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Is 36-HC a good chuck? (Hardinge 4-jaw 5")

Frigzy

Aluminum
Joined
Apr 26, 2018
I'm looking to buy a good 4-jaw chuck for a tapered-nose Hardinge HLV-H clone. It's going to be a once-in-a-lifetime purchase, so I'm asking for advice. Is 36-HC a good buy or may be there are better options around? I thought about making an adapter plate and buying a non-hardinge mount chuck. I'm only concerned about length and weight of such assembly - I'd like to run the spindle at 3000 RPM.

Thanks!
 
If it's an original Hardinge chuck then of course if it's in good condition it will be 'a good buy'. Assuming it's what your looking for.
 
Those chucks were made in England by Pratt-Burnerd quite a few years ago. They are OK, but the only special characteristic is the short overhang because of the taper machined into the rear of the chuck. I have seen several examples of the female square in the jaw adjusting screws cracking. Some years ago, PB said they no longer had replacement screws, but I still have one or two new screws.

Larry
 
The problem is - I'm not sure what I'm looking for. My other chuck is a 6" Buck adjust-through and I really like it. I don't have much of machining experience - before a Hardinge clone, I had a chinese tiny mini-lathe with 4" chucks. Does 5" 4-jaw feel like a right size for a Hardinge?
 
Hardinge sold those 5" chucks (3, 4 and 6-jaw) with one-piece jaws because they suited their lathes. They also sold 6" 3 and 6-jaw chucks with two-piece jaws for customers wanting to use soft jaws and wanting more capacity. You do have to be aware of max RPM limits on chucks when using a high speed lathe. In general, only rather new chucks have the limit marked on the chuck, but some makers list the limits in their catalogs.

Hardinge is now selling Buck Ajust-Tru chucks on their web site and they have the taper mount adapters for them.

Larry
 
Thank you everybody for the information. I went ahead and ordered the chuck. It was $225 including the shipping. Will see if I like it. Hopefully, I can sell it if I don't.

Can anyone please measure the female hex bore in the set screws? I want to entertain myself by making a chuck key while it's getting delivered.

ebay link: https://www.ebay.com/itm/153326485221
 
As the comment in the ebay listing indicates, the screws aren't original. The originals had a square socket, but as Larry says, the square sockets tend to split. My chuck is in this state and I'll get around to rebuilding the chuck, jaws and screws at some point in the future.

As to what size chuck is the right size for a Hardinge, it depends entirely on what work you are doing. Obviously, they excel at collet mounted work, and for a general purpose lathe, this sort of size is probably 80-90% of what gets done. I have found the Hardinge 5" chucks to be fairly limited when stepping up to larger work, but that's because The HLV is my largest lathe and sometimes I want a bigger one! With care, you can mount an 8" chuck on a Hardinge, provided you take the maximum safe speed for the chuck into account and are aware of the risk of running the top slide, carriage etc into the chuck.

Here's one I prepared earlier. Note the split screw on the Hardinge chuck's topmost jaw:-

chuck.jpg
 
Thank you everybody for the information. I went ahead and ordered the chuck. It was $225 including the shipping. Will see if I like it. Hopefully, I can sell it if I don't.

Can anyone please measure the female hex bore in the set screws? I want to entertain myself by making a chuck key while it's getting delivered.

ebay link: https://www.ebay.com/itm/153326485221

I think you paid $200 too much for that chuck because you cannot buy a new set of jaw screws to return it to useable condition. Someone silver-brazed heads of socket head cap screws onto the ends (split, we can assume) of the original jaw screws. The red heat of brazing drew the temper of the hex heads and the screw threads, leaving them too soft to endure any normal use without failing.

Back in the late 19th century, it was normal for jaw chucks to be built with the jaw screws or adjusting devices extending out past the chuck body. It became obvious that the practice was a safety hazard and, for over 100 years, new chucks have the adjusting devices flush with the chuck body.
 
Someone silver-brazed heads of socket head cap screws onto the ends (split, we can assume) of the original jaw screws.
That's just terrible. I should have posted the link here before buying. Am I screwed?
 
late to the party but


I have a couple of the 5 inch chucks , both with cracked screws thanks , I think , to people using the chuck key to remove the chuck rather than normal operation . ( drill a shallow hole on the collar and use a c spanner to remove the chuck) It would not be too difficult to make a set of screws , I'm surprised there aren't third party ones available.

I also have a 6 inch 4jc which has the taper bored partially into the chuck that uses a steel adapter . I find this a much more useful size .

https://www.practicalmachinist.com/...g-chuck-hardinge-hlv-h-em-202456/#post3129988
 
That's just terrible. I should have posted the link here before buying. Am I screwed?

The chuck should be usable. If you can keep your hands and tools away from the protruding screw heads when spindle/chuck is turning.

Or you can try and return the chuck. Seller states no returns, and he mentioned the replaced screws in the listing. So not sure you have any options.
 
Thanks God - seller turned out to be a nice guy and agreed to cancel the purchase. So the chuck should be up to sale again if anyone is interested (hmm.. was that the point? just kidding ;) ). So I'm looking for a chuck again. What to look for?

Thanks!
 
I think that the hex screws is a reasonable effort for a repair. Get your machine working and use it to make replacements. Turn the thread, cut the groove and make a wobble broach for the square hole. It would be a neat project.

I got a near mint one off eBay last year for £160. It's a bit small but what you going to do when they are so hard to find? I'm looking out for a slightly larger one, might even turn a backplate and get a plain-backed one.
 
36-HC chuck is fine. If the ebay listing doesn't show good clear shots of the four squares for chuck key, ask for them. The cracks start out small and propagate from the corners of the square. P-B did come out w/ replacement screws which have more matl in the corners. As stated previously, they are no longer available.
 
BTW: if I buy a chuck or an attachment for a hardinge threaded spindle, how difficult would it be to convert it to a non-threaded (tapered) spindle?
 
BTW: if I buy a chuck or an attachment for a hardinge threaded spindle, how difficult would it be to convert it to a non-threaded (tapered) spindle?

Have a search for Frank Fords site, ISTR he was able to turn the 4° taper into the threaded part without too much difficulty.

The taper is not difficult to cut if you have some wayof holding the chuck. I just put a bar into a collet , clamped and centred the chuck onto the bar and turned the taper .

HomeShopTech
 
Wait..is your bed scraped?:eek:

Sorry for the late response! It isn't scraped, it's spot ground and lapped. When I rebuilt the lathe, I didn't have access to a large enough surface grinder to do the bed in one pass and my too-small surface grinder is too worn to get the desired flatness when doing the bed in two passes (not because the SG ways aren't straight enough, so much as the scraping on them has worn smooth over its life, which causes the bed to ride up on a bow wave of hydraulic oil when changing from left to right and vice-versa). Because the bed is 'file hard', scraping is a painful and futile experience, but a die grinder or even a Dremmel can be used with a different technique and the right stones to achieve the same results that scraping would on a softer material.

I plan to rebuild the surface grinder in a couple of years if I live long enough :D.
 








 
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