Hardinge CHNC conversion

[N4NV]

I have been working on the lathe for a couple hours every day since my last post, but there was not much to show. I have added 5 coats of primer, the last two being white. I learned this technique from some guys that build home made airplanes. When I sand the last coat of white primer, I can tell how deep I am sanding because the darker rust color will start to show through.

I applied the first finish coat with an airbrush. I thought it would take forever, but it only took about 1/2 hour. I used an airbrush because I don't have enough air to use my HVLP gun. It worked out much better than I thought it would. I was a little light in some spots, but that will cover up with the second and third coats. My main concern was runs.

In between coats of paint I have been scraping and cleaning the other parts of the lathe I have removed. It seems to take most of an hour per part to get them clean. Mineral spirits and naphtha don't seem to touch the grime. The saddle is all cleaned up and ready to re-install. After cleaning the ball screw covers, I plan on using some Casewell's black oxide to re-color them black. I will also coat any of the steel bearing blocks black. If the bearing blocks don't come out well, I will just paint them black.

Vince

[N4NV]

I had a little more time to kill tonight so I welded up a casting that was broken off the lathe. This is the housing between the lathe bed and the caterpillar track that carries all the electrical, oil and pneumatic lines to the carriage. It was broken in two places, one entire edge and one corner. I had spent several hours on another day cleaning and stripping it of paint. Even so, it was still a pain to weld. I just could not get it clean enough. I had to use a method a friend of mine calls "pylon” as in "pile it on".

After welding I ran a bull nose mill around the perimeter to clean it up a bit, then a face mill on the mounting flange side.

Vince

[N4NV]

More painting and cleaning today. I think I will put on one more coat. I can't believe how well the paint is going on with just an airbrush. It is so smooth it is almost like a mirror, no runs (yet). I repainted the top of the stand as well. Prior to the finish coat I sanded it with 220 grit sandpaper. The sanding marks showed up through two coats of paint. I re-sanded with 400 grit and re-painted, again with the airbrush.

As soon as I mount the lathe on the stand, I want to get the spindle turning so I can make sure it is OK. I tried several places and no one could figure out what type of belt it takes. I gave up and ordered a set from Hardinge. When I get the belts, I will take them down to the belt and pulley store and see if they can match them to a three grove pulley I need for my drive motor. I have a 5 HP 1750RPM I plan on using to drive the spindle. I want to get a pulley that is smaller than the one on the spindle so I can get more torque at lower speeds. I can turn the motor at 200 HZ to get the top end speed. I am more concerned for a speed around 100 RPM.

Vince

[kipdidit]

Looks like I will be looking at this thread alot. I've got the same machine (in about the same condition but without a base) that I'll be starting on shortly, so don't spare the details!

Kip

[N4NV]

I think I put the last coat of paint on the lathe today. I might need to touch something up if I scratch it during the installation.

I got to thinking about all the other castings and things that will also need paint. It seems like the painting will never end. I cleaned up the lathe bed end casting (the one that holds the carriage ballscrew). It will be ready for paint tomorrow. I started on the cross slide end casting, cleaning it anyway. I don't think I will paint it yet. This lathe had the servo motors stripped off and unless I can find some original, I will have to drive it with servo motors I have. This will require me to mount the motor on the right side of the cross slide, which will then require me to machine a slot in the side of the casting for the timing belt to get to the motor. The motors I have are too long to use in the original position. If I mount them 180 degrees to the original they will hit the enclosure I plan on building.

Anyway, I removed the cross slide limit switch and rod (picture below). This is where I found a lot of sand and gravel earlier.

I received some Boeshield T-9 today and plan on coating all the parts with it until I can get them installed. My Caswell blacking kit came today as well. Hopefully I can try it out tomorrow.

Vince

[BobWarfield]

Looking good, Vince!

I love your paint and body work. Did you ever consider powder coat for more durability? Seems readily available, though it won't shine like your paint does.

Are you sticking with the turret changer, or are considering a gang plate?

