Chris G0704 Build

I ran a test cut using a Best Carbide 3/8" 3F Carbide at 6750rpm, 81IPM (.004" IPT) .75" DOC and .030" WOC (1.5" MRR) and worked my way up to .060" WOC (3.65" MRR) in .005" increments. The machine seemed quite happy at 3.65" MRR. I stand corrected. Apparently my weak spindle motor and sloppy gibbs were giving me the impression that the machine was tearing itself apart.
 
GunsOfNavarone said:
I gotta ask as I am ready to do something now...
What does it cost to do this kind of conversion? The little I have checked into makes me want to buy a Tormach or..... instead of converting what I have. I assume the ballscrews have completely eliminated the backlash? There is the learning curve as well. I'm jealous! Great work! I really think something like this is more than I want to bite off. The VFD conversion wan't bad on my lathe, but this is FAR more entailed.
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I don't remember what I paid to be honest. The mounts and ball screws were around $1k. Automation Technologies has a conversion kit now. I bought my drives, PS, steppers, etc from them too. The motor and VFD I just bought were $400.

If I had to guess it'd be around $2k-$2.5k to get one up and running. Oh yeah add in a PC, and software (mach4, Acorn, linuxNC). Add another $400 for the bigger motor. The belt drive you can do for about $100. Maybe $3k to get up and running with a decent machine base. Then you need a bunch of tool holders. I use R8 set screw holders and I have about 20 at the moment. Then plan on ruining a few hundred dollars worth crashing them, burning them up, etc.

You need to ask yourself do you want a machine to make money with or just a machine to play with and upgrade as you go? I have countless hours into my machine. I originally bought mine to make money with. I do enjoy upgrading it from time to time it but most of the time I just want it to work. Even a Tormach isn't going to give you industrial class reliability though. If I had the room I'd buy an old Fadal or VF1 and just make parts.
 
A quick update: Since installing the 2hp motor I've been able to double the MRR on every one of my programs that I've run in aluminum to roughly 3" pre minute. I've done this mostly by increasing the WOC. I feel really comfortable with the machine running 81IPM (.004 IPT) with a 3 flute carbide end mill. The other day I was tweaking a program and had the feed override set to 150%. The mill powered right along at 120IPM and 4.5" MRR but the finish suffered a bit.
 
I got the flat parts of the new motor mount machined out of 1/2" 6061 last night. The inner pieces mount to the head and the outer pieces mount to the motor.

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I went to make the round threaded spacers I need and realized that my 3/8-16 tap can't cut deep enough. :rolleyes:
 
I was thinking a pulley tap would work, but that nut tap looks like what I need. I'll have to see what the local tool shop has in stock.
 
ChrisAttebery said:
I was thinking a pulley tap would work, but that nut tap looks like what I need. I'll have to see what the local tool shop has in stock.
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I pulley tap has a long reach, but the overall shank diameter is larger than the tap part


top - a 3/8”-16 pulley tap
Bottom - a 3/8”-16 nut tap


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