04-07-2021, 12:33 PM (This post was last modified: 04-10-2021, 10:28 AM by Philip1231.)
So I disassembled the motor on the Delta DP I am currently refurbishing. The bearings seem OK, but I thought I would try to replace them just for fun (and to learn how). The bearings on both ends of the rotor are marked: MRC 203.
Is there some way to cross reference this to a modern day bearing? I assume these are at least 50 years old, and the bearings I keep finding are sized in metric: confusing. Any help would be appreciated. Thanks
(04-07-2021, 12:57 PM)Kudzu Wrote: Yes. Just paste MRC 203 bearing into google and lots of them will pop up.
Bearings don't change much over the years.
Well, I did try that, and the first thing I noticed is that Amazon has only one of these listed, and its used. That was a red flag for me. So, for example, when I search for MRC 203 SFF, I get 6203 returned in the search. How does a 6203 relate to a 203?
Do I need the SFF, or is some other suffix preferable. Does it have to be an MRC or is that simply the mfg. and not necessarily descriptive of the type of bearing?
OK: bumbling along into the unknown (quoting another WW on another forum): bearings are not so simple. I came across a cross-reference for the MRC 203 SFF bearing: among others, a NSK 6203 zz: available on Amazon for $17.80 each. Here is link:
04-07-2021, 11:57 PM (This post was last modified: 04-07-2021, 11:58 PM by lift mechanic.)
I am no expert but have replaced thousands of bearings. The bearing that is pictured is a shielded bearing. The 203 is the same as 6203. There is a difference between shielded and sealed bearings. A sealed bearing will be marked 6203 2RS. I have seen shielded bearings marked with XXXX ZZ which if I remember correctly is the shielded bearing. Hope this helps.
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I'd like to pull the trigger on this: would someone confirm that this is indeed the bearing I need to replace the original MRC 203 SFF? Thanks Much!
Measure the old bearing. As someone said, they haven't changed much over the century. There are inch series bearings, but metric are way, waaay more common, and you'll know if it's right instantly with a couple of caliper measurements. ID (d), OD (D), and inner and outer race width (B).
Oh, and two shields would be fine for a motor. It's essentially a labyrinth seal, with no contact, unlike lip seals, but they'll keep the grease in and the dirt out just fine.
Here's a scan from my NSK catalog from 1989. Yeah, it's old, but no, they haven't changed in a very long time. Sorry for the big black streaks, but my scanner doesn't like when the paper is off the platen.
Tom
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Accuratebearing.com is a good source of quality bearings, even quite unusual ones to fit older machines. Many people at OWWM.org (Old Wood Working Machines) have refurbished machines using bearings from accurate. They have a good website where you can request a quote, and someone will call you back to make sure you've got the right thing, or you can call and ask for Jennifer. Just keep in mind that they are trying to help out and not making much from the transaction, so make sure to have all measurements at your fingertips.
Very likely that bearing is a plain old 6203 size.
17mm bore, 12mm thick, and 40 mm outside diameter.
6203LL = two rubber seals (preferable for woodworking appllication)
6203ZZ = two metal shields
Lots of places have the 6203 size bearings, even hardware stores. The 'gotcha' detail is that there are some very awful 6203 bearings out there.
An electric motor repair shop would be a good local place to go to when asking for a well made bearing.
04-08-2021, 10:43 PM (This post was last modified: 04-08-2021, 10:45 PM by Cian.)
(04-08-2021, 10:41 AM)Alan S Wrote: Accuratebearing.com is a good source of quality bearings, even quite unusual ones to fit older machines. Many people at OWWM.org (Old Wood Working Machines) have refurbished machines using bearings from accurate. They have a good website where you can request a quote, and someone will call you back to make sure you've got the right thing, or you can call and ask for Jennifer. Just keep in mind that they are trying to help out and not making much from the transaction, so make sure to have all measurements at your fingertips.
More details are on the OWWM site.
What Alan said. Very helpful folks. When I upgraded the cutterhead on my jointer, I walked in with the old bearings and new cutterhead and the tech read the markings on the old bearings, mic'ed the spindle on the new cutterhead, then went out back and brought out exactly what I needed.
I bet if you call them or at least email them pics of your bearings and application, they'll know and likely have exactly what you need.
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