sears jointer 149.21871 bearings

[Karl Wicklund]

I've got a 4-1/8" jointer, branded Sears, made by AMT. Probably early 80s.

The bearing were shot, and I was able to pull them well enough, but I don't know enough to buy replacements. I figured there would be a number on the bearing itself, but they are totally without markings. (Oddly there is also no serial number for the machine itself. The model number is stamped on the plate, but the serial space is blank.)

The bearings are sealed, 1/2" I.D., 1-1/8" O.D.

I've tracked down an owner's manual, but it doesn't have those specs.

Sears and other replacement sellers list the part as "no longer available" but that must just mean the machine is no longer serviced. It seems like it must be a standard ball bearing.

Do I need anything very special on this little machine?

[Richard Coers]

AMT would not have used a custom sized bearing. Any online or local bearing store has a replacement for you.

[Karl Wicklund]

Thank you Richard. I assumed as much, but I'm only just dipping my hand into servicing my stuff.

[Bill Dufour]

Measure them with metric calipers. Very unlikely they would be English size. A harbor freight digital caliper is good enough. Check the rubber seal very carefully for a number cast into the rubber under the gunk. You are looking for a 4

[Karl Wicklund]

I checked with calipers, but I'll check again. What makes you suspect metric on this machine?

[Jerry Bruette]

I checked with calipers, but I'll check again. What makes you suspect metric on this machine?

Metric on most every machine. That's the way bearings are made, most are metric only the oddballs are standard.

[Dave Sabo]

While I agree the bearings in question are prob. metric sized; Sears was known for sourcing oddball stuff. Could be argued that 4 1/8” is an oddball size in and of itself.

[Ronald Blue]

They don't have to be metric. Given the age of the machine and all. If Karl already measured with calipers I don't think he's that far off.

https://www.mcmaster.com/ball-bearings/for-shaft-diameter~1-2/permanently-lubricated-ball-bearings/

[Bill Dufour]

If a machine is newer then about 1930 I would assume metric unless it is farm equipment. I can not see AMT paying extra for English size bearings. Very often the shaft will be English with a raised metric boss at each end the bearing sits on.
Make sure the replacements are sealed not shielded.
Bill D

[Ronald Blue]

If a machine is newer then about 1930 I would assume metric unless it is farm equipment. I can not see AMT paying extra for English size bearings. Very often the shaft will be English with a raised metric boss at each end the bearing sits on.
Make sure the replacements are sealed not shielded.
Bill D

I'm not assuming anything. Here's a metric 6000 series bearing dimension chart. The only thing close to his stated ID is nowhere close to his OD dimension. I only went that direction because I presume he can read calipers. Despite the apparent age reference you can find it on Vintage Machinery and it looks more like a 50's design.

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fcnc-specialty-store.com%2Fimages%2Fbearing%2F6200table.jpg&f=1&nofb=1

[Dave Sabo]

Another thing y’all might consider is that AMT was an importer more than a manufacture. And their factory was in Taiwan.

Think it was sourcing/using non metric size bearings ?

[John Gustafson]

Back in the day when New Departure ruled the ball bearing world there was an "R" series of deep groove ball bearings that were made to imperial dimensions so the inch dimension is a distinct possibility. What you describe could be an R8 bearing. The width is 1/4" if its open or 5/16 with shields or seals. McMaster-Carr lists them as a starting place.

[Dwight Rutherford]

Check with VXB they should be able to help.

https://www.vxb.com/default.asp

[Karl Wicklund]

Thanks guys.
I and my kids checked the bearings in strong light. No markings.
I double checked and it's 1.125" OD, 0.500" ID on my (admittedly cheap) dial caliper. 0.31" width.
I'll check in with McMaster Carr.

[Austin Grote]

Find a bearing supply house in your area, if you bring them the bearing they will measure it and provide you with the correct bearings.

This is a very common practice.

[Stan Coryell]

McMaster has them. 1/2 and 5/8 ID aren't odd sizes.

Bearings, Sealed, Trade Number R8-2RS, for 1/2" Shaft Diameter

https://www.mcmaster.com/60355K704

[Karl Wicklund]

I appreciate the suggestions, but the nearest bearing supply house is an hour away, and not in a direction I usually travel.

[Brian Runau]

Sounds like you may have an R8 series bearing. Not sure the width you need. R8 is the common size number for it.

https://www.astbearings.com/catalog/precision_r_series

Brian (https://www.astbearings.com/catalog/precision_r_series)

[Austin Grote]

Call the bearing house, maybe you can just send them the bearings, measure them and provide you with the replacements.

[Ronald Blue]

If he ordered from Mcmaster Carr he already has the bearings. It's highly unusual to order from them and not have it the next day. Most bearing houses don't carry anything unusual these days unless they have regular demand for it. No reason to make it difficult when there is a simple solution.

[Karl Wicklund]

1/2" x 1-1/8" x 5/8" bearings arrived. They are identical, but with the expected lettering on the seal. Thank you all for the help. Now I hope this little guy can get back to work.

[Austin Grote]

No reason to make it difficult when there is a simple solution.

Thank you for critiquing my suggestion. I will try to do better next time.

[Ronald Blue]

Thank you for critiquing my suggestion. I will try to do better next time.

Are we overly sensitive? I DID not quote your reply. You also weren't the only person to tell him to go to a bearing house which he had already addressed. Maybe you didn't read the whole thread. That's something that seems common these days. If I offended you I apologize. Be happy he received the bearings and can put it back together. Have a good day.