Into the Head - Bridgeport 2J2 Variable Speed

[ctwo]

Hi Folks,

I'm stuck. How to take off the main spindle drive pulley? I already took the clip off the shaft just above the pulley, but it's stuck and I've already whacked it around a bit...

Also, how does it sound with a hand spin? It's louder than I like when running. I think the top drive bearings could use some attention. Spindle might be OK, but there is a slight knock on the motor bearing that I might be able to ignore.



http://www.youtube.com/watch?v=RzI10QjNg7s

[ctwo]

or not...

[JackF]

I have the same problem with my Comet 3Kv. I took it apart when I got it, 6-7 years ago, to clean it up and check for problems. Went to take it apart not too long ago and the pulley wouldn't come off. I'm thinking when I tap the draw bar to free the R8 collet the draw bar mushrooms the shaft just a little each time till eventually the pulley won't come off. If I end up taking this mill with m on the move I will file the shaft down, get the pulley off and chamfer the shaft to prevent further problems.

[ctwo]

I saw a few videos of these varispeed heads running and I guess they are just loud beasts. Not like the step pulley machines that I remember where all you heard was the whine of the motor...

[ctwo]

How much noise is too much? I was just looking at a top end rebuild kit, but was thinking of just cleaning everything and repacking the bearings.

My machine made a bit more noise than these, I think but it's hard to say in the video.

http://www.youtube.com/watch?v=ZLSHfsHvOzo

http://www.youtube.com/watch?v=YbRZvcHTOtQ



And this one sounds good, smooth whirring, but still loud!
http://www.youtube.com/watch?v=w57ADSu3TT4

[JHenriksen]

The fixed side of the spindle drive pulley is pressed on to the extension hub. The bottom of that piece is also the brake drum. You need to remove the housing that the shaft and pulley are part of. I dont normally remove the fixed pulley from the shaft.
Noises from the varispeed drives is normally associated with worn keys and bushings, The nature of the drive belt is to always try to tip the sliding pulley and cause the bushings to wear on the outer edges. The keys are plastic. this prevents undue wear on the keyway in the shaft.
The bushings in the sliding pulleys must be glued in place. That will help keep the edges from chipping.
I use a 'plastic welder' labeled acrylic glue for this. The bore needs to be cleaned of old glue, the shaft needs to be greased or coated with alot of car was as a release agent and when the bushings are glued in,m the pulley is put on the shaft until the glue is set.

[ctwo]

Allright, Thanks!

I think you're right that next housing needs to come off. There is a bearing under there that can be replaced, or cleaned and repacked? The shaft wabbles on that bearing and much of the sound seems to come from there, so I just wanted to check it. It also seems hard to get it into back gear, once the gears mesh, the lever has resistance and is being hard to stay into back gear, even when I rotate the spindle and I'm setting it in. But I read there is a difficult adjustment once the back gear housing is removed, and not to remove it.

[Harold_V]

The shaft wabbles on that bearing

That would send up a red flag for me---even if it made no noise.

and much of the sound seems to come from there, so I just wanted to check it.

Indeed! Even without noise, I'd be concerned, as a bearing should have the ability to keep a shaft reasonably erect. With noise? My money says there's something amiss. Looking forward to your report.

Harold

[JHenriksen]

When the top bearing is not supporting the spindle extension hub, it does wobble quite a bit even with a new bearing.
The next lower housing should not have to come off to remove that shaft, there are bolts that hold the brake housing in place that go in from the top.
Most rattling and knocking i have repaired is due to worn keys and bushings in the pulleys. I do not replace the bearings every time i replace the bushings keys and belts on a machine. If I replace bearings, i always specify the ruber seal instead of metal shield bearings. Rubber seals can be removed and reinstalled. This allows cleaning and regreasing bearings if needed.
Difficulty in engaging and disengaging back gear/high gear is probably just having to get the teethe of the cluth aligned to engage. It is normal to have to wiggle the spindle when shifting back to high gear.

[ctwo]

I'm about to break loose the back gear housing. I heard this should not be removed because an adjustment needs to be made when putting it back.

I'm also wondering if the kits include all the bearings, except spindle bearings?

I'm looking at H&W. http://www.machinerypartsdepot.com/site ... age/601085

That's 7 bearings total. It looks like 5 on the main shaft and two for the back gear pinion.

[ctwo]

Tonight I might bust the final housing off the head, exposing the area under the back gear. Unless there is some reason I shouldn't, which I suspect there is... is there?

What is that factory adjustment? I read that the housing should be left to float until the head can be run and then tightened final. This will self-align the spindle in the driven shaft. Is that all?

Does anyone know what the two set screws are in that final assembly?

My bull gear was dry. I found grease above the cover plate, but none on the actual gear?

I'm also starting consider the spindle bearings again. Right now I can hear them with a hand turn, but want to get the top bearings off to eliminate some of that noise. I can hear a piece of grit somewhere and I think it is one of the top drive shaft bearings (I think there are two more just below the bull gear)...

I do not see how the spindle bearings get oil, but probably none because they are supposed to be sealed with grease. They sound like dry bearings to me, whirring with a hand spin, but the spindle spins free...

[John Evans]

BP spindle bearings are OIL lubed ,constant loss system . You squirt oil in the one port daily and it runs down through the bearings .