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theGallery
09-22-2016, 06:46 PM
I have an old 4" Powercraft jointer that I am restoring. It is in near perfect condition. The exception is the 1/2 ball bearing journal on the drive end of the cutter head. At some point the bear must have frozen and turned on the shift. The journal now measures .493. I am looking for suggestions to repair the problem. The drive shift is an internal part of the cutter head so I can not replace just the shift. I have several ideas but would like to hear from the experts.

MikeL46
09-22-2016, 06:50 PM
Can you turn the shaft down and install a Speedi-Sleeve?

http://www.skf.com/us/products/seals/industrial-seals/power-transmission-seals/wear-sleeves/skf-speedi-sleeve/index.html

Mike

10KPete
09-22-2016, 07:09 PM
I would look in to reducing the shaft diameter to the next size down bearing that has the same OD and thickness. I might be metric but......

If I recall correctly those machines were made by King-Seeley and are all inch size, so you may find a bearing with a slightly smaller ID.

Pete

Captain K
09-22-2016, 07:11 PM
Build it up with brass and turn down. Quick and dirty, maybe close enough, many small center punch marks around the surface, or lightly knurl.
turn down end and press on a sleeve. Never tried a speedi sleeve under a bearing, but they work great for seals

JoeLee
09-22-2016, 08:28 PM
Spray weld is great for shaft repair if you have the capabilities. Otherwise turn and sleeve.

JL...............

Andre3127
09-22-2016, 08:41 PM
many small center punch marks around the surface, or lightly knurl.

Punching and knurling are very bad ways to repair this shaft. For a few reasons.

Doozer
09-22-2016, 09:05 PM
Consider this idea...
I don't much like knurling either
but hear me out on this; The shaft
is likely pretty soft, so it will knurl
easily. Knurl the worn area, being
careful not to go overly deep.
After upsetting the steel, clean it
well and soft solder in the knurl.
This does not apply as much heat
as brazing, and no chance of warping
the shaft crooked. Turn the solder
and the knurl area back to size.
Remember, since it is a rotating shaft
was most likely a press fit, or .5005 inch.
The solder and knurl together make for
a more secure surface (not an engineering
term, but none the less), and I believe it
has a good chance of lasting as a repair.
If it does not work out, you can always try
something else, and it is not as invasive
as other repair methods, like brazing or
welding.

--Doozer

Andre3127
09-22-2016, 09:21 PM
Consider this idea...
I don't much like knurling either
but hear me out on this; The shaft
is likely pretty soft, so it will knurl
easily. Knurl the worn area, being
careful not to go overly deep.
After upsetting the steel, clean it
well and soft solder in the knurl.
This does not apply as much heat
as brazing, and no chance of warping
the shaft crooked. Turn the solder
and the knurl area back to size.
Remember, since it is a rotating shaft
was most likely a press fit, or .5005 inch.
The solder and knurl together make for
a more secure surface (not an engineering
term, but none the less), and I believe it
has a good chance of lasting as a repair.
If it does not work out, you can always try
something else, and it is not as invasive
as other repair methods, like brazing or
welding.

--Doozer

A silver solder should work well. Lead solder would probably be too soft.

If only using knurling alone, it probably won't last long because there is so little in contact with the bearing, and radial forces (from the hammering forces of cutting wood) will mush the knurls back flat with the shaft in not much time. Plus, who knows if the bearing will sit on the knurls accurately.

Tim Clarke
09-22-2016, 10:15 PM
So, during my time as a heavy-duty truck mechanic, I rebuilt some drive axles, rear ends, butt gears, or whatever you would call them. Many times I would find that the carrier bearing(s) had spun, and had worn the bearing journal, or whatever you would call it, with the loss of the press fit. Almost always on the thrust side. So, a light knurl would be applied. Lock-tite was slobbered on and the bearing was pressed home. Usually, there was also wear on the thrust face, but it was no big deal since the adjusting nuts allowed the proper backlash to be established. Since I worked for a private fleet, All the work I did came home to me every night. I guess the point is, I never had one come back with the knurl/Loctite fix failed.

