DIY collet chuck questions

[martik777]

I did something similar on my South bend 9a, by using a 26t stud gear to replace the 20t, I was able to cut 1.5mm with only .06% error. The gear can easily be made on the lathe if you grind your own form tool and slot the teeth (I used PVC, Nylon should work as well). Make an index wheel for your spindle and rig up a pointer: http://www.cgtk.co.uk/metalwork/divider

A few pics of the process: http://s1182.photobucket.com/user/martik777/library/Making gears from PVC or Delrin?sort=9&page=1

Here are a few other combos from a program I wrote (modified for your Logan - please double check the results)

Stud 24 Screw 41 Pos: B3 Error (mm/%) 0.013 / 0.88% Actual:1.48683
Stud 24 Screw 45 Pos: B2 Error (mm/%) 0.005 / 0.35% Actual:1.50519
Stud 24 Screw 51 Pos: B1 Error (mm/%) 0.006 / 0.39% Actual:1.49412
Stud 24 Screw 58 Pos: A8 Error (mm/%) 0.001 / 0.10% Actual:1.50148 *** Did u miss this one?
Stud 24 Screw 62 Pos: A7 Error (mm/%) 0.013 / 0.84% Actual:1.51266
Stud 24 Screw 63 Pos: A7 Error (mm/%) 0.011 / 0.76% Actual:1.48864
Stud 24 Screw 68 Pos: A6 Error (mm/%) 0.006 / 0.39% Actual:1.49412
Stud 24 Screw 70 Pos: A5 Error (mm/%) 0.015 / 0.97% Actual:1.51453
Stud 24 Screw 71 Pos: A5 Error (mm/%) 0.007 / 0.45% Actual:1.49320
Stud 24 Screw 74 Pos: A4 Error (mm/%) 0.002 / 0.15% Actual:1.49779

Stud 20 Screw 48 Pos: A8 Error (mm/%) 0.012 / 0.79% Actual:1.51190
Stud 31 Screw 48 Pos: B4 Error (mm/%) 0.009 / 0.58% Actual:1.49129

If you want combos for other pitches let me know

 

[strantor]

I did something similar on my South bend 9a, by using a 26t stud gear to replace the 20t, I was able to cut 1.5mm with only .06% error. The gear can easily be made on the lathe if you grind your own form tool and slot the teeth (I used PVC, Nylon should work as well). Make an index wheel for your spindle and rig up a pointer: http://www.cgtk.co.uk/metalwork/divider

A few pics of the process: http://s1182.photobucket.com/user/martik777/library/Making gears from PVC or Delrin?sort=9&page=1

Here are a few other combos from a program I wrote (modified for your Logan - please double check the results)

Stud 24 Screw 41 Pos: B3 Error (mm/%) 0.013 / 0.88% Actual:1.48683
Stud 24 Screw 45 Pos: B2 Error (mm/%) 0.005 / 0.35% Actual:1.50519
Stud 24 Screw 51 Pos: B1 Error (mm/%) 0.006 / 0.39% Actual:1.49412
Stud 24 Screw 58 Pos: A8 Error (mm/%) 0.001 / 0.10% Actual:1.50148 *** Did u miss this one?
Stud 24 Screw 62 Pos: A7 Error (mm/%) 0.013 / 0.84% Actual:1.51266
Stud 24 Screw 63 Pos: A7 Error (mm/%) 0.011 / 0.76% Actual:1.48864
Stud 24 Screw 68 Pos: A6 Error (mm/%) 0.006 / 0.39% Actual:1.49412
Stud 24 Screw 70 Pos: A5 Error (mm/%) 0.015 / 0.97% Actual:1.51453
Stud 24 Screw 71 Pos: A5 Error (mm/%) 0.007 / 0.45% Actual:1.49320
Stud 24 Screw 74 Pos: A4 Error (mm/%) 0.002 / 0.15% Actual:1.49779

Stud 20 Screw 48 Pos: A8 Error (mm/%) 0.012 / 0.79% Actual:1.51190
Stud 31 Screw 48 Pos: B4 Error (mm/%) 0.009 / 0.58% Actual:1.49129

If you want combos for other pitches let me know

Yes, I did miss that one. Thank you for pointing it out. A 58T gear will be easier than a 74T gear anyway. I just ordered a ER40 collet nut so I guess this project is a "go."

