Cross feed jam

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GordonL

Aluminum

Joined

Mar 11, 2006

Location

Michigan

• Aug 30, 2015

• #1

I have a 13" SB in good shape. Recently the cross feed screw jams, worse under power. I must release the power, back off and then reengage. I first thought that the problem was in the lever clutch on the apron. I took that apart and cleaned it. The clutch shaft was slightly bent but I was able to straighten it. That was not the problem. I have checked the gears in the feed train and do not see damaged or missing teeth. It is not in the feed screw or the brass nut because It happens even with the nut disengaged. Any thoughts?

Gordon

 

Richard King

Diamond

Joined

Jul 12, 2005

Location

Cottage Grove, MN 55016

• Aug 30, 2015

• #2

Did you check the taper gib on the ways?If you disinagge the clutch do you have this problem manually turning the cross-feed screw? If you do the gib is probably sliding in to deed. Missing a read gib screw?

 

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GordonL

Aluminum

Joined

Mar 11, 2006

Location

Michigan

• Aug 30, 2015

• #3

I am sure that it is not the gibs. It seems to happen at the same point on the dial for example at 120 every time it comes around to 120. The next time it will jam at a different point because the clutch was engaged at a different point. I certainly acts like a bad gear but I certainly cannot find one. I may have to take more of the apron apart.

 

SBLatheman

Titanium

Joined

Jul 7, 2008

Location

South Bend, In

• Aug 30, 2015

• #4

Does it happen feeding in either direction?
Do you have the CF screw assembly with thrust bearings?
Ted

 

Richard King

Diamond

Joined

Jul 12, 2005

Location

Cottage Grove, MN 55016

• Aug 30, 2015

• #5

I have see where the dial gets a gull on it's back side where they rub. How about checking that and and if it is stone it low and add a few drops of oil on assembly. Also check the feed gear and feed screw gear that turns the cross-feed screw for a bent tooth burrs or a chip stock in it. Rich

 

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GordonL

Aluminum

Joined

Mar 11, 2006

Location

Michigan

• Aug 30, 2015

• #6

I am not sure if it happens both directions. I do have the screw with thrust bearings on both ends. There was a lot of gap (about 3/32) so I recut the groove in the sleeve which the pin goes into so the play is much less. I have not put it back together yet to see if that helped. My feeling is that it would not help but I have been wrong before. It is possible that the long spur gear on the screw could move far enough to jam in the gear protruding up from the apron.

 

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GordonL

Aluminum

Joined

Mar 11, 2006

Location

Michigan

• Aug 30, 2015

• #7

It is not the dial. It is so jammed that I have to release the power feed and back it off a few degrees to release it. then I can resume the feed. It has been happening occasionally for a while but now it is happening a lot. It is human nature to ignore it thinking that it will cure itself. Never happens but we keep hoping.

 

Richard King

Diamond

Joined

Jul 12, 2005

Location

Cottage Grove, MN 55016

• Aug 30, 2015

• #8

When you assemble it, don't lube it and paint everything with Dykem layout fluid the run it, take it apart and see what it looks like.

 

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GordonL

Aluminum

Joined

Mar 11, 2006

Location

Michigan

• Aug 31, 2015

• #9

I got everything back together and so far it seems to be working OK. I really did not find anything wrong other than the slop in the thrust bearings which I corrected. I have no idea why it was there in the first place. There was no wear and I had to rework the sleeve to correct it. I guess I will try it for a while and see if the problem is really fixed.
Thanks for the ideas.