Help ID'ing Power Chuck on Hardinge CNC Lathe?

My 1993 Hardinge Conquest T51 came with an 8" power chuck, which needs new master jaws. But I'm having trouble finding where to order them.

The chuck looks very much like an older Hardinge Sure-Grip chuck [1], but it's not marked with the Hardinge logo, nor with a Hardinge part number. In fact, I don't see a maker's mark on it anywhere. So, I expect it's a knock-off, but don't know how to determine the maker. Here are a couple pictures:





(You can click on the pics for high-resolution versions.)

There is one number, "17514", stamped on the face of the chuck; I reckon that's a serial number.

Any suggestions on how I might proceed? What would you do in this situation?

Thanks!

Jim

[1] The images of Hardinge Sure-Grip chucks on the Hardinge web site and in their brochures have only 3 chuck mounting bolts. Click here for an example. However, I found one picture on the web (click here to see it) that has 6 mounting bolts, and looks more like mine. I assume the latter picture is out of date, and that's why I'm guessing mine is like an "older" Hardinge Sure-Grip chuck.

looks like a powerhold. they supplied hardinge with chucks before hardinge made the sure grip. the jaw serrations are 1/16 x 60deg. powerhold is still around do a google search they have a website, don't know it off the top of my head.

@chip_maker: Thank you for the info! I found their website / phone number; will give them a call in the morning.

Cheers!

Jim

After you catch your breath from hearing the price on any power chuck parts, you'll likely want to start checking Ebay for a chuck. Over the last couple years I've bought a 6" SMW with hard jaws and an 8" MMK (matsumoto), both new in the box, for a total of $600. I was sorta looking but not searching on any regular basis for them, and still found both of them over a fairly short time span.

If you're looking at replacing parts based on wear, that's something that is hardly ever worthwhile on smaller power chucks. Wedge chucks (most common type) are amazingly simple. But that same simplicity makes them sorta done for good when they have wear issues. If you needed master jaws due to wear on the tongues that engage the wedge, then you'd likely need the wedge as well. That's all the moving parts in a power chuck. If you needed them due to wear where they slide in the body, then there's likely equal or greater wear in the body. Once again, not much of the original left if you replace all the worn parts.

If you look for a chuck on Ebay, you'll likely find some selling for near nothing. Look closely because they probably have an oddball serration pattern on the master jaws. Inch based V serrations are much less common than metric, and some of the square groove patterns are less common still. 1.5mm serration pitch is sorta the standard, and you'll pay far less for the corresponding soft jaws due to their widespread use. If I was looking for an 8" chuck, I'd further narrow the search to ones with top jaws that will interchange with Kitagawa top jaws, because that standard is the one where you'll find the greatest range of available top jaw sizes and configurations at the most reasonable prices.

I would imagine your lathe has an A2-6 spindle nose. On -5 and -6 noses its not uncommon to see 3 bolts used as well as 6, depending on the chuck. Anything larger always has at least 6 bolts from everything I've noticed over the years. Obviously you'd want to remove the existing chuck for verification, but every spindle nose I've ever seen will have the full complement of bolt holes, so a 3 bolt chuck could be replaced with a 6 bolt one.

metlmunchr said:

After you catch your breath from hearing the price on any power chuck parts, you'll likely want to start checking Ebay for a chuck.

Click to expand...

You are so right. $1,835.00. Youch!

Wear isn't the problem. A long time ago, in a place far, far away, some yokel replaced one of the master jaws. The serrations on that jaw are shifted from the other two by about 0.025". If that were the whole story, it wouldn't be a big deal; I could number and grind the top jaws, and be off to the races.

However, although the serrations are 90-degrees, the spacing is not exactly 1/16". It's not 1.5 mm, either. What it is, I don't know, but it makes a bad fit to the top jaw, which consequently "rocks" on the serration. I don't think I can tolerate that, given my CDO gene. (That's OCD, but in alphabetical order, like it should be )

I glanced at what's on eBay this morning. The 8" chucks I saw looked like they had smaller through-holes. My chuck has a 2.050" opening, which is good, as I will need to be able pass at least 1.75" bar stock through.

Thank you for the suggestions about jaw sizes. Sounds like good advice.

Cheers,

Jim

I agree with 'Muncher. Search Ebay for: Kitagawa, Matsumoto, Howa, and power chuck.

You should be able to find a new 8" for under $1k.

