Tips For Diy Collet Chuck

boostin53

boostin53

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I just received a handful of ER40 collets and a collet nut. My plan is to build a collet chuck for my lathe. What kind of tips do you guys have for me to help me build my chuck?

Also, I don't have any good steel in a diamter large enough for the chuck. But I do have a hunk of 6061 aluminum. Would that be acceptable for a chuck that gets light usage? Or should I get some steel? I know, I knkw, stupid questions. But I'm still in the early stages of learning, very early. I dont get much time anymore with my new job to get time on my lathe.
 
Caution: if your collet holder screws onto your spindle you'll have to make some sort of device/mechanism to keep it from unscrewing if you reverse the spindle. I made mine from 4140, but aluminum would work until the threads (under the nut) wore out.
 
It is a threaded spindle, didn't think about the reversing aspect of it. I however rarely use the lathe in reverse, for the time being. I mostly want to build this collet chuck for my swage die and punch building.
 
First the aluminum won't be a good choice for a collet chuck. And that wasn't a stupid question. Now on with it. What mount does your lathe spindle have. Threaded or something else? That will help as to where to start.
 
1 go on steel. Aluminium could have durability issues on the treaded part and some wear on 8 degrees taper.

2 Mark the position you put it on the lathe and keep this position forever. (If you use flange spindle)

3 Do a soft (less prone to grab things) knurl on the biggest diameter. You need to manually rotate de spindle everytime.
 
boostin53 said:
I just received a handful of ER40 collets and a collet nut. My plan is to build a collet chuck for my lathe. What kind of tips do you guys have for me to help me build my chuck?

Also, I don't have any good steel in a diamter large enough for the chuck. But I do have a hunk of 6061 aluminum. Would that be acceptable for a chuck that gets light usage? Or should I get some steel? I know, I knkw, stupid questions. But I'm still in the early stages of learning, very early. I dont get much time anymore with my new job to get time on my lathe.
Click to expand...

Let's make this clear. There is no such thing as a stupid question. One of the purposes of this forum is to help those that have questions on how to accomplish a task. And this doesn't apply to newbie's only. I've been involved in machining for 45 years and I still am learning and asking for guidance. OK, I'm done preaching.

To answer your question I would not recommend using aluminum. Because aluminum is soft and the collets are hardened you will get brineling of the aluminum each time you tighten the collet nut. This brineling will ultimately lead to runout that will become worse over time. I recommend using steel for your chuck. There are numerous grades of steel that will work but I would keep it simple and use low carbon steel. Your cost will be minimal.

Hope this helps.

Tom S.
 
Okay, cool. This is exactly the advise I was looking for. The spindle is a threaded spindle, a 1 1/2"x8tpi. Which is kind of neat because I have only three I inside threading operations under my belt. And the last one was the same dimensions for a project for my work. That's also where I have the hink of aluminum from.

So on to steels, what would be a good steel to use? I don't currently have any steel over 1.5", so I would have to buy something.
 
Mild steel will work I used A1 tool steel because I had it laying around. When I made mine I bored and threaded it for the spindle, then mounted it on the spindle for the rest of the machining. That way it is true to the spindle.
 
kd4gij said:
Mild steel will work I used A1 tool steel because I had it laying around. When I made mine I bored and threaded it for the spindle, then mounted it on the spindle for the rest of the machining. That way it is true to the spindle.
Click to expand...

That was my plan. Thread it for my spindle then finish the rest of the chuck while mounted directly to the spindle. On to looking for a well priced hunk of steel...
 
Hey boostin,

Another idea I saw here recently......make the body of the chuck from square or hex steel. The advantage is that the chuck and collets can perform double duty by holding things while clamped in your mill vise for milling square or hex external features.

I will try to find a link to the one I saw here. It was hex and I thought it was very clever.

EDIT: here is the link:
http://www.hobby-machinist.com/threads/er25-collet-chuck-for-atlas-618.41636/
It was made by user mattthemuppet.
Credit where it is due!

-brino
 
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