Hardinge taper nose chuck locating pin

Like an idiot, I have broken my Hardinge HLV 3 jaw chuck location pin. There is a location cap on the circumference of the chuck over the pin, which I have removed, but I cannot see how to remove the old pin as it is way down inside the hole. Any ideas?

I have a new pin which I think may fit, but am unsure if it is correct one. Does anyone have the dimensions of these pins so that I can check? Does anyone retail them?

Russ

I have never had one out but I am fairly sure that it is an Allen screw with the end ground at an angle to make a key shape. It is locked in with a second "jamb" screw. When you tighten the jamb screw it will want to rotate the key screw, might take several tries and maybe a couple of tricks to do it right. I bet you will get several hints in short order from someone that has actually done it.
Hardinge will have the screw, and it is probably the same one for all models.
Whoops, I thought you needed the internal 5-C key.

I had to make a couple of them a while back for 5" chuck adapters that were not made by Hardinge. The adapters were great, but they had very badly made pins. The pin is made from a 5/16" x 1" steel dowel that slides into the hole. On these adapters, the pin is locked in the hole with a 3/8-16 flat point hex socket set screw. I turned the end of a cup point screw to make a flat point and leave the top of the screw just below flush with the adapter.

I have one that I made in front of me and the turned-down diameters are .249" and .155", but the lengths and pin size may vary with the maker and size of individual chuck mounts. The little end has to project about 1/8" into the spindle slot.

This design with the hard pin and set screw retainer is only used on the Buck Adjust-Tru adapter plates and the Pratt Burnerd Setrite adapter plates and maybe some Chinese copies where the pin enters the adapter at a point on the 5" or 6" diameter of the adapter. Adapters with the pin located through a small diameter hub use a special oval point screw with a dog point.

I just took the pin out of a genuine Buck 5" adapter. The diameters are .310", .249" and about .157". The screw is 3/8-24 x 7/16" flat point. The pin is softer than a dowel and has some distortion on the small end. I like the dowel pin as raw material better, but you do need a sharp carbide tool and a high speed Hardinge lathe to do the turning.

I have another no-name 5" adapter plate. The pin is turned from a 3/8-24 x 7/8" set screw with the .249" and .157" turned down sections. The position of the .249" shoulder controls the depth of the pin in the inside of the adapter. You simply run the screw all the way in and then lock it with the outer set screw. There is no fiddling about with the inner screw position once it is made to the correct dimensions.

You first remove the set screw and then push the pin out the hole from the inside. A 3/16" hex key, also used to remove the set screws, is a convenient tool for pushing the pin out.

Larry

MSC P/N 60110582 about $31
Good luck

To add to all the other combinations mentioned by Larry and others, I have some Hardinge chucks that the pin is just a screw with a turned dog point on it.

Sounds like yours (OP) might be the type that screws or slides down to a shoulder, though.

smt

Thanks everyone

Thanks everyone. I just hope it is not stuck in. Russ

Here is a drawing made from a brand new Hardinge pin:

Well I got to it today and drilled through the bottom pin and using an "easy out" unscrewed it from the chuck. FredC was correct about the hex in the top of the pin, save that my pin was black with years of oil and this had carbonised, gluing it into position. So these are the two pins. The bottom pin sits on a shoulder and appears to be much longer than Jims great drawing. The threaded part of the pin is 5/16" long, 1/8" between shoulder and thread and the pin 15/16" long without the broken off section.

Hopefully this will be of use to someone in future years!

Russ

This is another illustration of the futility of supplying detailed dimensions or drawings of these parts. As I indicated when I described three different pin designs from three chuck adapters I had handy, the diameters seem consistent, but the lengths and presence or absence of threads need to be tailored to fit your adapter. Keep in mind that Hardinge did not make jaw chucks or chuck adapters, so every chuck company or sub-contractor could design their own locking pins, keeping only the bit that enters the spindle slot to spec. You will find chucks with the Hardinge name on them, but they will also be marked "by Buck" or "Made in England" (by Pratt Burnerd).

Larry