Ulsa Endpin problems

[bejoyous]

I have a nice Ulsa endpin, but the screw is slipping.

I've taken a round file to deepen the grooves on the rod, but I think the screw itself needs some filing.

However, there seems to be something which prevents the screw from being removed. I'm not sure if this is part of the design or if there is just some dirt on the threads. I've never been able to remove it.

I'd like to remove the screw and shape the end to match the groove on the rod, but I'm afraid if I force the screw out the threads would get stripped and then I'd be really "screwed!"

So...I was wondering if there are any other TBers that have an Ulsa endpin. Can the screw on your's be removed easily or is this part of the design? Have you had a similar experience? Etc.

And... if there are any luthiers out there with experience with this type of endpin, if you know how I might remove the screw without stripping it.

[Jake deVilliers]

Which Ulsa model do you have Brian?

[bejoyous]

I'm pretty sure it is the 435R model. I think Peter Chandler got all his materials from this supplier.

[Jake deVilliers]

If I remember correctly, they just damage the threads a little on the end before inserting the pin, in order to keep the screw from coming loose and getting lost. You could force it out but... Have you tried lubricating the threads so that there's no torque lost when you turn the thumbscrew?

I would be working on the pin, myself.

[bejoyous]

So, I've sanded the groove on the pin so the screw catches the pin well, but the cork is a bit worn out from sliding the pin in and out to use a wheel too many times. When I have the pin at my playing height, there is a bit of play so the bass wobbles front and back. (Hmm, maybe the bumps from the sidewalk have caused the pin of the wheel to wear out the cork?) Not a lot but it is annoying and I'm constantly wondering if it's going to break down in concert.

Of course this is happening when I'm trying to get ready for an audition!

So, I'm going to order a new Ulsa endpin (so I know it'll fit the hole properly) and replace it. How do I go about this? I guess the soundpost will fall no matter how delicate I try to be. Maybe I should just take it to a luthier to "gitter-dun."

[Cody Sisk]

If the soundpost is fitted properly (or too tight) it shouldn't fall. If it does fall, it's time to see a luthier anyways because your post is too short!

[arnoldschnitzer]

The problem is that the soft brass of the screw has mushroomed from encountering the hard stainless steel endpin. To repair it, you have to force the screw out, and then file the end down to remove the mushrooming. In the process of doing this I have broken a few of these thumbscrews. So have a spare endpin ready, or a drill press, tap and replacement screw.

[bejoyous]

No the screw is fine, the cork lining is worn so the pin pivots at the screw. This causes the lower end of the bass to move forwards and backwards about an inch, especially when I'm playing eighths or sixteenth notes forte or more.

[arnoldschnitzer]

You can re-bush the endpin if you are handy. Leather lasts much longer than cork.

[bejoyous]

So, the new Ulsa endpin arrived. I took the old rod and placed it in the new socket to see how it fits. And it turns out when I cut the rod to stop the inside part from vibrating sympathetically, I cut it too short.

I recently increased the height of my endpin to raise the bass a bit and in doing so the inside end of the rod didn't reach to the end of the socket where there is another cork bushing.

This caused the inside part of the rod to pivot back and forth and dig out the inside of the socket bit by bit so the pivot got progressively worse.

I took the new rod and put it in the old socket and it works fine now.

If anyone is looking for just the socket part, there's an advert in the classified section.