Drive sheave bearing removal on CY 16

The clutch/drive sheave on my CY 16 was rattling and generally sounding suspicious so I pulled it apart and found some nasty bearings in the sheave. Looked like they hadn't been lubricated in years and what was there looked like black tar.

The parts diagram from Monarch appears to show a different setup with bearings held in place by retaining rings and a space between the two bearings. However, my machine appears to have a sleeve that the runs through the ID of both bearings and I see no retaining device so I assume it is pressed in place.

Before I go pushing on this thing to disassemble it, is there anything that I' missing?

I really can not advise on this clutch. The Clutch on my CY is an Edgemont an isn't quite like this?

I know that these bearings require greasing frequently.

In case not already found, greasing "door" on FRONT of belt / clutch guard nestled up against head stock casting upper rear

johnoder said:

In case not already found, greasing "door" on FRONT of belt / clutch guard nestled up against head stock casting upper rear

Click to expand...

Thanks. I wondered what that door was for until I pulled apart the sheave and saw the asphalt-like grease, wrecked bearings, and then noticed the long-neglected grease zerk on the back side of the sheave! Apparently the lathe's previous owner wasn't aware of the door either.

One of the bearings had some false brinelling damage so I'm replacing both.

Followup

The bearing/sheave assembly was, in fact, a push-together assembly. A few rap with a hammer and a block of wood is all that is needed to disassemble.

My lathe was built in 1944 and the bearings were Timken a 368/362A pair although it looks like someone has been into them before and I'm not sure these are original. The biggest indicator is that these are taper roller bearings and there is no good way to pre-load them without making special shims.

Here is the complete assembly for the benefit of any future CY owners seeking this info. Note that I am suspicious this may have been modified from the original Monarch design.

*D'B=6bk said:

The bearing/sheave assembly was, in fact, a push-together assembly. A few rap with a hammer and a block of wood is all that is needed to disassemble.

My lathe was built in 1944 and the bearings were Timken a 368/362A pair although it looks like someone has been into them before and I'm not sure these are original. The biggest indicator is that these are taper roller bearings and there is no good way to pre-load them without making special shims.

Here is the complete assembly for the benefit of any future CY owners seeking this info. Note that I am suspicious this may have been modified from the original Monarch design.
View attachment 273781

Click to expand...

I agree, looks like your taper bearings are backwards compared to my Edgemont Clutch. This is the same orientation as a Corvair rear hub, using shims to to get proper clearance. (Got to use a Corvair reference) These are a pain to get correct but not an unheard of design. The practice is to assemble, measure end play then add a shim to bring up to 0.001" end play. It is not required to have "preload" on these bearings. Actually just a small amount of end play. Not like the spindle bearings...

All the bearings in the headbox other than the spindle bearing are adjusted to "loose" according to Monarch. I would classify loose as 0.001" to 0.003" end play. The spindle bearings, according to Monarch, are to be less than 0.001" endplay. Mine is set at 0.0005" end play, using a small pry bar to move the spindle.

The bearings can be pricey but first look for NOS bearings. I would stick with Timken, mainly for continuity. I would suggest try new bearings and maybe you spacer will be adequate. Otherwise, you may need to turn down the end of your inner spacer? Not sure what the big spacer is for unless it sits on the race of one of the bearings? The thickness of your big spacer could be your adjustment?

The Edgemont inverts the cones and uses a locking nut to tighten bearings.

A couple of links to new bearings.

Tapered roller bearing 368-362A-TIMKEN - 50.8x88.9x20.64 mm | 123Bearing

2x 368-362A Tapered Roller Bearing QJZ New Premium Free Shipping Cup & Cone Kit 748139069443 | eBay


I'll check and see if I still have my used bearings. Mine were not bad, just decided to replace all bearings in the head stock.

From the monarch manual. Look like #23 is the Sheave Bearing spacer...

I got the replacement bearings installed today. I'm 99% sure the outer spacer was an add on by a previous owner. It actually interfers with the cage on the new bearings (not Timken but an import based on the recommendation of my bearing guy). The outer spacer is definitely not Monarch quality. The finish is very poor even for a rough cut. I did not use it when reassembling the drive.

The stackup measured out to be 0.02" of preload (i.e., the nominal stackup of the bearings, bearing cap bosses, and inner spacer were 0.020" longer than the face-to-face dimension of the drive sheave hub). I reusued the original shim and it at least feels reasonable. The sheave turns easily by hand and doesn't turn the input shaft when the clutch is open.

Sounds like you got it! Good work!

William