Needed Collets

[ozzie46]

I needed some collets to work with small dia. stock and can't afford them so I located some plans on the web and adapted them to my mini lathe.

First I needed to turn a #2 and #3 morse taper. I turned the #2 by using my compound and found out that was alot of work turning the compound feed screw
so I made a tailstock taper attachment .

Ron

 

[ozzie46]

With the taper attachment I could use my feed screw to move the carriage instead of using the compound. I wouldn't have had enough travel on the compound for the #3 taper anyway.

I used some old bolts and boy were they hard.

The #2 taper was for the taailstock taper attachment and the #3 was for the beginnings of the collet assembly.

I made a female and a male center for the attachment. These are one time use items so they are not hardened.

 

[ozzie46]

Heres pics of taper turning

 

[ozzie46]

The large #3 taper I made in college back in 82. The Small #2 taper Came with my lathe, I used these to get the settings to turn the tapers.

 

[ozzie46]

Here are the collet asembly pieces.

Colet Taper with Collet Chuk attached

Collet taper and chuck with collet blank inserted. Collet has not yet been dilled to size or slit .

 

[ozzie46]

Collet taper and chuck with collet blank and collet closer nut .

I made three closer nuts before I got it right.

Assmbly in lathe

Assembly extends 2 3/4 in. from spindle.

 

[ozzie46]

Now I'm trying to figure out how the collets should be slit.


1. Should they be slit only part way on three sides or slit full length on one side and part way on two sides?

2.Should they be slit at he front or the rear?

Any help here would be greatly appreciated.


Finally figuered out how to ost pics from photo bucket.

Thanks, Tin Falcon for the advice to use Photo Bucket.

Ron

 

[ozzie46]

Draw bar for Collet assembly

Ron

 

[djc]

Now I'm trying to figure out how the collets should be slit.

Have a look at Taig collets (unhardened), eg

http://www.super-tech.com/root/taig/pix/accessories/tg-1040m.jpg

Also ER-series ones (hardened).

Both are slit alternately from each end.

Holding the buggers to slit them is somewhat of a challenge!

http://unitaig.jalling.dk/index.php?id=99
http://www.neme-s.org/Model_Engineer_Files/3071-Machining Small Collets.pdf
http://www.haythornthwaite.com/Collet Myford.htm

 

[ozzie46]

Thanks djc, thats what I needed.

Ron

 

[Tin Falcon]

Nice work there guys.
tin

 

[ScottM]

yes, very nice work.

For slitting you could turn a mandrel with a shoulder,
superglue the Collet to the mandrel and cut towards the shoulder.
Then heat to break the glue joint and glue if back on the other way to cut the second end.

just an idea...

Scott

 

[Kermit]

Another method I know of would be to use one of the LOW temp alloys that melt around 200 F Use some boiling water and cast yourself a piece to clamp in your mill.

Mcmaster has them and MSC should but I haven't checked them.

Kermit

 

[Cliff]

Hey Ozzie I see your post said that you live in Pueblo, Co. well so do I where do you live at maybe can get together and compair notes. I live across the street from Passkey's on Abriendo. On your collets look in Enco catalog and see how there made and go from there. Cliff.

 

[ozzie46]

Thanks guys,

Cliff, I sent you a PM.


Ron

 

[ozzie46]

I am at a stand still. I cant seem to get a hole thru the collet without run out :wall: :wall: :wall:. I have tried peckdrilling, progressive drilling and running an end mill in for little bit to give the dill bit a straight start. I'm doing it on my chinese 7 x 12 mni lathe. Maybe it just isn't up to it or maybe its ME :shrug: :shrug:.

I am dilling the collets mounted in the collet chuck so they would supposedly be true, but they aren't.


Any and all ideas are welcome.

Ron

 

[Mainer]

Drills wander, the best you can do. To get a concentric hole, you'll need to bore it with a single-point boring bar. Drill, say, 1/16" undersize and bore to final size.

 

[ozzie46]

Drills wander, the best you can do. To get a concentric hole, you'll need to bore it with a single-point boring bar. Drill, say, 1/16" undersize and bore to final size.


Mariner, is there no way to get smaller sizes then? 3/32 and up?

Ron

 

[steamer]

You do the small holes the same way you do the big ones...

Drill rod or drill blanks make nice stock for small boring bars

Even end mills mounted in the tool post make nice boring bars.

For really small holes, you might want to try a pivot drill....it looks like a two flute spade bit. It cuts with less wander because it is stiffer than a twist drill.


Dave

 

[ozzie46]

Thanks for the response guys. What do you think about using small carbide tipped masonry drill bits as small boring bars?


Ron