Visual wobble of saw blade

[awatson6]

Good morning all. I recently purchased a Mark V, model 500 (1982). After a thorough lubrication and cleaning; I noticed a visual wobble to the saw blade as it started up. I switched to a new sanding disk I already had and it too wobbles. In fact, while holding a 1 x 2 to the disk, I can feel that the disk is not running true. I removed the disk and grabbed the end of the spindle and there is a noticeable amount of play in the spindle. What trouble shooting tasks should I perform to determine the necessary repairs?

Thanks in advance.

[wa2crk]

Noticeable play in the quill is an indication of a possible bad bearing in the quill. If it is a single bearing quill then the nylon coupler could be a problem.
Dis assembly and a thorough inspection is necessary I believe.
Bill V

[awatson6]

I do believe it is a single bearing. Tell me more about this nylon coupler. I have not read about this before.

[wa2crk]

There is a nylon coupler that connects the splined end of the quill to the drive shaft. The drive shaft is the shaft that is turned by the poly V drive belt. It is there to absorb extreme stress from binding or a jam of the blade.
I have never seen one fail in about 30 years so Iwill put my money on the quill bearing. Please do not use the machine until the blade wobble is corrected. Doing so may result in a kickback.
Bill V

[JPG]

The quill shaft is long and splined inside the quill. That splined shaft runs through a nylon coupler attached to the upper(main) shaft. The splines are what allows extending the quill with power applied at any extended position(up to 4 1/4"). The splined shaft slides in/out of the coupler center which has mating splines to allow the rotation of the upper shaft to be transmitted to the splined quill shaft.

With the older single bearing quills, there is always some some play in the bearing which becomes very obvious at the far end of the splined shaft. It is so pronounced that a spacer is inside the far end of the quill to center the far end of the quill shaft for inserting the quill shaft into the coupler when placing the quill into the headstock.

Thus the coupler also acts similar to a second bearing by limiting the end play of the far end at the coupler.

As just said, the couplers are not known to wear/fail.

The older single bearing is relatively easy to replace.

The bearing of choice is a fafnir, but they are $$$$

The bearing size is somewhat unusual in that is metric and imperial.

The size is 5/8" id x 35mm od x 11mm wide.

Different manufacturers use different part number schemes, but one is 6202-10-2rs.

The 6202 nails the 35 and 11 mm while the 10 nails the 5/8". The 2rs specifies both sides rubber sealed.

BTW fafnir is now owned by timken.

[awatson6]

Ok. I located 2 bearings http://www.vxb.com/page/bearings/PROD/5-8inch/kit966. Is there a document I can follow on how to remove and replace the bearings (if my single bearing quill can be converted to a double bearing quill)

[JPG]

Ok. I located 2 bearings http://www.vxb.com/page/bearings/PROD/5-8inch/kit966. Is there a document I can follow on how to remove and replace the bearings (if my single bearing quill can be converted to a double bearing quill)

That be de one! Save the second for a spare.

A two bearing quill can 'replace' the single bearing quill, but adding a second bearing requires precise machining.

Bill mayo has done so and MAY have one 'available'.

I almost completed composing a step by step procedure, but ms/windows decided their 'updates' were more important(despite being told to do so at 0300 only!!!). So my consternation prevents me from repeating that effort(at present).

I am going back to ubuntu for the rest of the day!!

[trainguytom]

I've always used a 1623-2rs bearing, which is 5/8" x 1 3/8" x 7/16". They measure out to the same (35mm, 11mm) as the previously mentioned bearing. I'd recommend going with an ABEC-3 grade like this one. http://www.ebay.com/itm/1623-2RS-Premium-Bearing-5-8-x-1-3-8-ABEC-3-1623-RS-Bearing-/390378223778?pt=LH_DefaultDomain_0&hash=item5ae45af8a2
Good price, free shipping, no failures in my machine or any machine I've rebuilt over the last several years. But regardless which you use, check for ABEC-3 rating.

[JPG]

I've always used a 1623-2rs bearing, which is 5/8" x 1 3/8" x 7/16". They measure out to the same (35mm, 11mm) as the previously mentioned bearing. I'd recommend going with an ABEC-3 grade like this one. http://www.ebay.com/itm/1623-2RS-Premium-Bearing-5-8-x-1-3-8-ABEC-3-1623-RS-Bearing-/390378223778?pt=LH_DefaultDomain_0&hash=item5ae45af8a2
Good price, free shipping, no failures in my machine or any machine I've rebuilt over the last several years. But regardless which you use, check for ABEC-3 rating.

Yes a 1 3/8" od bearing will fit in a bore intended for a 35mm bearing, but will be a bit sloppy(1.375" in a 35mm(1.378"). All quills I have measured are 30mm or very slightly more(never less).

A C3 bearing is a relatively loose bearing that allows for thermal expansion etc.

For minimal runout, a C1 bearing is preferred, but 'just try to find any'.

Pertinent 'literature'. http://www.ahrinternational.com/bearing_radial_clearance_explained.htm

[billmayo]

I've always used a 1623-2rs bearing, which is 5/8" x 1 3/8" x 7/16". They measure out to the same (35mm, 11mm) as the previously mentioned bearing. I'd recommend going with an ABEC-3 grade like this one. http://www.ebay.com/itm/1623-2RS-Premium-Bearing-5-8-x-1-3-8-ABEC-3-1623-RS-Bearing-/390378223778?pt=LH_DefaultDomain_0&hash=item5ae45af8a2
Good price, free shipping, no failures in my machine or any machine I've rebuilt over the last several years. But regardless which you use, check for ABEC-3 rating.

Always try to find a ABEC3 or higher rated bearing. This company is where I have been buying all my bearings for the past few years. I highly recommend them. Excellant seller to deal with. They were happy to answer any questions that I had.

LocTite sells several different bearing compounds to help tighten up any loose bearings clearances.