Mini Lathe ER Collet Chuck

[cfellows]

Yet another improvement for my mini lathe.  I have a number of ER20 collets and decided a collet chuck for my mini lathe would be nice.  I would have preferred an ER32, but ER20 was what I had.

I started with a 3" diameter piece of 12L14. 



I used my Logan 12" lathe so I could remove the metal faster.  I left the nose about .050" oversize so I could finish it in place on my minilathe.



Next I parted off the piece turned it around and chucked it by the nose so I could cut the recess in the back.  Then I drilled and tapped the mounting holes 1/4-28.  I used my rotary table to locate and drill the holes.





Next I mounted the blank on the mini lathe so I could cut the threads.  I had never used the min lathe to cut threads, so had to go through some setup and make some bushings to hold the banjo.  Here is the change gear set up.  I was able to approximate the 1.5mm thread pitch by using a 60 tooth gear on the lead screw and a 57 tooth as the driving gear.  These two gears just happened to be in the gears included with the lathe and gave me a ratio of .945 : 1 with a 16 tooth per inch lead screw.



Here's the threaded nose piece.



I bored a half inch hole through the center of the chuck, then set up the compound to cut an 8 degree tape in the nose piece.  Here is the lash up I used to set the angle...



And here I'm ready to start boring...



Here's the finished taper bored...



And here's the finished chuck with a 1/2" rod chucked in it.



I made the nose a little longer than need be, but it turns out I can't get the carriage any closer to the head stock so it turned out good.  I also want to replace the hex head bolts with button head socket head screws... should be a little less dangerous.

Chuck

[Don1966]

Nice job Chuck. Good to see you back, it seems you disappeared on us for a while.

Don

[cfellows]

Thanks, Don.  Unfortunately, I've got half a dozen or more different projects underway.  I'm working on two, 3D printers, the vertical single IC engine, an arduino project to add a stepper motor and encoder to my mini-lathe, the Bessemer horizontal oil field engine, and, oh yeah, the occasional tool mod like this collet chuck.  I've also become involved with the Tormach CNC mill at the Techshop and I've begun working on converting my own Mill/Drill to CNC.

Not enough hours in the day...

Chuck

[Mosey]

I trust you are aware of an APP for your smartphone called SetSquare, that is a digital protractor that easily indicates tenths of a degree. It might be useful for setting those internal angular bores. It is free. Mosey

[gerritv]

I couldn't find that app for Android so used Protractor and Leveler instead.

[DICKEYBIRD]

I trust you are aware of an APP for your smartphone called SetSquare, that is a digital protractor that easily indicates tenths of a degree.

Being a Luddite, I'm having trouble visualizing how one would use a phone to setup an accurate taper on a real machine in the real world.  I know they have accurate accelerometers, inclination sensors, yada, yada but c'mon, really?

The only way I could use my ancient phone to help would be to call somebody that had the tools & knowledge to come do the setup for me!

[cfellows]

In the past I've used my mitre saw to cut a wedge of 1/2" plywood to the angle I need.  That usually has an accuracy of half a degree or better.  Start with a 3 or 4 inch wide piece of plywood or Masonite long enough to comfortably hold in the saw.  First make a 90 degree cut on the end.  Then move it over an inch or whatever distance you need and set the blade to the angle compliment.  For example, if you need an 8 degree angle, set the blade to 82 degrees.  That will give you an 8 degree wedge of whatever width you want.

I've often used this method to cut a thin wedge to support work at the proper angle in my milling vice.  As I said, not as accurate as a sine bar, but still probably within a degree or less.

Chuck

[Mosey]

I trust you are aware of an APP for your smartphone called SetSquare, that is a digital protractor that easily indicates tenths of a degree.

Being a Luddite, I'm having trouble visualizing how one would use a phone to setup an accurate taper on a real machine in the real world.  I know they have accurate accelerometers, inclination sensors, yada, yada but c'mon, really?

The only way I could use my ancient phone to help would be to call somebody that had the tools & knowledge to come do the setup for me!

Granted, it's a little fiddly, as the phones are slippery and tend to move out of position, but it can be done quite nicely. You just lay your phone on top of the toolpost ,zero it, and swivel the post to the desired angle. Would I like a real digital protractor? Does the bear s..t in the woods? Yes! I've actually done this satisfactorily. Cost is zero.
Mosey

[DICKEYBIRD]

Thanks, I didn't realize they could somehow measure angle changes to that level of accuracy lying flat on their back.  I learn sumthin' new every day.

[Mosey]

Well, you're right of course, this is at best a home-play level of precision, but for guys who don't spend, it is workable. Maybe some sticky tape on the tool-post would keep it steady.
Mosey

[cfellows]

Mosey, are you having us on here?  I can't find a SetSquare app anywhere on google.

Chuck

[gerritv]

I trust you are aware of an APP for your smartphone called SetSquare, that is a digital protractor that easily indicates tenths of a degree.

Being a Luddite, I'm having trouble visualizing how one would use a phone to setup an accurate taper on a real machine in the real world.  I know they have accurate accelerometers, inclination sensors, yada, yada but c'mon, really?

The only way I could use my ancient phone to help would be to call somebody that had the tools & knowledge to come do the setup for me!

the phones now have  a very accurate compass and an inclinometer inside. The compass is being used as a protractor in these small apps.

For Android I tried a few and ended up with https://play.google.com/store/apps/details?id=air.Protractor.Leveler:

[cfellows]

Sorry, Mosey, I just found it.  It's called iSetSquare.

Chuck

[Mosey]

Now you're really going to be dangerous! Hope it helps you with those millions of projects you are cranking out. Glad to help.
Mosey