Best,

BW

[N4NV]

Originally Posted by BobWarfield Looking good, Vince! I love your paint and body work. Did you ever consider powder coat for more durability? Seems readily available, though it won't shine like your paint does. Are you sticking with the turret changer, or are considering a gang plate? Best, BW

You can't powder coat it because the spindle has permanently sealed bearings. I have read and been told you can't take the spindle apart and get it back together. It takes special tooling. The 400 degree bake for the powder coat would certainly ruin the lubrication of the bearings.

The CHNC I have only has a 4 1/2" X travel. That is not much for gang tooling. I really hope I can get the turret working.

Vince

[BobWarfield]

Vince, unless there is something peculiar about this particular Hardinge, you can definitely take the spindle apart. See Gunner's article, for example:

http://aafradio.org/garajmahal/Hardi...eplacement.htm

I've read several accounts of folks who were 100% successful following his approach.

With that said, the paint looks great, you're past that point, pray continue.

WRT gang tooling, there's might be more gang tooled Hardinge conversions that anything else. If I were going to attempt it, I would create an AccuSlide-like axis. What they did is to build a linear-slide + ballscrew stage that just clamped to the Hardinge ways. The dovetail ways are perfect for it. In this case, you don't need 2 axes (I assume), so you'd build it to attach to the saddle. Pretty simple to construct, the linear slides give good performance, and you get the extremely fast tool changes inherent in a gang lathe without the complexity of an automated turret.

I have some information on this on my site:

http://www.cnccookbook.com/CCLatheCNCGangSlide.html

I know the manuals for the Accuslide are available somewhere on the net and have exploded diagrams, but I don't recall where.

Just an idea to consider.

Cheers,

BW

[N4NV]

I looked at the site for replacing the spindle bearings, but it does not sound like what I see in my CHNC.

I stripped off the masking tape today. Don't go cheap like I did and use regular masking tape, spring for the blue stuff. The tape was a pain to get off cleanly. After removing the tape, I installed the carriage. I might even be able to mount the lathe to the stand this weekend.

In the cross slide there are various studs and holes. I figured out what they all are but two. In the picture below, the one with the question mark looks like a broken stud. The other one is a stud that had an Allen head underneath and is accessed from the bottom gear bolt hole. Does anyone know what they are for?

When I was removing the center carriage ballnut housing, one of the alignment studs broke. These studs are threaded 10/32 so they can be removed by threading in a long 10/32 screw and pulling them out from above. Anyway, I broke one off. It broke slightly below the sruface. I tried drilling it out but it was hardened. I ended up tig welding a 10/32 screw to it and pulling it out. There was absolutely no damage to the housing from the operation as you can see in the picture below.

Vince

[N4NV]

I got a chance to try my Caswell black oxide kit today. The covers for the carriage ballscrews were originally a black oxide finish. On some of the covers it was completely worn away, others not much. I ran them all through the process which consists of a dip in the black oxide solution (at room temperature, and actually an aqua blue color), then a rinse, followed by the fixing solution. The kit came with two cans of fixing solutions. I also ran several of the bearing blocks through. I want most everything to have paint or black oxide to cut down on corrosion. In the pictures below are the buckets of solutions and the finished parts that are still drying.

Speaking of paint, I did some more of that as well. I really can't say enough about the airbrush for these parts. It has been putting down a very nice coat of paint. I spent way to much time looking for loose parts. I should have been much more meticulous when I was taking things apart, like bagging and labeling everything. Just going through all the screws is going to take time. I did start bagging a little more than half way through.

I found 5 more parts that need paint, covers plate, end plates etc. I need to get them cleaned up and prepped. The cross slide bellows are pretty gunked up as well. I started them soaking today. Maybe by tomorrow I can get them cleaned up.

Vince

[Runner4404spd]

Most of the older CHNCs run straight oil as coolant and not the watersoluable stuff. i would contact hardinge as there was a change somewhere around production number 4300 that allowed the use of soluable coolant. previous to this production number all lathes use oil as a coolant and lubricant and i hope your planning on doing the same.

[N4NV]

Originally Posted by Runner4404spd use oil as a coolant and lubricant and i hope your planning on doing the same.

Yes, I plan on using oil. With the amount of use my machines get, I have had a terrible time with water soluable oil.

Vince