[Spinnetti]

BTW - Your RPM is at least 2X what it should be, or your feedrate is 1/2 what it should be, assuming HSS tooling. If carbide, it's even worse. For cast iron, you should be running 30-50 SFPM, and your chipload should be on the order of 0.002"/tooth for HSS. For carbide, double or triple the SFPM.

Regards,
Ray L.

Thanks Ray, that's what I was looking for. I'm always chicken to crank up the feed. Seems like different software gives me different stuff. Is there a chart somewhere that gives starting SFM for various materials and best cutter type for that material? Seems like a bit of voodoo.

Cheers.

[bruce34rr]

I have also had problems when using End mills, with the TTS holder pulling out of the R8 collet on heavy cuts (770CNC, Carbide 3/8" endmill, 1018 steel) even after I followed the tech note about cleaning/greasing the drawbar etc. I found that if I used my auto Torque wrench and tighened the drawbar to >20 ft-lbs, the pull out stopped. Unfortunately, I then bought a PDB and if I set the preload to anywhere near 20 ft-lbs, the tool would not release when the PDB was operated (@105 psi air). So for heavy cuts I have been tightening manually which defeats the purpose of the PDB but gets the job done. Recently I watched a video on You-Tube (look for "TTS Runout - R8 Collet") about honing the R8 collet to get a better grip on the holder and reduce runout which might help reduce pullout when using less drawbar torque but haven't had a chance to see what the results are.

Bruce

[btu44]

I have also had problems when using End mills, with the TTS holder pulling out of the R8 collet on heavy cuts (770CNC, Carbide 3/8" endmill, 1018 steel) even after I followed the tech note about cleaning/greasing the drawbar etc. I found that if I used my auto Torque wrench and tighened the drawbar to >20 ft-lbs, the pull out stopped. Unfortunately, I then bought a PDB and if I set the preload to anywhere near 20 ft-lbs, the tool would not release when the PDB was operated (@105 psi air). So for heavy cuts I have been tightening manually which defeats the purpose of the PDB but gets the job done. Recently I watched a video on You-Tube (look for "TTS Runout - R8 Collet") about honing the R8 collet to get a better grip on the holder and reduce runout which might help reduce pullout when using less drawbar torque but haven't had a chance to see what the results are.

Bruce

That would be my video and since then I have installed a PDB.
For any who are interested, this is my experience.

Using a Cleveland 1/2", 3 flute, powdered metal aluminum rougher in a set screw holder for contouring 6061:

Pre PDB:
RPM 3200, feed 55, radial .17 (30%), depth .35 = MMR 3.27, .9 HP

Post PDB:
RPM 3200, feed 40, radial .17 (30%), depth .3 = MMR 2.04, .56 HP

So the PDB caused a pretty good hit to the MMR. I have preloaded my bellevilles to the limit of the holder just releasing. I also experience pull out at any level of chatter. Pre PDB I could get away with a little.

I'm thinking about trying these:

McMaster-Carr

The're dimensionally the same. They have a working load of 1890 lbs and a flat load of 2698 lbs. This seems to be correct for a R-8 drawbar tension. (Based on a Google search but nothing official)
They come in high carbon steel and 17-7 PH stainless at double the price.

Any opinions of which material would be better?

Has anyone who has purchased Tormach replacement bellivelles...what was the cost?

Thanks,
Barry

[tbaker2500]

Thanks Ray, that's what I was looking for. I'm always chicken to crank up the feed. Seems like different software gives me different stuff. Is there a chart somewhere that gives starting SFM for various materials and best cutter type for that material? Seems like a bit of voodoo.

Cheers.

I highly recommend G-Wizard. It has saved me more than it's cost in broken bits. It got me through to voodoo phase to where I can have a good guess myself on proper feeds.

[Spinnetti]

I highly recommend G-Wizard. It has saved me more than it's cost in broken bits. It got me through to voodoo phase to where I can have a good guess myself on proper feeds.

Yeah, good idea, but loathe "renting" software. Great for the developer, lousy for the customer. I'd rather pay for a new version if upgrades are worth it to me, otherwise, I'd be happy to keep an old version. Time to dig up the machinists handbook sounds like!

