I have a Cook seat clamp with no bolts. The ¼-20 bolts fit perfectly but the nuts do not. I tried the 10-24 bolts and the nuts will work but the bolts are too small.

Which one is correct?

Did they have special nuts? Or special bolts?

Does anyone have a Cook seat clamp? I need to see photos of the bolts and the bolt hole area. I also need to know what size they are and what the outside diameter of the nuts and the bolt heads are. and what size the hole is for the bolts and nuts.

Any help would be appreciated.

Thanks!

Ken, I use 1/4-20x1 1/2 and added the correct nuts (zinc/silver style) that thread to those bolts, pictures in a minute

Ken, I just tried to thread the bolt I mentioned into one of my nos seatclamps, and it threads fine. CBR came with nylon locknuts also, heres the ones I purchased from Lowes:

Here's some more pics comparing CBR seatclamps to CBR stem clamps. Besides the inside diameter difference, you will notice a small indentation on the inside of the seatclamp, but not on the stem clamps. In both examples, the seatclamp is on the left, stem clamp on the right.
(ps-Dont force the bolt through, I would remove the nut and reinstall when you have the correct setup. Post up some pics, too if you can.)
Claude

What size is the hole were the nut goes?

I think I have two of the same side, the 1/4-20 bolts fit great but the nut will not fit in the hole.

The big question now is should I modify the one side and use it anyway or wait for that needle in a hay stack and hopefully find the correct side for the nuts?

Thanks for the help, I will post pics later today.

post the pics Ken, inside and out, and we can figure it out. The allen bolt side is signifigantly smaller than the nut side. Also, the STEM clamp allen side is virtually identical to the seatclamp allen side. I will post some more pics in a bit. Claude


Ok I got to thinking, CBR had 2 model stems, slant and flat (+also had uniclamp),,the slantline clamps had the same size hole on the "allen" side of the seatclamp,,,the flat stem had a signifigantly larger hole,,,however the 7/16 nut(socket size) still wont fit in the larger of the 2 (flat/red), but comes really close(maybe thats what you have?).....doesnt even come close on the slantstem clamps..............slant stem top clamps on left, flat stem top clamps on right, (seatclamp nut for size comparison)
Claude

I took some photos of what I have, this came with a Cook slant stem I bought a few years ago, I went to use it and realized the top clamps didn’t fit the bars, they were for a 1” tube not a 7/8” which is what handle bars are. So after doing a little searching I figured out the top clamps were actually a seat clamp that someone used for the top of the stem, but after seeing the clamp you posted photos of I think I have two of the same halves of a seat clamp.

Here are a few photos of what I have.

The top one in the photo is the bottom stem clamp the other is half of the seat clamp

Here are the two halves of the seat clamp

Here is the way they were mounted on the stem

In this photo you can see both halves fit the ¼-20 bolt heads; the one half should have bigger recessed holes for the nuts.


I think I may just have a buddy of mine bore the holes out on the one half to the correct size for the nuts and use it. I need to know the correct width and depth of the holes on the nut side though.

Ken, I would suggest using a step bit in a drill press for accuracy. Drill it smaller than needed, and work your way up to the hole being big enough to have to tap the nut in. Thats how snug mine fit. Claude

I have a buddy who is a machinist so I will have him bore it at work, I figure if I am going to do it then I want it to look factory. It would bug the crap out of me every time I look at it if I don’t do it right. He is also going to make me a replacement set of stem clamps so I have something to use until I find an original set of the top clamps for my stem.

You wouldn’t happen to have a dial caliper would you? I would like to know what the width of the hole is in thousands.

I have no idea exactly what size the bolts are Ken, but I can say that those darn clamps are off the hook valuable!!!

I don't know where you keep finding all this incredible stuff... You may or may not know this, but a CB seat post clamp just like yours sold for $427.00 today on Ebay!

Here it is (maybe these pics will help you out too):

sorry Ken, no dial caliper

I was watching it, the one I have isn't worth that much though being that I really only have two of the same halves. I will machine the one half out and it will go on my Cook Cruiser.

I have got pretty lucky with some of the stuff I have found, i found the stem at the St. Louis bike show a couple years ago for $100





That's cool, I'll figure it out and make it work. I know what I have to do now.

With my luck, I will have it bored out and find the correct other half the following week.