most important thing is get the chips out.

Yeah, that sounds about like what I want to do. What kind of rpms are you using to get those feed rates?

I didn't think about using compressed air to get the chips cleared.

Thanks!
Brian

I engrave steel and aluminum using a cobalt or carbide mill drill. I have used both 1/4" and 3/16". I initially bought a HSS one and can no longer find those.
I have used RPM's all through the 3000 to 6600 range with good results feeding anywhere from 60 to 150 IPM which I currently use on both metals. DOC is .008". I get fine results just using the simple gdt.shx font. Letter sizes are from .22" to .3".

I do use flood coolant though.

Yeah, that sounds about like what I want to do. What kind of rpms are you using to get those feed rates?

I didn't think about using compressed air to get the chips cleared.

Thanks!
Brian

3000 RPM on a bridgeport, which I had more RPM

You might try an auxillary spindle attached to the head. Check the Tormach website for an accessory to their mill for an example. Wigitmaster has a thread here:
http://www.cnczone.com/forums/forumdisplay.php?f=209 that will give you an idea for the mount and a die grinder to use.

Good luck,
Rick

My DIY high speed spindle, Used parts:
ER 11 1/2" straight shank collet chuck 120mm long, stainless housing, selfmade labyrinth + silicon seal), two high precision angular bearings (nether side) -><-, upper bearing floating type mounted (spring insures preload), then diy star type flexible coupling and then Kontronik Tango 45-13, Upper side of housing is made from aluminum, Tango fixed between six rubber strips for reduce noice and vibration. Then common RC brushless speed control (I use Schulze), 24V comes from AEG Stepping power unit, common current 2...3A when up to 3 mm endmill, 5...8A when up to 7mm endmill and heavy cut cycle. rpm regulated via rc servo tester (6v via step down regulator). Max RPM ca 30.000. Most of all I use 1,6mm two flute carbide endmills for cut parts from 4, 5 and 6 mm 7075 alu plate (full speed!) I have correct cooling system with pump. Carbon fiber plate and glass fiber I gut with "zig-zag" carbide endmills 0.7 ...3,18 mm without any cooling.
I have large enough servo system cnc gantry mill (x-1000mm, y-400mm, Z-200mm, Hiwin rails and, ballscrews) - DIY - most of info I have got from CNC-zone, just readed lot of threads with not any comments or questions from my side (my English is "wooden" , its selfmade as well ;-)
If any interest about my milling stuff - please let me know - will add or send photos and perhaps can help with advices.
Regards,
Herbert Kabi,
khabe@hot.ee
PS:
I have several HF spindles too, included one older very-used KaVo, have rented out to friends - I never use myself anymore - my selfmade spindle is the best.