Is your program that you wrote proprietary? I would be interested in playing around with it if you don't mind sharing. But if not, I understand. I want to make some changes to my spreadsheet so that it generates gear combinations - it seems your program does this and I'd like some inspiration as to how it's done. I'm sure I could figure it out given enough slamming my head against the wall, but short cuts are always nice. Generating gear combos is definitely a few steps above manually entering combinations and seeing if the numbers work out; the past two posts are a perfect example - I missed the better solution because I was manually poking around.

 

[martik777]

PM me your email and I will send it to you.

 

[strantor]

So if anybody else was wondering "can you print lathe change gears on a 3D printer?" The answer, at least for now until this thing flies apart (which I highly doubt it will), is "Hell yeah!"

Following Martik777's discovery, I calculated a new 58t gear and drew it in sketchup, then printed in Nylon645. I didn't optimize my printer and I didn't dry the filament. I printed much much too fast because I'm impatient, and below is the result; a 58 "tooth" gear-like object that cuts 1.5mm thread:






Above you can see the bottom layers lifting up off the print bed as it cools, causing distortion in the tooth profile. This is because I'm not printing on the proper bed material for nylon, I'm printing too fast, my print chamber is not heated (because I don't have a print chamber - open air), etc. This distortion did not have any appreciable effect on the performance of the gear, nor did the fact that the "teeth" in no way resembled anything like an involute gear tooth with a 14.5degree pressure angle or any standard pressure angle - because I was printing about 10X faster than you're supposed to.


And there she is on the lathe. I thought maybe the steel gear would wear the nylon teeth into a more proper looking gear tooth, but no such luck. This Nylon doesn't seem to take a hint from anything. I wasn't even able to file it in places where it needed filing. It just keeps on trucking along with those f*'d up teeth, and does a fine job like that, too.

And finally, my 1.5mm test threads:



I couldn't find my metric thread gauge, nor any 1.5mm bolt of any useful length, but here it is with a little stub left over from when I cut 1.5mm locators for my chinese chuck.

 

[martik777]

Looks great!

How long did it take to print and what model printer was it?

Is that an electric drive on your leadscrew by the tailstock?

 

[David Kirtley]

I couldn't find my metric thread gauge, nor any 1.5mm bolt of any useful length, but here it is with a little stub left over from when I cut 1.5mm locators for my chinese chuck.

Did you make any adjustments on the percentage fill or the number skin layers?

 

[strantor]

Looks great!

How long did it take to print and what model printer was it?

Is that an electric drive on your leadscrew by the tailstock?

It took just over an hour on a reprap prusa .

No electric drive on the lead screw. However that is another project bouncing around in my head. I have an Omron CP1L, which is a PLC trying to cross over into CNC controller territory. I have a box full of high resolution encoders, a 3ph fractional HP motor, and a spare VFD. I think sooner or later I'm disgrace the antiquity of this classic lathe and turn it into an affront to the CNC world. I'm thinking I might call it "ELS_Plus (bastard)." I should be able to turn any pitch I want, and have other functions, like constant surface speed and DRO. All I need is a beefy stepper and stepper drive. And mybe another stepper drive and motor for the cross slide... but I'm getting ahead of myself.

 

[Andre]

*have not read the whole thread per time constraints*

My idea would be to surpass the extraction ring if too hard to machine, and use inserted hardened pins through the side.

 

[strantor]

Did you make any adjustments on the percentage fill or the number skin layers?

You talking about the 3d print? Odd selection to quote

I was heavy into 3D printing about 6 months ago or more, maybe a year ago. I was playing with stronger polymers than the usual ABS and PLA. I was trying to find something viable for printing a prosthetic hand for my dad. I was trying different infills, temps, layers settings, etc for different polymers, and then life happened. I got so buried in work and family that the printer got more and more dust on it.

So to answer your question, yes and no; I used whatever the last settings were that I was playing with, which I believe were for some variant of PET, and not Nylon. I'm actually surprised it worked at all.

 

[David Kirtley]

You talking about the 3d print? Odd selection to quote

That's what I get for not previewing the post. I was going to quote something and lost it. Thought I had deleted all the quote stuff.

Any bad experiences from the other polymers? I have only done abs and a little pla. Not that impressed with abs. It always tried to shrink and curl off the bed with larger prints. Adjusting the bed temp didn't really seem to solve much.