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Another Hardinge retrofit, this time it’s a older Chnc. This is my first retrofit, and I was originally planning on doing an even older hardinge Ahc. However I ended up winning a eBay auction for a Chnc that should be much easier to retrofit. I paid $525 for the lathe, 3 control cabinets and a hardinge bar feeder. Shipping however kind of soured the whole deal, I ended up getting the lathe shipped from Ohio to Reno Nevada. Total for the lathe with shipping was around $2k. I should of just left the control cabinets in Ohio, as none of them start, just dead weight, lol. Luckily the lathe came with a lot of documentation, I have all the schematics for pretty much everything.

I plan to retrofit the lathe using linux cnc in 2 stages. Stage 1 will be to get the lathe working using the original Hi ack servo amps and spindle motor. Stage 2 will be retrofit to 1.5kw ac servos for x and z, and 4kw C axis spindle. I have already tested the x and z axis amps with a AA battery and they seem to work good, the z axis smoked a few isolation caps, but still works. I will be replacing the caps as soon as Digikey ships the replacements. I have yet to test the spindle motor. I think If I understand correctly I need to force on the spindle brake relay, to release the brake, and then I need to ground the Inhibit pin to be able to test with a battery.

I will be using the Mesa 7i33, 7i37 and anything io 5i20 cards for control. I still need to find a good motherboard and processor for the panel pc. Will be doing a 5 wire restive touch screen with a 15 or 17 inch monitor for pc interface. I think I will be replacing the resolvers and tach with a Us Digital differential 2500 ppr encoder , since It will be cheaper than the resolver converter boards on the market. The only problem I see with that is the current amps have a 6v tach signal feedback, and I don’t know if the Us Digital encoders can provide 6v tack signal. I’m not sure if I even need the tach feedback at the amp?


encoder link

usdigital.com/products/encoders/incremental/rotary/kit/EC35

Red is where the tach feed back is at the amp, that terminal block is the amp input terminal.

it's a pretty straightforward machine to convert , Mesa do a resolver and analog servo conversion that will suit the resolvers , far easier than replacing the resolvers erc
you'll need a lot of IO , but over all not a bad machine to convert .

i'd go with using the existing drivers , nothing wrong with them if they are working , it's a major job to replace them .
the majority of problems with the older electronics are as you have found dry'd out caps , but once you replace them with more modern ones they run fine .

some spindle motors do not have the brake fitted .
check out all the axis and the spindle motor using a 3v dc battery supply , theirs an actual test circuit in the manual using a pot , which works fine too .

Alloy Craft wrote:
The tach feedback to the amp is needed so the amp knows how fast the servo is turning vs the commanded velocity. If the tach is not a separate device you could leave the resolver/tach and just add the encoder.

Sure looks like a HNC not a CHNC unless the first CHNC's looked like HNC's...

My CHNC I

gnipsel.com/shop/hardinge/hardinge-18.xhtml

$1500 for shipping from OH to NV don't sound too bad, maybe a couple of hundred high...

John

Alloy Craft wrote:
Use the Mesa 7i49 instead of the 7i33 and you can keep the existing resolvers.

It's a bit more expensive, but likely to be far easier. Resolvers are nice things.

The Hiacks you have seem to have had the top boards replaced,as the originals were not dark green,they are a brownish yellow.I have a Hiack manual with schematics if you need a copy.They are easy to fix.They are a velocity amp and do require tach feed back though and by todays standards are not very effectent. The spindle motor is a dc brush motor made by porter peerless.They still support their product.Dont even try to get Ge or AB to help you,as most of they guys who knew that stuff are long since retired and GE will charge you 185.00 an hour for support!!.


The only real differences between a chnc and an hnc are the hnc had a GE550 NC control and a mechanical variable speed spindle drive.The chnc had an AB 7370 true cnc and a servo spindle drive.The chnc was more expensive.My sources tell me the AB is a bear to keep running and that Hardinge wanted a low cost control from Ge and the only thing ge had at the time was the then outdated,but rock solid 550T.The full size 1050t was to expensive and the 1050h wasnt available yet.Hardinge did use the 1050H on HLX machines ,but I have heard they didnt intregrate it very well and they had problems.

I saw the same machine on ebay and almost bought it,didnt have the room!!!

hey J.R.


would you be interested in telling me how you tested your axis drivers

mine look the same as yours but my lathe is a little different, instead of the control being behind the lathe it is connected by braided cable/conduit I am in the process of trying to upload photos.

they are hiak and are mounted in the large control cabinet. I would like to test them before deciding whether to replace them



thanks


bob