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New Bearings For Craftsman Drill Press Quandry

bmw57isetta

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Apr 27, 2010
Messages
268
Location
Austin, Texas
Howdy from Austin, Texas! I bought a late '50's Craftsman Model 150 floor standing drill press (103.24530) a few months ago and have dismantled the whole thing and rebuilt the press part of it. Thanks to all of you that have taken the time and effort to take pix of your C'Man DP projects, explain how you did it and post them here. They've all been a huge help! Might help to throw out kudos to a couple of folks over on owwm.net as well.

I've now started on the motor. a matching 1/2 hp Craftsman/Packard Electric model 115.19870. I started with the lower bell, cleaned it, painted it and pulled the lower bearing off. While the motor sounded smooth when you started it the bearing felt like it was full of gravel when out of the motor. 55 years worth of service and time to replace. Today, I bought two new 6202ZZ sealed roller bearings from the top bearing outfit in town. They're the same folks that supplied the upper and lower bearings for the front pulley shaft that fit like a glove. The original bearing I pulled out was an MRC 220 SFF-4 which crossed over the the 6202ZZ-5/8. This thing slides down the upper part of the shaft but just will not go over the slight taper to its final resting place. I put it in the freezer for an hour (worked like a champ on the pulley bearings) but no go. Heat gun didn't phase it either.

Using a digital micrometer (same one the vendor used) at home, I get the following measurements:

Original ID=.0627
New ID=.0623
Shaft OD=.0626

At face value, the math works for the old bearing but is that .0004 delta between the old and new the problemo or am I going to have to take this thing to someone with a hydraulic press? I don't recall reading about anyone that wasn't able to do this on their workbench.

Bottom line, did I get the wrong bearing? I've seen reference to a 6202ZZ-16 (mm). Is that the one I really need? Anyone done this without all the hassle and log the correct bearing number? Or is this just a wake up call to how it's done? If I've overlooked any pertinent info, please let me know.

You're input will be much appreciated ... Bruce Fullerton / Austin, Texas
 
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Alchymist

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Mar 1, 2009
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4,423
Location
Central PA
Is your decimal in the wrong place?

SB:
Original ID=0.627
New ID=0.623
Shaft OD= 0.626 ?

The bearing you referenced should have an ID of 0.6250. Something wrong with the measurements somewhere or a real poor bearing.
 
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bmw57isetta

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Apr 27, 2010
Messages
268
Location
Austin, Texas
Alchymist:

Next time I'll get a good nights sleep before I post a question. First of all, I had a case of decimalitis. I just took another set of measurements:

Shaft OD: .625
Old Bearing ID: .628
New Bearing ID: .623

Looks like that .002 delta between the shaft and new bearing ID is my problem. I don't think it's a bad bearing, I think it's the wrong one. For what it's worth, the OD on both old and new are 1.378.

Now I need to know if anyone knows the part number for the correct bearing. Should I run this on by the guys at Accurate Bearing and let them set me straight? Hope I got it right this time ... BF
 

larry_g

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Apr 28, 2007
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16,893
Location
oregon
If you plug 6202 bearing into your search engine you will find that the bearing specs out to be what you need. I know that measuring the ID of a bearing takes some skill and the correct tools, a caliper will not do it. The bearing you have should fit the 5/8" shaft. If it were me I would lightly polish the bearing area on the shaft to make sure there are no burrs or high spots on the shaft and then press it on. Bearings need to be a tight fit on the shaft. If they are not then the bearing will soon eat up the shaft as the shaft walks around in the bearing.

lg
no neat sig line
 

Provincial

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Sep 21, 2011
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6,874
Location
Near Salem, OR
Take the bearing back to the bearing supply along with the shaft. A good store should be able to determine the bore and shaft sizes with accuracy. The bearing could easily be undersized and slipped through QC.

I would make sure of the bearing before changing the size of the shaft, which, at .625 is exactly 5/8's of an inch. This is what you would expect for a US-built machine of that era. The bearing bore of .623 is much too small for that shaft size. That would give a press fit of .002, when it should be no more than .0005 (five ten-thousandth's of an inch), an really should be more like .0001.
 
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pacmktg

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Mar 1, 2009
Messages
297
Location
Foothills of CA
A 6202 bearing has a metric O.D and a Metric I.D. A 6202 -5/8 has the same metric O.D. And a special 5/8" I.D. The 6200 series of bearings are commonly known as electric motor bearings. Electric Motor shops use a bearing heater to heat up the bearing to make it slightly expand to slide over the shaft. They normally heat them to around 265 F. The 6202 bearing has a 15mm I.D x 35mm O.D.
 
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bmw57isetta

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Apr 27, 2010
Messages
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Location
Austin, Texas
Thanks for all of your input. That's what I need to know. Guess I got lucky on replacing the bearings on the front pulley shaft.
 

Dugbug46

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Apr 29, 2012
Messages
8
When I switched out the bearings on my Craftsman drill press, I set the bearings on a light bulb while the shaft was in the freezer. It worked out well for me.
 

1953mercury

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Nov 25, 2012
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701
Location
Steamboat Springs CO
should be a light press fit. if you don't have access to a press, I have installed them with a piece of pipe that sits on the inner race and a hammer. As recommended above a light cleanup of the shaft. Mike
 
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bmw57isetta

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Apr 27, 2010
Messages
268
Location
Austin, Texas
Dugbug46:

Nice tip about the light bulb! What I still need to know is if anyone has the brand/part number of the correct bearing they used. I can box everything up and take it to the local electric motor shop but I wanted to hear from some GJ'ers that have restored these Craftsman motors specifically which is why I started out here. I've read several threads on restos so I know it's been done, just no mention of specific replacement numbers.

Great info from all and much appreciated ... BF
 

Dugbug46

Member
Joined
Apr 29, 2012
Messages
8
I found this on the Vintage Machinery website.

115.19801 Craftsman 1/2 hp: original-MRC-202-SFF-4 (USA) 5/8 bore double shield; Accurate replacement-6202-5/8
It's a different model number, but the original bearing has the same ID number as yours.
Accurate is a company that sells bearings. It looks like you got the right bearing, so I don't know what to tell you other than maybe its just a bad one.
 
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