[4]

Replacing the broken bearings in my pm1440gs headstock

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
There are 5 shafts in the headstock of a pm1440gs gearhead lathe. I have the misfortune of having one that is eating its bearings. On shaft B as labeled on page #39 in the manual, I isolated all the shafts so you could turn each of the shafts independently. Using a stethoscope I was able to turn each shaft and listen for clunking. On removing the plates covering shaft B from the left side as you look at the lathe headstock on your left. I got a nice pile of metal shavings, and that specific shaft does not spin freely as the others do...
PM says just use a slap hammer and pull the bearings out that way.... I am confused, I see a m6x1.0 thread in the end of the shaft. Is the intent I thread a screw into the shaft and use the shaft to pull the bearing out? I see no other way to remove the bearing.

Any help greatly appreciated

20190601_173848.jpg20190601_173832.jpg20190601_173828.jpg20190601_173845.jpg
 

Cadillac

Brass
Registered
Joined
Mar 12, 2018
Messages
919
On the chuck side of headstock I would guess those are covers with a Oring groove. The picture of the inside of headstock looks like the bearings bottom out to a flange on housing so they must go outward. I would probably use a brass punch for removal. Looking at pic again looks like outboard bearing would come out first using shaft to drive out. Then chuck side. Outboard pic of bearing and shaft its looks like a center in shaft not threads? If it is threads yes a slide hammer can be very helpful. Good luck
 

Z2V

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
May 10, 2017
Messages
755
I took my PM1236 apart tonight. It’s not the same gearbox but the shaft in your third pic looks very similar to mine. I pulled the belt pulley off and used a punch to push the shaft out from the chuck side toward the left. The bearing in pic three stayed on the shaft, naturally, and the bearing beside the chuck stayed in place in the housing. Probably not much help for you but that’s what I worked on this evening. Is your problem on the belt side or the chuck side of the shaft? If I’m reading you correctly it’s pic three.
 

Firstgear

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Dec 7, 2018
Messages
451
I have a 1440 GS, since about January of this year. Minimal hours running it. When did you get yours and how many hours do you think you have had it?

I previously pulled the top cover off and everything looked clean.
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
I got mine 1st week in August 2017. Hours of use, probably around 20-30 hours. It looks bad because I coated it with wd40 this past winter to keep her from rusting
If you are hearing clunking in the gear head the bearings in the pulley shaft or the shaft just above it are just cheap chinese bearings. I've had noise and vibrations issues with the machine since I got her.

That "best in the industry, 3 year warranty " you should read it sometime :rolleyes:
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
I took my PM1236 apart tonight. It’s not the same gearbox but the shaft in your third pic looks very similar to mine. I pulled the belt pulley off and used a punch to push the shaft out from the chuck side toward the left. The bearing in pic three stayed on the shaft, naturally, and the bearing beside the chuck stayed in place in the housing. Probably not much help for you but that’s what I worked on this evening. Is your problem on the belt side or the chuck side of the shaft? If I’m reading you correctly it’s pic three.
Thanks for taking the time to stop by and post. To answer your questions, I cant say for sure right now but it might just be the belt side. I plan on replacing both bearings. The belt side had a nice pile of metal shavings when I pulled the cover/flange off to expose the bearing. As Cadillac pointed, both bearings slide in from the outside of the case. There is almost no room to remove them from the inside, there are gears obstructing access on each side.

I'll make a harbor freight run this morning and pick up a slap hammer. I'm being extra cautious with this, not my typical dive in and get dirty approach.
 
  • Like
Reactions: Z2V

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Looking at picture #3, all the black dust, u guessed it, that was from my bearing grinding itself up. I used to look in when I pulled the cover, it always looked dirty, I figured it was from the pulley belts. Now I know. Hopefully this gets this machine running much better...
 

Ulma Doctor

Infinitely Curious
H-M Supporter - Gold Member ($25)
Joined
Feb 2, 2013
Messages
383
the black dust may have been from the brake linings (lower left picture 3)
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Possibly some, agree I had overlooked it. The shaving were metal though.

Ok, keeping my positive attitude
Plan A does not seem to be working. Taking some points from z2v. I am working on plate on the chuck side. I threaded in a m6x1.0 socket cap screw, nut and washer.20190602_112328.jpg
I modified a mount for the bearing puller hammer
20190602_112240.jpg
20190601_173848.jpg
It is not moving, I scrapped around the cover remo20190602_112300.jpgving any material, paint, bonds, gasket sealer... whatever.
Anyone want to guess on how this cover comes out? Thread, pressed in, magic. She is in tight.
 