I also used brake cleaner on the collet and TTS holder, and tightend the drawbar so it just releases, but still won't handle much of a cut seems like. Right now I'm sitting at 850rpm and 5.5 ipm but haven't fine tuned. Issue is that this is just too slow - 1hr per part which "won't cut it" so to speak. I assume Carbide would let me crank it up? Any recommendations for the best reasonably priced tooling to to cut iron? (brake rotors)...... . Right now I'm doing (2x) .4 DOC and (4x) .050 Axial DOC 16 times which makes for some loooong cycle times.

[DiverBob]

Yeah, good idea, but loathe "renting" software. Great for the developer, lousy for the customer. I'd rather pay for a new version if upgrades are worth it to me, otherwise, I'd be happy to keep an old version. Time to dig up the machinists handbook sounds like!

I believe that once you purchase the software, if you do not renew the license then the software just downgrades to become a 'lite' version. The only limit i know is you are lomited to 1 HP for all the calculations. Since the 770 is a 1 HP motor, my one year subscription continues to be good for me. Check the website to verify my 'facts', I've been known to be wrong occasionally!

Bob S.

[Spinnetti]

I believe that once you purchase the software, if you do not renew the license then the software just downgrades to become a 'lite' version. The only limit i know is you are lomited to 1 HP for all the calculations. Since the 770 is a 1 HP motor, my one year subscription continues to be good for me. Check the website to verify my 'facts', I've been known to be wrong occasionally!

Bob S.

Good call Bob.. I'll check that. I have an 1100, but still, that softens the blow somewhat. What would be really handy is for it to recommend tooling diameter, depth of cut and axial engagement - it would save a lot of "what ifs" messing with tooling diameter.

I also found "ME Consultant" which is much cleaner on the UI and seems pretty good. I also see there are iphone apps which I'll check out shortly.

[MichaelHenry]

Good call Bob.. I'll check that. I have an 1100, but still, that softens the blow somewhat. What would be really handy is for it to recommend tooling diameter, depth of cut and axial engagement - it would save a lot of "what ifs" messing with tooling diameter.

I also found "ME Consultant" which is much cleaner on the UI and seems pretty good. I also see there are iphone apps which I'll check out shortly.

The Lite version of G-Wizard gives you 1 HP for every year of the retail license you "lease". I bought the 3-year "lease" so will get 3 HP in my Lite version when the lease expires in a year or so. The author claims that you will still receive upgrades and forum-based tech support on the Lite version.

I also have ME Pro and actually like the simpler interface more and appreciate the printable specs for thread forms but G-Wizard has a better selection of materials.

G-Wizard is being offered with some sort of discount for > $100 at present and a 3-year license might qualify for that discount. It's worth checking out if you are on the fence.

Mike

[Spinnetti]

The Lite version of G-Wizard gives you 1 HP for every year of the retail license you "lease". I bought the 3-year "lease" so will get 3 HP in my Lite version when the lease expires in a year or so. The author claims that you will still receive upgrades and forum-based tech support on the Lite version.

I also have ME Pro and actually like the simpler interface more and appreciate the printable specs for thread forms but G-Wizard has a better selection of materials.

G-Wizard is being offered with some sort of discount for > $100 at present and a 3-year license might qualify for that discount. It's worth checking out if you are on the fence.

Mike

Thanks Mike. I'm on the fence between ME pro and Gwhiz. ME pro outputs correlate well to tooling mfgs. recommendations and uses pretty conservative recommendaions suitable for our smaller machines. Materials in ME are fine for me, and the app doesn't look so thrown together, but I appreciate the support Bob gives and participation in the formums.. might end up getting both and comparing results with my real world findings, then sticking with the better of the two long term.

[dbrija]

Thanks Ray, that's what I was looking for. I'm always chicken to crank up the feed. Seems like different software gives me different stuff. Is there a chart somewhere that gives starting SFM for various materials and best cutter type for that material? Seems like a bit of voodoo.

Cheers.

GWizard says 800RPM, 5-6IPM for your cut.