[Cold Fusion]

That is exactly what I need! I do a lot of cutting with 1/8 endmills, and 3200rpm is killing my job time.

Yep, I generated all that in Onecnc. It has a nice gear wizard in the shapes menu. All you need to know is the pitch diameter, tooth count, and pressure angle.

[rustyolddo]

Here's the link, it's simple enough to do. I would caution against using the $15 Harbor Freight grinders, the runout is horid. Possibly a Foredom handpiece or if you want to go air, get a Dotco die grinder. You could also build a mount to clamp a small trim router to the spindle of the mill.

http://www.homemetalshopclub.org/new...eb04.html#mill

[Cold Fusion]

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

Any idea what sort of runout that would have? Instead of doing it the way the website did it, I'm going to mill a quill mounted bracket that extends to the side to hold the grinder.

[rustyolddo]

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

Any idea what sort of runout that would have? Instead of doing it the way the website did it, I'm going to mill a quill mounted bracket that extends to the side to hold the grinder.

Those are the pits, same chicom ones that Harbor Freight sells for $15. You'll spend more money on busted end mills. Dotco's show up on ebay from time to time. If you are going to use a side mount, look at a Foredom, quieter and you don't have a compressor running constantly to keep up. More power and variable speed. There is also a guy selling Proxxon router motors on ebay, they have a 1/4" collet. Be a little larger but you could still side mount. A laminate trimmer or a Rotozip is another consideration.

[Cold Fusion]

What about something like a high speed air powered dentist drill?

[rustyolddo]

What about something like a high speed air powered dentist drill?

That would work or anything from the jewelry industry. You just have to keep in mind that these small devices lack power. More $$ with get you more power. You know, you might even find some R/C motors that would serve the purpose but you'd have to fab the spindle. You might be able to find one of the cheap air grinders to work but you'd have to go to a Harbor Freight store and pick thru a stack till you found one that was machined well. You could buy a Foredom handpiece and modify any kind of motor to fit on it air or electic. #30 handpieces run about $40 new on Ebay. Lots of ways to get the job done. The critical issue is very little runout. When you are running tiny tools, a small amount of runout will kill the tool quickly. Small endmills are expensive too. You'll need enough power to keep it from stalling esp. in aluminum.

[Cold Fusion]

Power has me concerned. About 90% of it's use will be slotting with 1/8 endmills. The rest will be odd jobs with 1/32-1/16 endmills. I'm afraid that with an air powered spindle, I won't have enough power to really go through the aluminum quickly. Fabbing the spine myself is possible, although hard because I don't have access to a lathe.

[rustyolddo]

What I'd recommend at this point is a Foredom or Grobet flexshaft machine. THe hand pieces are uniform in shape so it's easy to fab a mount, they are designed to have very little runout, made for running tiny little burrs & drills, motors are made to handle the varible speeds & speed control, and have lots of power.

The #30 hand piece is just a regular drill chuck. THere are some handpieces that use collets and some are even quick change. You could use an optical tach ($40 on ebay) to set the speed with and you'd be right on for the OneCNC speed & feed settings.

THat would be the route I'd go, the next step up would be a router motor of some kind.

[Cold Fusion]

Just finished cutting these for a friend. They are custom Emaxx shock towers made out of 5/16 Delrin. I love this material, because it allows VERY fast cutting and is quite stiff.

[rustyolddo]

Nice! I like Delrin too, great stuff to machine, threads nice, finishes nice. Makes one heck of a mess though. You can often buy "Drops" on ebay. I've got a lifetime supply of 1"x~2" that I bought.

[Builder4wd]

Very nice parts, Cold Fusion. How did you hold down those delrin shock towers when cutting? Could you shed some light on the process behind those parts - how you set up and machined the shock towers and the gears? Did you cut them with multiple setups?

Thanks!

[Cold Fusion]

The towers were easy. I simply left .01 tabs in a few places on the outer profile to hold it in place while taking the through-pass. It was easy enough to trim with a razor blade, and now you can't even tell where I put them.

The gears were a challenge.The aluminum one was cut out of 1/2" 6061. I used a circular pocket to form the hub. I then roughed out the teeth with an 1/8 cutter, leaving .005" on the bottom to keep it all in place. I then used a 1/32" Endmill to cut the actual teeth, again leaving .005 on the bottom. Then I flipped the entire sheet over and cut .006 deep to release the finished gear. I did the Delrin one the same way, minus the hub.

I hope that all made sense.

[Cold Fusion]

Why oh why does Mfgquote.com have to charge $5000 for a membership? It's impossible to find decent quantity jobs anywhere else, because they put all the other sites out of business. How does everyone else do it?

*Goes back to the never ending search for more jobs*

[rustyolddo]

Why oh why does Mfgquote.com have to charge $5000 for a membership? It's impossible to find decent quantity jobs anywhere else, because they put all the other sites out of business. How does everyone else do it?

*Goes back to the never ending search for more jobs*

All you need is your own website and have it set up right in the search engines. Specializing in small one-of runs is a niche market. Have a banner ad put on every R/C web site. Surely there is some R/C enthusiest that will trade custom parts for web design. BTW the Mfgquote issue is being discussed in another thread.

[Cold Fusion]

I haven't taken any pictures of the control system yet, sorry! This is due to me being half incredibly busy, and half lazy. I'll take some soon, I promise

It's been working for a little while now, so I've had a chance to tweak things here and there and generally get a feel for the machine. The mill seems to be performing great, and has yet to fail me in tolerances. The tightest job I've done was a 3.46" bore in cast iron for a motor mount. It had to be within .0005 to work properly. Even I didn't think it would work, but I had nothing to lose by trying. After it was all said and done, the piece worked perfectly...


Now all I have to do is find some jobs to do. Seems like that is the hardest part of this whole business

[Cold Fusion]

Another custom chassis.

[Cold Fusion]

Jig for custom knife handles.

[damae]

Hey CF,

Great looking parts! I've followed your thread for a long time now and enjoy seeing what you make with the finished machine. Keep up the posts -- and if you get time, I'd also like to see photos of your control system. =)

-D

[Cold Fusion]

What if I'm ashamed to show my hobbled together control system? :idea:

Thanks for the compliment! Onecnc made the perfect toolpath, the Bridgeport cut it, and Mach2 controlled everything perfectly. I don't know if I actually did much at all

[Jamf2]

Ashamed of rebuikding a cnc and making it work. Dude great job. I appreaciate your link and I am using it as a guide for my own rebuild.

Thanks and keep it up.