chuck jaw alignment question

[Vern Smith]

I've never owned an air chuck before so I have no basis of comparison. The GT-10 comes with a Samchully power chuck. I set mine up a day or two ago and immediately noticed that the jaws do not sit square on the round stock. The back of the jaw contacts the stock but the front of the jaw never makes contact. You can see light under the front 50% on the jaw. I've attached a poor photo. The air gage (it's an pneumatic draw tube system) goes to 80 lbs during the clamping and unclamping sequence which is only 5 lbs. under the line pressure.

The machine comes with rigid tapping. Have any of you used rigid tapping on your Haas lathes? Any tips?

One thing I see already, 6061 makes some of the biggest ugliest birds nests I've ever seen. I'm using inserts recommended for aluminum with chip breakers but they don't break the chip at all, just curl it a little tighter then my manual does

[wms]

Vern,

Those look like soft jaws..correct??

If so, those would have to be "Bored" before you use them..

As for the birds nest...more feed..or less speed with same feed..or could be more depth of cut..some thing to get the chips to break..check the vender for a chip load..my bet is you are under it..

[HelicopterJohn]

Hi Vern,

Here are a couple of threads you might want to look at.

HAAS SL20 Problem

How to true my lathe chuck?

John

[Vern Smith]

That could be the problem. The jaws are steel but a file makes a mark with little trouble, 15 minutes with the chuck maker's manual found an oblique reference to "standard soft jaws". Geeze, I don't know s*it about lathes. I thought all "soft" jaws were aluminum.

I'll try the speed, feed changes for the chip situation. I've been using 4000 RPM and .002 to .003 IPT with a .04 to .06 depth of cut. Now that I think about it the "diameter" concept that's new to me may mean my DOC is really .02 to .03. Well, back to the drawing boards

Vern

J C, thanks for the links.

[Matt@RFR]

Vern, I've run tiny Atlas lathes harder than that!

[HelicopterJohn]

Hi Matt,

Any suggestions on how get rid of the birds nest as it relates to the speeds, feeds and DOC in 6061T6? Or insert tooling for that matter.

[Jawbreaker38]

Originally Posted by HelicopterJohn Hi Matt, Any suggestions on how get rid of the birds nest as it relates to the speeds, feeds and DOC in 6061T6? Or insert tooling for that matter.

For breaking chips the biggest factor is to bury the nose radius of your insert. So for example, if you're using a 1/64" nose radius on your turning or boring tool then you need to be cutting at least 1/32" on your diameter.
I run 6061 and 2024 everyday and rarely have an issue regardless of the insert as long as I have the radius burried.

[HelicopterJohn]

Hi Jawbreaker38,

Thanks for your valued input. I am sure Vern will give that a try if he hasn't already.

[Geof]

Sometimes it is difficult to get rid of long stringy chips even by pushing the DOC and feed. The GT10 may not have enough torque if the part diameter is too large.

An alternative approach when roughing is to use G74 or G75 to actively break the chip.

[roundman]

I must cut jaws on a regular basis. I use collets whenever possible first choice. I use a set of rings I bought and of course a piece of turned material can also be used for chucking the jaws under pressure and cutting the diameter of whatever you are holding. You can bore a id back into the jaw "short" of running into your ring clamped in the id. Your minimum id and clearance for your boring bar will be the diameter of the ring or material you chuck on. Use the same pressure to bore your jaws and to hold the part to be held. Bore to size or when with the ring still clamped you check to see if the part you wish to clamp will fit in. Before removing the jaws after use I mark each one with a scriber jaw1 jaw2 jaw3 and for alignment. I store them for future use by clearly taping the three together and marking the part number part or customer name on the masking tape. If I cut jaws to hold a diameter which I consider to be the size of the material I will write on the tape 5 inch or whatever because sometimes I can use those jaws for some other job which has material 5 inches in diameter and aviod cutting jaws again. I want to learn more about using the pins and ring to cut jaws though. Oh sometimes I might need some relief in the corner id so the part will not cock. Or you can make sure the clamp end of your material has a chamfer on it.If you want jaws machined without a shoulder then you can cut away the step by removing the ring and changing your chuck setting to id chuck and gently bore it off. You can even remove the jaws after marking them 123 and cut off the step with an endmill on the manual mill. I hope this helps and makes sense. If not ask me about it on a day that I feel younger!
Good Luck

[Vern Smith]

I appreciate all the help and suggestions. I've been busier than I like to be but now have time and tooling to get back to the lathe project. everyone seems to agree that I need more feed and depth of cut to avoid the bird nests. Funny someone would mention an Atlas lathe as that was my first machine tool. I put new spindle bearings in it and someone had inscribed a date on the face of the outer race and as I recall it was 1942.

The chucking problem was soft jaws. I took a washer and clamped the fixed jaws down on it, bored the OEM soft (steel) jaws and all was well. I did run into one little problem. When I stomp on the foot pedal and the chuck closes I don't always have the bar (6061) positioned on dead center. The result is that 2 of the jaws like to capture the bar on the way closed and scar it up in the closing process. I'm sure this will not be a problem when feeding the bar through a spindle liner but what do you do when you are putting slugs into the jaws from the front?

The machine came with 3 of Haas' 1" ID tooling blocks. Are these available from several suppliers or are they proprietary to Haas?

Vern

[Geof]

Originally Posted by Vern Smith ..... When I stomp on the foot pedal and the chuck closes I don't always have the bar (6061) positioned on dead center. The result is that 2 of the jaws like to capture the bar on the way closed and scar it up in the closing process. I'm sure this will not be a problem when feeding the bar through a spindle liner but what do you do when you are putting slugs into the jaws from the front?....Vern

You can minimize or even avoid this happening if you bore the jaws when they are almost at the limit of their open travel. This way when you open them after boring they only move a small distance so there is not enough room for the bar to wedge between two jaws. Couple this with boring them out so the entire width of the jaw is involved in the grip and they behave much like a collet.