overhaul on Porper lathe

C

carguy

AzB Silver Member
Silver Member
My Porper B was somewhat loose and tired when I got it around 8 years ago and has not improved since then, so I am finally going to do some maintenance and upgrades, including new spindle bearings.
It looks like a pretty straight-ahead job, but I can't get the chuck adaptors off either end of the spindle.
I presume they were a shrink fit when first installed because they are really on there.
I have quite an arsenal of pullers, but nothing suitable.

And yes, I have loosened the setscrews.:smile:

Has anyone done this job? Does anyone have a good idea?

Robin Snyder
 
When I did mine it was the same thing.

I closed off either end of the spindle with a towel and packed it with ice,
shrunk it just enough for the gear puller.



Paul
<@>
 
The problem with heating the adaptors (I tried it) is that the spindle is a big heat sink, too big for the Prestolite torch I have here. If I had an oxy/acetylene here I could get it pretty hot, but everything else would too.

Packing the spindle with ice is a great idea and I'll try that next.

One big problem is that once you get one end apart you have nothing to push against with the puller screw to do the other end.
So Paul, what did you push against?
Robin Snyder
 
Last edited:
Hey Robin,

After I removed the front chuck adapter (I have a chuck on both ends)
I made a plug for the spindle out of aluminum 1.490" to slip fit the ID, and 1.700" to be .075 under the OD.
Then I used the tail stock and a 1.500" tube of Phenolic to push it
an inch or two at a time.

DO NOT FORCE IT!!!!!

Once you get it loose and have no room left to use the gear puller
move to the plug and tail-stock.

Remember the tail-stock is NOT designed to be used as a press,
so make sure the spindle is free first and you shouldn't have any problems

Also, make sure you don't have any scoring on the spindle from the chuck adapter BEFORE
it slips into the first bearing, otherwise you'll be cutting the bearing off the spindle.


Good Luck and keep us informed of your progress,
Paul
<@>
 
Last edited:
Outstanding info, just what I wanted. Thanks!!

Check out the motor swap I described in my post in Machinery and Supplies.

Robin Snyder
 
Last edited:
So someone got there before me. The "nut" for the tailstock is a press fit in it's hole, but once upon a time it came loose. The fit was restored with a center punch and red loctite, so I might as well fix this while I'm at it. I'll use a bottle jack, gently, to do the pushing for the spindle bearing job..
It's always something...no big deal.

Robin Snyder
 
I drove the spindle through the pass thru with a square block of maple and a hammer. u will probably need some red locktite if the spindle was scored. place the removed spindle in the freezer overnite. replace your spindle bearings and put the red locktite on your spindle as you pass the frozen spindle thru your bearings. let the locktite set overnite before u run the lathe or you will throw it out from the rpms. I did not remove the headstock when I knocked the spindle thru the passthru. put the red locktite all around the spindle as you pass it thru the bearing, that way the locktite will fill your scoring. when I was done I was 1/2 thousands on front headstock and a 1/4 thousands on my rear headstock. hope this healps. U can call john at creative inventions and he would be helpful also.
 
bob_bushka said:
I drove the spindle through the pass thru with a square block of maple and a hammer. u will probably need some red locktite if the spindle was scored. place the removed spindle in the freezer overnite. replace your spindle bearings and put the red locktite on your spindle as you pass the frozen spindle thru your bearings. let the locktite set overnite before u run the lathe or you will throw it out from the rpms. I did not remove the headstock when I knocked the spindle thru the passthru. put the red locktite all around the spindle as you pass it thru the bearing, that way the locktite will fill your scoring. when I was done I was 1/2 thousands on front headstock and a 1/4 thousands on my rear headstock. hope this healps. U can call john at creative inventions and he would be helpful also.
Click to expand...

This sounds like a workable procedure.
If my spindle is badly scored I'll probably replace it. They are not that costly straight from Creative Inventions.
I think I'll skip the red Loctite too. I might want to dis-assemble it some day.

But now I'm delayed by work I have to do, and I want to have a new spindle pulley I'm making for it ready when I tear it apart. I'm thinking about fitting a different front chuck at this time also but I have to finish the adapter I started for it a couple years ago.

All this work plus my new extra huge motor....this will be fun!

Robin Snyder
 
Use the red Loctite!Or down the road the spindle will move within the bearings and then you'll be ripping it apart to use red Loctite.
 
str8shooter said:
Use the red Loctite!Or down the road the spindle will move within the bearings and then you'll be ripping it apart to use red Loctite.
Click to expand...

Well, I disagree. The assembly should not need any loctite to be just fine if the fit is correct.

What would be your plan for disassembly?

It's OK for certain things, like like light press fits or push fits you never want to take apart again. If you use red loctite it will not be coming apart.
The shear strength of those assemblies is very high and won't press back apart without some very serious force.
It would be useful if I had, for example, a shaft which a bearing had spun on and I could not get a new shaft and could not readily make one. If I made a repair like that though, I would expect to do some damage on disassembly. It's made for permanent assembly.
.

I have a bit over 50 years experience with the stuff,

Robin Snyder
 
photos

ratcues said:
Post some pics if you get a chance. I'm interested...
Click to expand...

OK, a few people want to see this. I know I'm lazy to the bone about this, but Randy told me how to do it years ago.
I'll see what I can do.

Robin Snyder
 
So here's a wild and crazy idea I thought I'd pitch out here.

It seems as though I could pretty easily convert the machine to tapered roller bearings while I'm at it...I presume the originals are ball bearings, right?

I could make a spacer tube to separate the inner races and use shims to set preload, which I would have to make, probably the biggest pita of the job.

But then it would have zero radial and axial play!!!!!!

I wonder if appropriate bearings are available?

Or am I just trying to put too sharp a point on the whole thing?

Just an idea.

Opinions?

Robin Snyder
 
Here is a pic...

0709131430.jpg
 
Thanks for posting this for me Ryan.

Edit: This refers to my thread New Power for Old Porpers in the Machinery section so I've deleted it here and moved it over there.
I'll try to stick to my spindle bearing project here.



Robin Snyder
 
Last edited:
Another great idea down the tube...

carguy said:
So here's a wild and crazy idea I thought I'd pitch out here.

It seems as though I could pretty easily convert the machine to tapered roller bearings while I'm at it...I presume the originals are ball bearings, right?

I could make a spacer tube to separate the inner races and use shims to set preload, which I would have to make, probably the biggest pita of the job.

But then it would have zero radial and axial play!!!!!!

I wonder if appropriate bearings are available?

Or am I just trying to put too sharp a point on the whole thing?

Just an idea.

Opinions?

Robin Snyder
Click to expand...

So here's why this won't work (easily) :

The plates the spindle bearings are supported in are not tied together very well, in fact, the original metal tray top for the headstock looks like it's structural, and I should probably lose that Delrin top I made and make a steel or heavy aluminum one. So there's not much for the preload on the bearings to push against. Oh well, standard bearings then. No time wasted, just another thing I know not to do.

Robin Snyder
 
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