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Adjusting/repairing Z travel on Pacemaker?

ions82

Stainless
Joined
Nov 1, 2006
Location
ABQ, NM
Hello!

I am in the process of cleaning and adjusting the 16x30 Pacemaker that I recently acquired. I noticed that the handle moving the carriage along the Z-axis will slip if it is met with any resistance. I assume it is a safety feature that is meant to prevent catastrophic damage. If this is the case, it feels as though it may be a little TOO forgiving. Before cleaning, the carriage movement was a little sticky as the lathe had been covered in grease before storage. At one point, I couldn't traverse along Z because the carriage had stuck (and the handle just spun). Is it indeed just a safety feature that may need adjustment? Or, is there something wrong that will need repair? If anyone has any advice that may be helpful, please post. Thank you for your time!
 
Longitudinal travel:

Looking at assy drawings there are two keys - likely one is sheared from some doofus "helping" the carriage along.

One key in handwheel - an easy to get to one.

One key in spur gear that hand wheel quill pinion rotates. This one is the one in the rack pinion shaft and will require apron disassy. This key will be the one if power feeding of carriage ALSO slips.

John
 
Is the spindle of the handwheel turning with the handwheel? If not you got lucky as it should be the easy key. My handwheel had a little slop and I snugged up the nut and that fixed that.
 
I'm pretty sure the spindle was turning, too. I'm a little worried about having to dig into the apron. I'll investigate it a little further. Has anyone on here gotten that far into the apron before? By no means am I an expert on these machines. I've never had to do any extensive work on a lathe before. Hopefully, I'll be able to figure it all out on my own, but I'm sure I'll be posting here in hopes of finding more advice and expertise.
 
I fully worked the apron in my High Duty machine which is the predecessor to yours, the apron shares a number of design features. The Pacemaker's is clearly more robust and modern- but you can work on it. You'll probabably have to take the carriage off the machine and detach the apron so you can start taking stuff apart from the back side of the apron.

You'll certainly need some kind of shop crane to handle the bigger items. The carriage will likely have to comeoff the end of the machine which means the tailstock end lead/feed/clutch supports will have to come off and the rods supported so they won't sag & risk bending.

Its a moderately big job, my lathe is a lightweight compared to yours and I covered two 4x8 work tables with parts while I worked through it. But if you like machinery, I think you'll love the job- ATW built nice machines.

Regards,

Greg
 
Between the holidays and cold weather, I haven't been able to spend much time working on my Pacemaker. Today, I did a little more investigation into the Z-axis slip. I noticed that the shaft driving the pinion gear (that traverses the carriage) stops turning when the carriage runs up against the stops. However, I can still turn the manual handle. The shaft on the manual handle turns along with the handle. So, from what I can tell, both of the said woodruff keys should be in tact. It makes me re-think what I said about a safety mechanism. Would there be a pressure slip system that would prevent one from manually crashing? It's the only thing I can think of. I haven't tried it under power as I still haven't even run this machine. I've been waiting to re-assemble the cross slide until I know whether or not I should worry about the carriage/apron. I also have to figure out why there is only a forward and stop switch for running it. It looks like it wasn't even wired to run in reverse. Any suggestions on these issues?
 
I can't really tell if this could have anything to do with your problem, but, you can adjust the apron clutch pressure on my PM by loosening set screws that position the "bells" on the front of the apron. Could it be as simple as a bump from a forklift shoved the bell in and now the clutch won't engage? I doubt it, but ???????
 
The last picture here;

http://www.lathes.co.uk/pacemaker/page5.html

shows the back-side of a Pacemaker apron. Looks very similar to my prev generation lathe. Assuming the designs are similar, there is no clutch between the carriage traverse wheel and the pinion. The power feed comes in from the bevel gear at the bottom of the pic, through the power feed clutch and onto the big gear thats mounted on the pinion shaft.

My guess is if the carriage traverse slips when the carriage hits a stop, then there could be a missing key inside someplace- I take it theres no sign of grinding which would suggest blown out teeth. I don't know how the gears are fixed to the shafts inside the apron, but I'm confident its somewhat different from my lathe.

I would guess against a manual feed safety. The power feed lever is supposed to act as a safety measure for that side of the powertrain but I don't think it is anticipated that an operator could endanger the apron powertrains by using the traverse wheel.

Regards,

Greg
 
Thanks again for all the info. The picture illustrating the back side of the apron really helped. Seeing that, I'm guessing that it is a key on either the gear at the backside of the manual handle or the larger gear that it drives. I'm not sure how easy it will be to access either. Hopefully, the problem will be in the smaller of the two (handle side). I'll have to see if I can get a view of what is and isn't turning while the carriage is stopped (and handle being rotated). Once I can see those two gears, I should know where the problem lies. It'll be tough to find the confidence to take the apron apart (if need be). Thanks to all for the help!
 








 
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