View Full Version : Tube Slug tolerance

02-11-2015, 10:46 AM
What is too big of a tolerance between the ID of the tube and OD of the slug when joining tubing?

Second, what if you use a slug that has too much tolerance/slop in the tubing? Will this cause stress issues inside the tubing?

if this has been covered I'm sorry but I couldn't find it.

02-11-2015, 12:41 PM
It helps align the butt joint more accurately if the slug is a tight fit, otherwise it's not really critical. I usually make the slug about .010" smaller than the tube ID.


03-16-2015, 9:21 AM
What is too much of a tolerance? I've got some tubing that is 0.04" smaller OD than the ID of the tube I'm trying to slug. That too much? It's loose but I don't know if there are any problems with using it aside from not lining up the tubing as well.

03-16-2015, 10:04 AM
It would be much better than nothing, but ideally you want to make it so that the slug helps take any flex stress passing through the weld zone. Four hundredths inch isn't awful, you could probably dimple the hell out of your slug (using a center punch) to make it fit snug, or knurl it up with a chisel. Of course, if you have an actual knurling tool, that would be even better.