TC

Andre3127
09-22-2016, 10:22 PM
So, during my time as a heavy-duty truck mechanic, I rebuilt some drive axles, rear ends, butt gears, or whatever you would call them. Many times I would find that the carrier bearing(s) had spun, and had worn the bearing journal, or whatever you would call it, with the loss of the press fit. Almost always on the thrust side. So, a light knurl would be applied. Lock-tite was slobbered on and the bearing was pressed home. Usually, there was also wear on the thrust face, but it was no big deal since the adjusting nuts allowed the proper backlash to be established. Since I worked for a private fleet, All the work I did came home to me every night. I guess the point is, I never had one come back with the knurl/Loctite fix failed.

TC

I'm glad that everything worked out for you. I have not had such good luck with press fits on knurled items, they always tend to loosen. If OP can do a more professional repair by turning and sleeving, I think that is the best way to go about this.

theGallery
09-22-2016, 10:33 PM
One of the ideas I was exploring.
1) light knurl on the bearing journal.
2) turn the journal to fit the bearing. The bearing should now be near original fit spec.
3) Loctite in place.

Thoughts.

Tim Clarke
09-22-2016, 10:56 PM
I'm glad that everything worked out for you. I have not had such good luck with press fits on knurled items, they always tend to loosen. If OP can do a more professional repair by turning and sleeving, I think that is the best way to go about this.

Oh, ya I agree, the first class fix is always the best!

Regards, TC

theGallery
09-22-2016, 11:16 PM
Since the shift size is only .5" I am concerned about weakening the drive end of the cutter head by turning it down and installing a sleeve. Are my concerns justified?

Andre3127
09-23-2016, 12:18 AM
Since the shift size is only .5" I am concerned about weakening the drive end of the cutter head by turning it down and installing a sleeve. Are my concerns justified?
Remember the sleeve would be a tight fit, or held on with loctite or silver solder. Since the forces are almost all radial on a jointer cutterhead, you should be okay in my opinion.

Sent from my XT1053 using Tapatalk

Mcgyver
09-23-2016, 11:26 AM
turn between centres and take off enough to clean it up. loctite on with close fit a sleeve. turn it to .500. sharp tool, light cuts and coolant - its a very thin walled sleeve. Done.

You want to maintain concentrically and minimize material removal to keep it as close to as strong as it was intended.

You could part it off, drill into the head, press fit a length of chrome moly and turn it down to .500"....but imo that isn't necessary if you're only taking off a small amount.

I also like the bearing idea.....12mm is .472 which would work well

cameron
09-23-2016, 01:30 PM
turn between centres and take off enough to clean it up. loctite on with close fit a sleeve. turn it to .500. sharp tool, light cuts and coolant - its a very thin walled sleeve. Done.

You want to maintain concentrically and minimize material removal to keep it as close to as strong as it was intended.

You could part it off, drill into the head, press fit a length of chrome moly and turn it down to .500"....but imo that isn't necessary if you're only taking off a small amount.

I also like the bearing idea.....12mm is .472 which would work well

Assuming the original bearing is not one of the bastard sizes with inch bore and metric OD, the 12mm bearing will not fit the housing, so it would entail fixing two problems rather than one.

Arcane
09-23-2016, 01:57 PM
turn between centres and take off enough to clean it up. loctite on with close fit a sleeve. turn it to .500. sharp tool, light cuts and coolant - its a very thin walled sleeve. Done.

You want to maintain concentrically and minimize material removal to keep it as close to as strong as it was intended.
.........

I agree. A full length sleeve would eliminate having to futz with the pulley on the drive end and you wouldn't have to search for a different bearing.

Magicniner
09-23-2016, 02:23 PM
I'm glad that everything worked out for you. I have not had such good luck with press fits on knurled items, they always tend to loosen. If OP can do a more professional repair by turning and sleeving, I think that is the best way to go about this.

Sleeving is preferable but getting someone to show you how to knurl and use a bearing fit compound is also an option, it works fine if correctly executed!

- Nick