520 carriage not sliding

[BigJohn]

Upgrading a mark V to 520.The new carriage slides about halfway down the tubes and then jams tight. I've tried cleaning and waxing the tubes as well as rotating them. I got a new replacement carriage and the problem persists. I pulled one tube out an put it in the new carriage and found that it slid smoothly. I tried the same with the other tube and it jammed about halfway down. I checked the diameter of the tubes with a micrometer. The one that slides easily is .444-.442. The one that jams is .446 at the jam, .444 along the rest of the length. I'm thinking of hitting the tube with some steel wool and seeing if I can remove a few thousanths and get the thing to slide. Anyone else have this problem and a solution?

[JPG]

0.444? What 'tubes' are they?

[everettdavis]

Take the carriage lock assembly out and slide it. I wonder if overtighten ed carriage lock has deformed the way tubes. I don't relate to the measurements you provide.

Everett

[ChrisNeilan]

I’m wondering if the wedge locks are out of whack... one side may be tighter than the other.

[dusty]

I’m wondering if the wedge locks are out of whack... one side may be tighter than the other.

I was thinking the same thing BUT why would the one tube slide part way in and then freeze up (after that same tube slide all the way through on the other side).

Both of the replacement/new carriages jam. This tends to negate my original thoughts. The wedges are not likely to be the cause.

At any rate, I would pull the headstock off and pull the lock mechanism for inspection and the possible need of realignment of the wedges.

After doing that, if the problem was not fixed, I would be stumped.

Is this an upgrade kit from Shopsmith or are we talking about recycled hardware?

[Hobbyman2]

What happens if you switch the tubes ?

[dusty]

What happens if you switch the tubes ?

Reread the original post for your answer.

[videobear]

0.4XX?? That can't be right, the way tubes have a much larger diameter than that. And you said you'd "rotated" the tubes...a common cure for slightly bent tubes; you didn't say whether you'd swapped them around, one for the other.

I'd contact Shopsmith on this. If the old carriage rides the tubes smoothly, the new one ought to as well. Whether that means something is wrong with the carriage, or the tubes are out of spec, would be up to SS.

[BigJohn]

Wow! Thanks for all the suggestions. I've turned this thing every-way but loose but it still jams. I called Shopsmith and spoke with the supervisor who inspected the carriage that was sent me as part of the 520 upgrade.After some discussion, she said the problem was probably a deformation in the support tube (maybe caused by tightening the headstock or carriage too tight in the past, but who knows?)

I still don't understand how one carriage hole slides down both tubes easily, but one hole(the one near the handle) jams halfway down. The old carriage assembly moves smoothly down both tubes as does the headstock. The replacement carriage jams in the same place as the the original one they sent.

They gave me a discount on a new tube and asked me to try that. Should arrive in a week or so.

I think i'll take a dremel tool with a grinding disk to the sticky tube and see if that loosens things up while I'm waiting.

[dusty]

Wow! Thanks for all the suggestions. I've turned this thing every-way but loose but it still jams. I called Shopsmith and spoke with the supervisor who inspected the carriage that was sent me as part of the 520 upgrade.After some discussion, she said the problem was probably a deformation in the support tube (maybe caused by tightening the headstock or carriage too tight in the past, but who knows?)

I still don't understand how one carriage hole slides down both tubes easily, but one hole(the one near the handle) jams halfway down. The old carriage assembly moves smoothly down both tubes as does the headstock. The replacement carriage jams in the same place as the the original one they sent.

They gave me a discount on a new tube and asked me to try that. Should arrive in a week or so.

I think i'll take a dremel tool with a grinding disk to the sticky tube and see if that loosens things up while I'm waiting.

You speak only of the carriage. Does the headstock slide end to end with a consistent amount of resistance as you pass over "the bad spot".

If the tube(s) was/were damaged enough to jam the carriage, I would think you could feel and/or see that.

Good Luck with this.