[N4NV]

I ordered and received enough O-rings from Hardinge to rebuild the collet closer. You can see the process in the pictures below. When taking the piston housing apart, use a little compressed air in the port to separate the housing. Don't use much or you may blow it across the shop. There was nothing too special about replacing the o-rings. While I had it apart I took the time to polish the housing. Because of the design of the collet closure there will always be air leakage. The part of the closer that has the inlet and outlet tubes does not have any o-rings as seen in the 4th picture. The only thing that seals it is the oil in the air lines so you will always have an air lead through the MAC valve as well as air leaking around the shaft of the closer.

[N4NV]

When I got my CHNC I started looking for some chucks for it. So far I have only found one, a 6 jaw. I have had it for almost as long as the lathe and up until a few weeks ago, I did not have a chance to use it. When I did start using it I found that it was badly out of parallel with the lathe bed. I check with some collets showed that the headstock was parallel to the lathe bed and the chuck as definitely out of skew.

I posted my predicament over at the Practical Machinist and received a lot of answers, a couple of them useful. Here is that thread:

http://www.practicalmachinist.com/vb...d.php?t=175951

Here is the link to the site that showed how to grind the jaws:

http://www.homemetalshopclub.org/new...04.html#truing

I took the advise of JST and went to a web link he posted. I followed the instructions about mounting a pencil die grinder to do the grinding. I cut 6 identical pieces of Delrin and put them between the jaws and tightened them. I did not need a ring. I ordered a cheap pencil die grinder (56,000 rpm) from eBay $25 plus shipping. The die grinder was 5/8" OD which fit perfectly into my turret tool holder on my CHNC. I ran the grinder back and forth about 20 times an removed about .0015" total. I installed the test bar again and get +-.00015" at the chuck face and +-.00015" 6" from the face with two different test bars. See the attached picture for the set up. Now that I have seen how well this works, I will not hesitate to do it again if I ever get another chuck with this problem.

Vince

[agwelder]

Hi Vince,

Looks like you've done a really nice job on your Hardinge. We retrofitted an HNC last year had trouble using the Hall effect limit switches with our setup. Our frustration was to the point we changed to mechanical switches and moved on. We are building another HNC with PMDX BOBs and we would like to use the existing limit switches. If it's not to much trouble, could you give us a rundown of how those are wired in?

Thanks in advance, Adam

[N4NV]

Hi Vince,

Looks like you've done a really nice job on your Hardinge. We retrofitted an HNC last year had trouble using the Hall effect limit switches with our setup. Our frustration was to the point we changed to mechanical switches and moved on. We are building another HNC with PMDX BOBs and we would like to use the existing limit switches. If it's not to much trouble, could you give us a rundown of how those are wired in?

Thanks in advance, Adam

The sensors are really easy to hook up to the PMDX board. The black wire from the sensor goes to the ground of the PMDX, the red wire connects to the +5 auxout, and the white (signal wire) terminates on the input you want to use, pin 15, 13 etc. No need for pull up resistors. They can also be paralleled without any problem. All of my Hall switches are paralleled on each axis.


Vince

[sbalder]

I've just come across this thread, and have read through all 25 pages. I admire your deication, and I especially appreciate you taking the time to post so regularly. Nice work!!!!

[BobWarfield]

Yeah, this was a cool thread.

Vince, do you still have the lathe and is it working well for you?

Best,

BW

[N4NV]

Yeah, this was a cool thread.

Vince, do you still have the lathe and is it working well for you?

Best,

BW

Thanks for the kind words. I still have a lot I want to do, but at least I can use the lathe now.

Vince