Cadillac

Brass
Registered
Joined
Mar 12, 2018
Messages
919
What Does the parts breakdown show that threaded part as a cover? I would imagine so because it looks the same od as the bearing from the inside pic. Cannot be shaft their would be no room for bearing.
With a slide hammer you will want to thread the end of hammer to the threaded cover. Any loss of motion is bad. Soak the cover with some pb blaster or your preference. Maybe a shot of co2 or air duster to try and freeze cap to shrink? Good luck
 

Cadillac

Brass
Registered
Joined
Mar 12, 2018
Messages
919
I took a look at my manual and it shows those as caps with a oring.
image.jpg
I’m guessing they weren’t lubed in the installation plus coated with paint after Assy they will probably be a bear to get moving. Spray them down with some penetrating fluid.
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Thanks Cadillac. Yea that's what I've been looking at the past couple days lol. Pm glossed over it as if a trivial detail when I asked for a procedure. I have, tapped, bumped, cleaned the edges, screwed the cap screw in all the way to bottom it out and hope exert pressure from inside... placed a 10lbs barbell weight on the slide of the bearing puller... I'll try the co2 next. Liquid wrench is soaking...
Thanks for the help. Its keeping me in the right frame of mind and on focus on how to approach this.

WARNING!!! Chinese machines are wonderful bargains, and good machines if you get a good one, else they are full time parts kits lol
 

mattthemuppet2

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Sep 28, 2013
Messages
1,816
another approach to pulling that cover out - make a ring with an ID a little larger than the cover. Cut it to fit next around the spindle. Get a piece of plate with at least the same OD as the ring and nice'n'thick. Drill a hole in it large enough to fit the screw through. Assemble it over the cover, thread a long enough bolt through with a couple of copper washers under the head. Tighten down as much as you dare, then leave it over night. Maybe play a MAP torch around the outside of the ring for a bit, maybe on the bolt itself. Tighten it a bit more, then leave it. If you strip the threads on the cover, drill it out and tap it to the next size.

If none of that works then at some point you're simply going to have to cut/ chisel the thing out and make a replacement. Annoying but not particularly difficult. Good luck!
 

Cadillac

Brass
Registered
Joined
Mar 12, 2018
Messages
919
I guess this is where a pressure lubed headstock is better. Guaranteed lubed instead of the splash/drip system we have and would help to flush contaminate out of crucial areas.
 

wrmiller

Chief Tinkerer
H-M Supporter - Gold Member ($25)
Joined
Mar 21, 2013
Messages
3,549
I guess this is where a pressure lubed headstock is better. Guaranteed lubed instead of the splash/drip system we have and would help to flush contaminate out of crucial areas.
Until the pump quits and you don't catch on until it's too late! :eek:

I've had my share of Chinese 'kits', and managed to make some work really well and others not so much. Best of luck with this @richl.
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Think I'm making a 2000lbs piece of scrap. This is not going well at all. Going to stop for the night. Frustration level high. Maybe try and weld a clip to it tomorrow.20190602_200810.jpg
 

john.k

Active Member
Registered
Joined
Nov 4, 2018
Messages
204
"Broken bearings " in 30 hrs............Id like to see that...................Unfortunately beginner diagnosis is not reliable,and a perfectly good bearing will often make some noise due to particles in the oil.......and regrettably Chinese lathes do have plenty of particles in the oil........however its either sand or cast iron swarf,and neither will seriously damage hard steel rolling elements..........Please dont break everything to pieces with amateur efforts to remove one $5 ball bearing.
 

Firstgear

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Dec 7, 2018
Messages
451
If that was me, I would thread a few of those holes and and use some bolts to pull that sucker out.
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Bearing is right behind it, not able to run a tap.
Thanks for those kind supportive words john k.
The bearings were toasted. Whether you believe it or not does not matter to me.
 

