36 Snyder expanding lock bolt type seat post clamp

[mrg]

Anyone have experience with a expanding lock bolt type seat clamp, I had this Snyder V-70 carcass ( Hawthorne ) hangin in the shed for yrs and always wanted to do something with it so dug in the parts pile this afternoon and thru this Klunker together, rides pretty good but things will change and have to figure out that one yr only, 36, wedge type seat post clamp, can't get it real tight. It's 3 pieces a top nut, threaded center section and the collar piece, tightening the nut pulls up the center section that spreads the collar squeezing in the frame and around post, the unit that's on there has vice-grip marks but its the center threaded section that turns with the nut when almost tight, I have a second unit ( pictured in pieces ) I'm going to try tomorrow but wondering if others have had this problem? @rustjunkie ?

 

[mrg]

Just found this, was it a not tightening issue on yours, now wondering if being out of threads is the problem? @SKPC ?

What bike did you ride today? | General Discussion About Old Bicycles

1937 Elgin Oriole on the road this evening. The good part about where I live is it's rural, which is also the not so good when it comes to riding bikes. People tend to drive very fast on the farm roads, so you have to be hyper vigilant when riding.

thecabe.com

 

[WillWork4Parts]

I've not dealt with this setup, but yeah, looks like a compression fitting that's run out of threads. I'd hit the threads lightly with a thread file to knock off the crust(threads only), put some grease in the threads, then find an 1/8" washer to put under the nut. Hopefully that gives you the extra pull on the collet to grip the post. If that doesn't do it, I'd suspect too small a diameter post.

 

[WetDogGraphix]

Anyone have experience with a expanding lock bolt type seat clamp, I had this Snyder V-70 carcass ( Hawthorne ) hangin in the shed for yrs and always wanted to do something with it so dug in the parts pile this afternoon and thru this Klunker together, rides pretty good but things will change and have to figure out that one yr only, 36, wedge type seat post clamp, can't get it real tight. It's 3 pieces a top nut, threaded center section and the collar piece, tightening the nut pulls up the center section that spreads the collar squeezing in the frame and around post, the unit that's on there has vice-grip marks but its the center threaded section that turns with the nut when almost tight, I have a second unit ( pictured in pieces ) I'm going to try tomorrow but wondering if others have had this problem? @rustjunkie ?

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Mark, I see the problem...
My TriBar has one and I had to figure out how to get it out to use a longer seat post.....

Looking at this pic, I pointed out the gap at the top & bottom, wider at the top than bottom.....

It's a wedge, that is no longer a wedge, it should have a "Bell bottom" look to it. (Drawing is exaggerated)
I'll bet that the seatpost wasn't all the way in, past the bottom of the wedge. The wedge part is thin at the top, thicker at the bottom & if the post is above that thicker part, it won't "Wedge" it. That' why it seems that you are running out of threads.

I was also having an issue when I was re-installing it.. I put it together on the post itself, with the nut on just a few threads because of the wedge spreading it too much and placed it in the tube. It was a little tight, so I used a box end wrench that hit the nut but not the threaded part and slowly hit it while rotating it around till it was flush.
I also wire wheeled the bushing and took a brake cylinder hone and cleaned out the tube. A little lube and bingo....
Hope this helps..

 

[WetDogGraphix]

Anyone have experience with a expanding lock bolt type seat clamp, I had this Snyder V-70 carcass ( Hawthorne ) hangin in the shed for yrs and always wanted to do something with it so dug in the parts pile this afternoon and thru this Klunker together, rides pretty good but things will change and have to figure out that one yr only, 36, wedge type seat post clamp, can't get it real tight. It's 3 pieces a top nut, threaded center section and the collar piece, tightening the nut pulls up the center section that spreads the collar squeezing in the frame and around post, the unit that's on there has vice-grip marks but its the center threaded section that turns with the nut when almost tight, I have a second unit ( pictured in pieces ) I'm going to try tomorrow but wondering if others have had this problem? @rustjunkie ?

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Mark, if you stick the seat post in the wedges, see where it stops in that first wedge. I bet it won't come out the bottom. It needs to be out the bottom, if only 1/8" for the wedge to work correctly.

 

[mrg]

Now that I checked the threads are maxed out, post is all the way thru, put a washer under the nut but threads on nut not so good, probably didn't help trying to screw past the end of threads on the inner wedge or 87 yrs of ware ( was only used for 1 yr so who knows ), swapped to out to the other unit with better threads and a washer and seems better, didn't want to tighten to much till I get better washers and then I'll experiment a little more.

 

[WetDogGraphix]

Now that I checked the threads are maxed out, post is all the way thru, put a washer under the nut but threads on nut not so good, probably didn't help trying to screw past the end of threads on the inner wedge or 87 yrs of ware ( was only used for 1 yr so who knows ), swapped to out to the other unit with better threads and a washer and seems better, didn't want to tighten to much till I get better washers and then I'll experiment a little more.

Mark.. Here's some measurements from mine.....

Seat tube OD...


Bushing head OD...


Amount of threads on mine (and it's tight), also gap measurement.


Questions.....
Does your bushing drop in easily, or do you have to force it in & out?
What is the OD & ID of your seat tube?
Does your wedge still have this profile, or does it look like it was ground down?


One of the things I noticed in your pic here is that the wedge is way up in there, and it shouldn't do that...Like your wedge isn't a wedge.


If your tube OD is larger than mine, that could be the issue. If the opening is too large you can do a couple of things..
One is to make some brass bushings like these to go around the bushing to decrease the dia. of the seat tube, and or do the same where the wedge goes into the bushing.


Since you have them out, I would put the seat tube bushing in a vice and squeeze it down to the ID of your seat tube, put the nut on the post, slip it thru the bushing, put the wedge on with the seatpost out at least 1/8" and shove the wedge in and see how for it goes. If you have more threads than what I show in picture of mine before tightening, I would go the brass insert route to decrease the tube ID. That way you won't damage the nut or threads anymore... I have some extra brass sheets laying around and would more than willing to make you some to try...
Also, for those that aren't familiar with these, I made this little cutaway drawing to show.. They are quite simple when you've messed with them.

 

[mrg]

Well ended up swapping the unit in the picture ( didn't look as nice but nicer threads ) with the one on the bike and a different seat post and didn't need a washer and seem to work ok but I can see why it only lasted 1 yr., both appear to not have much wear, they pull up further without post but the whole thing is a pain, a simple clamp/bolt is much eaiser and would strand up to much more use/abuse than this expanding lock bolt type, can't see these loosened/tightened many times over years ( I know I don't want to move it many times ), my next option was to use a quilled post and tried a few just to see when it was apart ( Monark, Shelby, AMF ) but none of them would fit all the way in the frame so probably would have to pound in!, last option would be to slit the top of the frame and put a standard clamp but that kinda destroys rare 1 yr only frame. didn't take any measurements, hell have a couple style micrometers I haven't used in yrs and not even sure where they are. tomorrow installing a new 3 spd shifter/cable/actuator and put some miles on it and we'll see how the seat post holds up.