J-series clutch actuating pin relocation

[ThinWoodsman]

I'll probably answer this myself in the shop tomorrow afternoon, but thought I'd save some time by asking here first.

I have a Bridgeport J-series round-column mill (1955 by the serial #). It has been stuck in back gear for awhile, meaning that the clutch doesn't seem to engage when moving the clutch actuating handle forward. I was able to swtich gears prevously, so please none of those"are you sure you're moving the backgear lever as well?" responses.

Looking into this, the problem is usually caused by the holes for the clutch actuating (cam) pins being stripped. I removed the two pins this afternoon, and sure enough, one of them is stripped.

I need to rotate the bearing assembly/bushing so I can drill and tap two new holes for the cam pins, or use the backup holes if they exist (kinda hoping they do, and they're not stripped too).

My question is: can I do this without taking part the head? Maybe use a pin spanner to rotate the bushing, with spindle locked, or in back gear? I have the appropriate rebuild book (from H&W I think), and it looks like a fair amount of work if I need to take the head off.

 

[Cadillac]

If your talking of the lever on top of head which is either forward or to the right. Yes you can service without disassembling the head. Remove the two dowel pins it rides and the ring should come right off lifting it. I just rebuilt my top section all new bearings. On my collar it had two sets of The little Allen’s that lock those pins. Don’t know if it’s stock I think so because both sets of my screws were fine.

 

[ThinWoodsman]

Thanks, I'll give it a go later today. I know the ring with the handle comes off (removed it to check the threads on the bushing) but didn't know if there was anything underneath holding the bushing in position. Dug up the pin spanner that came with the mill this morning.

 

[JimDawson]

It is a bit unusual that the machine will not go into direct drive. That means that the assembly is not dropping down into the dogs in the drive. Normally the opposite problem exists, the pins or cam wear and won't lift the dogs out of the bull gear.

Try tapping on the top of the cam with a dead blow hammer to drive it down. Some cleaning and lubrication may be in order. This may require removing the top housing to get to the parts.

 

[Cadillac]

There are 4 springs that push the bearing Assy. Downward to engage the drive. The cam action is what counters or compresses the springs raising the bearing Assy. to put in high gear.
To remove the upper half all that’s required is remove the motor can leave electrical if has a main disconnect. Remove the six Allen’s around the seam from upper to lower. Then pull up nothing should stop you except grim on top of spindle area. Would give you a chance to inspect drive hub ears,clean and check for grease in bull gear area. Mine was pretty much dry after 40yrs of service. Not a hard job at all.
You’d only need a spanner pin wrench if you want to take the bearing Assy. apart. That’s what those collars are for on top spindle area. One is for inner race and other is for outer.

 

[ThinWoodsman]

Awesome, thanks guys. Will follow up.

 

[ThinWoodsman]

OK, I yanked the motor and unbolted the top of the motor/pulley housing. I couldn't remove it fully; after lifting it about an inch something caught in the pulley/spindle area, and I didn't feel like forcing it. Held it up on blocks while I poked around.

Inside the housing, there was a lot of crud. Pretty sure that's the technical term. Used paper towels to scrape the big chunks out, got in with a plastic gun-cleaning pick around the base of the pulley in case there was debris preventing it from lowering.

This didn't really help. I put the cam ring back on, held the housing in place, and still no-go. Tapped the cam ring with a dead-blow and click, there it goes. Worked ike a charm.

So it looks like a disassembly + clean/lube of the pulley is in order to get things in proper shape, but for the moment I can switch to high gear with a dead-blow tap. I'll leave it at this until the weather improves, or I forget how heavy that motor is.

 

[Cadillac]

The crude on the splined part of the spindle is probably what's stopping you from lifting all the way. The bearing Assy. Moves only 1/2" on the spindle. The splined 6" above get the years of dust built up on them. I had found swarf in the drive dog area built up couldn't tell or figure out how it could even get in there. Only way I can come up with is they fell down the splines of spindle, or having in low gear and the chips flying with the belt guards off and somehow got in between the front pulley and housing? Try some light weight oil down the splines it will lube the spindle that contacts the bearing Assy. In question. Good to hear you freed it up.

 

[ThinWoodsman]

Try some light weight oil down the splines it will lube the spindle that contacts the bearing Assy. In question.

Good idea, might flush it out. I can try that without even taking the motor off.

One further detail for the curious: there is only one pair of set-screws for the cam holes, so there likely isn't another set of cam pin holes in the bushing. Haven't decided whether to drill and tap a second pair of holes, or just ream and tap the stripped hole and use a bushing and/or replacement cam pin. The latter might be less work (certainly from a layout standpoint).