Cadillac

Brass
Registered
Joined
Mar 12, 2018
Messages
919
Looks like you’ve given a good effort that’s for sure. Maybe try to spin the cover by using a punch and just try to get it to budge. Has it moved any? Looks like it’s moved in if anything? I would probably stay away from a torch.
What happen with the center hole? It might be best to make a puller like suggested above with a larger id so you can apply constant pressure on cap by backing out the screw threaded in the center. That center hole will be your best best applying equal force.
Soak it overnight give it your best tomorrow you will get it. Best of luck
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Thanks Cadillac. Screw in center hole finally broke. I dont want to drill in that area because the shaft is right behind it. Did the center punch thing. Cant get the plate to travel out. Going to try a couple more things tomorrow. I decided to stop before the frustration level got too high. Probably try tapping holes on opposing sides and use a different pulling method. The bearing puller was not enough.
I've done more stubborn jobs, wish it weren't my lathe though. No amount of effort will make it turn in the opening. Tomorrow is another day.
 

mikey

Active User
H-M Platinum Supporter ($50)
Joined
Dec 20, 2012
Messages
5,464
Hey Rich, you have an essentially new lathe that is still under warranty. It seems to me that PM would be able to walk you through this process instead of having you guess or damage something. I think I would call to speak to a tech and have them explain the disassembly process in detail instead of trying it on your own. If you damage the lathe then its on you; if they gave you a specific procedure to follow and you damage the lathe doing that then its on them. Sorry you're having issues but even sorrier that PM is not giving you the support you deserve.
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
A few people here have made assumptions that are not correct. A spoke to pm and texted them and had conversations. Read the " best in industry 3 year warranty" they offer no more than parts, at there discretion. I asked about a procedure to follow for fixing this, they had nothing. I put this info in a previous message.
I went to my last resort, here. I have made some errors, the screw breaking off in the plate. Now it's my problem. I'll deal with it.
Thanks for the support, and help. I'll deal with this myself.
 

BenW

Active Member
Registered
Joined
Feb 24, 2018
Messages
72
Drill holes in a line then use a die grinder to split the cover in 2/3 pieces? Or do you intend to try to save the cover?

Sent from my LYA-L29 using Tapatalk
 

Firstgear

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Dec 7, 2018
Messages
451
Looking at post 9 and 13, it seems you did move it, but it’s now in the hole unevenly. Look at the photos and the bottom of the disc is in further than it was at the start. I would be tempted to tap that top in and get the disc even.

Remove that broken bolt.

Buy a grade 8 or better bolt to go in the hole, but before you put the bolt in, put a circular disc that is larger than the the disc you are trying to get out. Make sure you have tapped four evenly spaced holes around the perimeter of the new disc. You will use these as jack screws to evenly pull that disc out. If it is cocked liked it is now you will play hell trying to get it out.
 
Last edited:

Firstgear

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Dec 7, 2018
Messages
451
The nice thing about jack screws is that you can evenly pull that sucker out. Screwing each one just a bit at a time will get that disc to pull out very evenly......
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Firstgear, I appreciate the input. We are well beyond the tapping and pulling method lol sorry. The plate is only out of stew by a couple thousandths. I was taking regular measurements all throughout the pulling process.
This plate is at least 3/8" thick. That I am thankful for, I thought I might have gouged the shaft, making this repair a living nightmare.
Benws post is closer to what I am doing, carbide bit in a die grinder and slowly just milling the plug out, most of the milling is down around .28". I still left enough on the sides so I am not gauging the opening. It will take some time, but eventually it will be thin enough to pull out.

I get it that everyone's first impression of me and what I am doing is I'm a hack. I tried to go into this thing with all the info I needed, I asked a few people that had done similiar on other gearhead lathes, I asked the distributor for the machine and I asked here. If I had known the plate was in the 3/8" thick area, I would have approached this differently.

I thank those that have offered me honest well intended advice and encouragement, and for those who enjoy kicking a man when he is down, I have no opinion to express for you.
 

Firstgear

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Dec 7, 2018
Messages
451
I have had my challenges just like you are having....I usually walk away thinking about it for a day or two when I am not so frustrated, then I come back to tackle the job. I had a very frustrating experience putting together a 1960 Corvette top. I had found a way to slip my screwdriver not once, but twice onto the back plexiglass window. I needed up becoming very good at fixing that, but I often come in the house when frustration is running high....I think better once the frustration has subsided.

You will overcome this, just take a deep breath and walk away when needed.....
 

richl

Active User
Registered
Joined
Mar 2, 2013
Messages
894
Ok. That is out. Not too sure I gained anything.
I am prepared to just send her to the scrap yard.
Anyone have any ideas how these bearings come out?20190603_142426.jpg
20190603_142409.jpg
20190603_142358.jpg
 

Attachments

TakeDeadAim

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Apr 17, 2015
Messages
282
Please hang on a bit, Ive done machine repair for many years. Lots of machines, lathes in particular are assembled this way. I can help you with this but I need an hour or so to wrap something up. If you want to PM me a phone number where I can call you I would be happy to do that when I am done.
 
[5] [7]
Top