Compact 5 change gears

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fourjc
Posts: 147
Joined: Wed Sep 26, 2007 7:37 pm
Location: MTL

Re: Compact 5 change gears

Post by fourjc »

OMG, I spent 3 days since my return working on a spreadsheet to calculate ratios of gears and trying to get the correct travel per turn of spindle for a given TPI. Got absolutely nowhere because I was using 10 pitch for the leadscrew. I now know how to spell STUPID. Thanks jcfx for knocking me back to reality.
I did not realize that I would need to print 3 60 teeth gears, I guess there is no way around this.
I was going to attach the Excel file but I see it's not accepted. Thanks again for your support.
jcfx
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Re: Compact 5 change gears

Post by jcfx »

The dreaded CRS is usually the worst after a long vacation ;)
Glad you got it sorted out !
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

Took some time getting to this point. The gears are finally in and properly aligned. My homemade gearbox had to be cut back .250” for proper alignment. Lucky my design was easily modified. I printed enough gears to cut 20TPI for the first test tomorrow. The gearbox can engage the leadscrew in 6 different positions so the only way I know how to prevent cross threading is to stop, back off and reverse, that sucks. I’m trying to think of a way to overcome this. Any suggestions.
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pete
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Re: Compact 5 change gears

Post by pete »

Since the compact 5 has no half nut and threading dial your stuck with keeping everything engaged and reversing the motor. Frankly for the little extra it would have cost for Emco to design it into the lathe and make it a lot better machine it's surprising a company like them would do so. Anything I ever thought of for mine without building a half nut assembly and threading dial involved more time than simply reversing the motor.
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fourjc
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Location: MTL

Re: Compact 5 change gears

Post by fourjc »

Thanks pete, I am going to try installing a temp switch that will cut power to the DC motor, the switch will be activated by a prop bar on the carriage. Hopefully the over travel will be constant at a given speed. The thread I have done so far with manual shut off make me feel fairly confident that it will work. I will post the results next week after the electrical modification.
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threAD 20 TPI.jpg
Paddle.jpg
Front control.jpg
pete
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Re: Compact 5 change gears

Post by pete »

I've mentioned it here before a long time ago fourjc and it's too long to repeat the whole story. Burning out the original Emco single phase motor and paying to replace it when you could still get them from Emco was a costly lesson in using the correct lubrication on the power feed assembly. The way the power feed is arranged you can't ever tell there's any drag being caused by it while not using it. And it's motor location makes it easy to forget a check once in awhile with your hand no matter what motor type your using. Just a reminder for you.

While I still have my C5 I've moved to bigger equipment. But after tuning it that little lathe it's still the most accurate machine I've had my hands on and it sure taught me the most about wringing the best accuracy out of a machine. Adding what Emco called leveling plates in there catalog shortly after buying it and then mounting the lathe to a 12.5" x 27" x 1" thick mild steel plate was the best two things I ever did to mine. I have the materials to at least add the same idea as those leveling plates to my much larger lathe. I added a second leadscrew nut to the other end of the carriage and think it's helped keep it from flexing the carriage under heavier cuts. The surface finishes did improve a bit after adding it anyway. Given you were a toolmaker you might possibly consider carving out a whole new carriage out of proper cast iron instead of there ridiculous use of die cast aluminum. Half nuts and a threading dial would then be an easy addition. We both obviously know the machine was designed and built as a very light duty machine. Under certain cutting conditions I've seen fairly serious harmonic vibrations showing up on the surface finishes on longer parts. Even at 2" in diameter. I highly suspect that die cast aluminum tailstock is a big part of it. On my list but not done yet is trying an epoxy granite mix inside the tailstocks hollow areas.

Hmm, I just took a closer look at your latest pictures. That's no stock C5 :-) Seperate feed rod and a carriage mounted FNR switch? If so I'm very impressed.
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fourjc
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Location: MTL

Re: Compact 5 change gears

Post by fourjc »

Threading is successful, my limit switch is great the carriage stops within .005" every cut. I cut 1/4-20 thread in stainless with no problem. I am posting a link to my "onedrive" there is 3 small videos of the stopping mechanism. https://1drv.ms/f/s!Av7bHPiazEVKrloiDGH3dZ2gOqtz
I hope this is legal on this site, sorry if it is not.
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