Turning small parts...

Turning small parts...

Joined: August 20th, 2006, 5:36 am

March 3rd, 2012, 5:01 pm #1

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
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Joined: July 25th, 2011, 2:18 pm

March 3rd, 2012, 5:14 pm #2

You can make up a split sleeve & then chuck on to the sleeve.
Jig grinedrs use collets in standard inch sizes & are very precision & pretty small.
Use a drill bushing but you would have to put a split in it for it to compress.
Just 3 options, hope this helps

Mike
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Joined: June 7th, 2010, 12:14 am

March 3rd, 2012, 7:06 pm #3

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
Drill through for a snug fit on your stock.
Mark the piece with respect to your chuck jaws so you can put it back in after removing. Marking pen is fine.

Remove your "collet" and slit one side into the hole. A fine blade hack saw or a jeweler's saw.

Viola! A useful "split chuck"

I've wrapped small stock with copper or iron wire to build it out as well.



Easier for some might be to pick up a collet for a Dremel tool. Or hold a drill chuck in your lathe chuck.

Last edited by CalG on March 3rd, 2012, 7:08 pm, edited 1 time in total.
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Joined: August 23rd, 2002, 4:50 pm

March 4th, 2012, 1:54 am #4

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
I have to imagine that with 1/8in stock you're not doing much to generate cutting pressure. I've gotten away with clamping small stock in a drill chuck and then clamping on the OD of the drill chuck with the lathe chuck. Quick. And. Dirty. But it works.

I also made myself an adapter that clamps in the lathe chuck but accepts R8 milling collets. Again, not ideal, but versus buying the adapter, collets, and drawbar for a 5C system I think it's worth it.

-Chad
Last edited by Airgunner4life on March 4th, 2012, 2:03 am, edited 1 time in total.
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Joined: May 8th, 2001, 4:06 pm

March 4th, 2012, 2:09 am #5

just a thought
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Joined: January 1st, 2012, 11:50 pm

March 4th, 2012, 3:11 am #6

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
I have a proper headstock chuck but usually just leave my 3 jaw chuck in place and use one of these:

http://www.sears.com/shc/s/p_10153_1260 ... 118710301P
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Joined: June 16th, 2009, 7:43 pm

March 4th, 2012, 5:23 pm #7

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
Get yourself a 5C closer and be done with it. The semi-cheapo closer I got from CDCO is more than adequate. I make use of soft collets in many applications.

"Silence is the only thing that can hinder the Truth"
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Joined: August 20th, 2006, 5:36 am

March 4th, 2012, 7:57 pm #8

As I understand the terminology, a closer has a lever on the outside of the head stock that pulls the collet closed. A chuck, on the other hand, uses a scroll and key just like any other chuck. I've looked seriously at a collet chuck, both at CDCO and elsewhere. Big difference in prices!

I'm currently leaning heavily towards a set of 5C collets and a couple of collet blocks for now. That would give me some options for both the lathe and mill, and I'd already have the collets when I can afford to buy a chuck.

I'm also considering one of the quick change sets with a Morse taper adapter, I think they're ER series collets. My concern there is run-out stacking up, the biggest Morse taper available is a 3, my spindle is an MT-5, so I'd have to use my adapter. Seems like it's just asking for concentricity issues. And of course, I'd have to make a draw bar, but that's not a big deal.

Re: CDCO, seems to be a pretty hit or miss outfit. Lowest of the low in Chinese import tooling, and a hit or miss rep for CS, too. What's your experience been like?

To the rest of you that responded, thank you, there's some good ideas here, and I'll very likely try most if not all . Later.

Dave
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Joined: March 6th, 2002, 3:54 am

March 5th, 2012, 1:22 am #9

I have an older 12x24 Grizzly lathe, it's ended up being a really good machine for what I do, but I've recently discovered a flaw. I'm currently playing around with a QB HPA conversion, and needed to turn some new valve parts. Problem is, my chuck won't hold anything under about 1/4" diameter, but I'm working with 1/8" O1 tool steel for valve stems. I've actually resorted to using my mill as a vertical lathe, stick the stock in a collet and clamp a lathe tool in the vise. It works, sort of, but it's a lot of by guess and by god . And it makes a simple little valve stem and head more work than turning a new valve body would be.

So how do you guys handle small stuff? Am I going to have to invest in a collet chuck, or is there a less expensive alternative? Thanks.

Dave
Even doing CNC lathe work, we make bushings to hold odd sized pieces, or when doing second opps on parts that we don't want to mess up the threads.

Making a bushing is quick and easy. The guys giving this tip are right on the money. You can split only one side but it will usually run even more true when splitting both sides. I cut a little OD groove for an O-Ring which acts as a rubber band to keep both halves together after it's been split or cut into two pieces.

I like to make the bushing a step bushing. Start with something like 1" OD, Face material, and drill your hole. turn one OD down to .625" for a length of say 1", cut a groove for an O-ring, then part it off for an overall length of 1.25" Now saw one side or both sides. Slip your O-Ring on, and your small material inside. Now the step will let you align it straight with the jaws in chucking on the .625 with the 1" facing the jaws.

Personally, a 5C collet system is an investment that I would recommend making if you have the money. They are very nice and handy.



Shoot Safe,

Bryan
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Joined: June 16th, 2009, 7:43 pm

March 5th, 2012, 3:25 pm #10

As I understand the terminology, a closer has a lever on the outside of the head stock that pulls the collet closed. A chuck, on the other hand, uses a scroll and key just like any other chuck. I've looked seriously at a collet chuck, both at CDCO and elsewhere. Big difference in prices!

I'm currently leaning heavily towards a set of 5C collets and a couple of collet blocks for now. That would give me some options for both the lathe and mill, and I'd already have the collets when I can afford to buy a chuck.

I'm also considering one of the quick change sets with a Morse taper adapter, I think they're ER series collets. My concern there is run-out stacking up, the biggest Morse taper available is a 3, my spindle is an MT-5, so I'd have to use my adapter. Seems like it's just asking for concentricity issues. And of course, I'd have to make a draw bar, but that's not a big deal.

Re: CDCO, seems to be a pretty hit or miss outfit. Lowest of the low in Chinese import tooling, and a hit or miss rep for CS, too. What's your experience been like?

To the rest of you that responded, thank you, there's some good ideas here, and I'll very likely try most if not all . Later.

Dave
If you're able to machine the mounting plate accurately, I believe you'll be able to get the same results as I have which is .0007 max run out 1" from the collet face. I bought one brand new Hardinge %C collet to try and eliminate variables in checking my mounting of the chuck. I am able to maintain those tolerances even with my other imported collets. When doing really close work that requires near perfect concentricity, I bore a soft collet. I goofed around with all the work-arounds and I have decided my time is worth the investment.

"Silence is the only thing that can hinder the Truth"
Last edited by jlucas50 on March 5th, 2012, 3:27 pm, edited 1 time in total.
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