'Muncher's right again on the mounting. Virtually all 8" chucks will have an A2-6 (or A1-6) mount. 3 bolts or 6 bolts doesn't matter...they will bolt up.

Good luck!

I should sell you my Hardinge chuck like that - exactly for your machine!

I got it new with my machine and only ever mounted it a cpl times. But then I would have a good job for it the next week.


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Think Snow Eh!
Ox

Metlmunchr gave you good advice. Here are links to Kitagawa and MMK(Matsumoto) pages so you can identify what you find -

Kitagawa Workholding Products

Power Chucks, Cylinders, Workholding Equipment from LMC Workholding

I'd definitely stay with those 2 brands. My favorite is MMK, but there's not a great difference. I've experimented with Powerhold and Howa, the best of the "other" brands, and parts and jaws are scarce. The bad news is you hardly ever find 1/16X90 jaws, the good news is when you do, they are giveaway cheap. You need to be sure of your drawtube size to get the right chuck. Like munchr said, it's scary how cheap you can find them brand new on ebay if you are patient. I believe Milacron has some new 8" power chucks, might be worth a PM to him for info. Here's a link to US Shop Tools, a little browsing will show you how many odd chuck jaw configurations there are.

Chuck Jaws by U S Shop Tools

Ox said:

I should sell you my Hardinge chuck like that - exactly for your machine!

I got it new with my machine and only ever mounted it a cpl times. But then I would have a good job for it the next week.

Click to expand...

What are you using instead? A collet setup?

If you're serious about parting with it, PM me.

Jim

@ metlmuncher, cnctoolcat, Mud: Thanks, fellas. Sound advice, it seems. I've got my eyes peeled. Meantime, I'll start with oversize stock.

Yes - I run an S-20 master with 2-3" extension to get some headwall clearance. But my headwall still has many holes and bulges in it.

I have about a million cycles on that master collet and have a spare setting there - waiting for it to die one day.


I don't think I am serious about selling it at all - just seems .... well ....


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Think Snow Eh!
Ox

....but it makes a bad fit to the top jaw, which consequently "rocks" on the serration.

Are you sure that your jaw bolts aren't to long? Looks like they have been bottoming out in the master jaws.

Thawk53 said:

Are you sure that your jaw bolts aren't to long?

Click to expand...

That’s a really good observation. I looked at the pictures yesterday and didn’t even notice that. I think you are right, the bolts have been bottoming out on the master jaw.

Regards Phil.

Thawk53 said:

Are you sure that your jaw bolts aren't to long? Looks like they have been bottoming out in the master jaws.

Click to expand...

machtool said:

That’s a really good observation.

Click to expand...

Yes, it's an excellent observation! It appears that was indeed a problem sometime in the past. However, none of the bolts hit bottom now, nor have any since I got the machine. The "rocking" happens (even with no bolts in) because the serrations on the top jaw don't mesh exactly with those on that one master jaw. That mis-mesh looks to be caused by a slight difference in pitch between the two.

I'll see if I can get a close-up, just for curiosities sake.

Cheers!

Jim

Ok, here's a pic of the mis-mesh:



Ignore my Sharpie marks. I was counting teeth to multiply for a more accurate pitch estimate. But you can see the master jaw serrations (top) are a tad wider than those of the top jaw (which, paradoxically, is at the bottom of the photo ). It's clearer in the higher-resolution photo (click on the pic to see that), especially if you pay attention to the extreme left and right.

I don't know what the pitch on that master jaw is. 1.5 mm is finer than 1/16".

I'd say that's just a manufacturing screw up, someone ground the serrations wrong.

McKean Machinery Sales, Inc - Inventory Search Results



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Think Snow Eh!
Ox

Thanks, Ox!

I didn't notice that this chuck was a blind hole.

I wonder if the draw tube can be changed?


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Think Snow Eh!
Ox

Ox said:

I didn't notice that this chuck was a blind hole.
I wonder if the draw tube can be changed?

Click to expand...

Dunno. This one on ebay looked good, too, but the through-hole is too small.

8" Dia. 3 Jaws Kitagawa HOS-8 LATHE Chk - eBay (item 150415865176 end time Mar-20-10 22:14:09 PDT)

I think I'm gonna hafta live with what I got for a while. There's other fish to fry, first. I'm making good progress, tho. I'll post here when I get I get a bigger minute.

Jim