Is anyone here a machinist? I need a seat clamp made...

[booglebug]

Originally Posted by boywander

What do you do with your the two shop then?

He probably try’s to make money, couldn’t make pocket change on this part in a job shop

[charliedid]

Originally Posted by Dr Luxurious

Long story but I need a special seat clamp.
It's for an aero post similar to the design of an Allez Sprint or a Felt TK1.
Doesn't have to me fancy, just functional.

Like:

https://cdn.shopify.com/s/files/1/00...-TK1_2048x.jpg

or:

https://cdn.bike24.net/i/mb/a4/6f/1a...int-848038.jpg

Which bike frame is it for?

[unterhausen]

Originally Posted by booglebug

He probably try’s to make money, couldn’t make pocket change on this part in a job shop

crazy talk, make money!? There's also the simple matter of not wanting to spend a couple of days on something someone could buy for $10.

If anyone wants a better idea why someone might not try to make a part like this a significant part of the process of making a round seat post clamp (i.e. known dimensions) was documented online by Drew from Engin Cycles. https://www.instagram.com/engincycles/?hl=en

I call requests like this "should be easy for you" projects.

[Buzz Killington]

Paul Brodie has a YouTube video on the making of a seat post collar. Not aero obviously but a fun watch if you’re bored.

[tomato coupe]

Originally Posted by boywander

What do you do with your the two shop then?

Huh?

[boywander]

Originally Posted by tomato coupe

Huh?

Curious to know what do your shop produce? Ex.. aerospace, automotive, or what??

[tomato coupe]

Originally Posted by boywander

Curious to know what do your shop produce? Ex.. aerospace, automotive, or what??

Scientific instruments.

[ChainNoise]

Do you have a print with all dimensions at least?

[Dr Luxurious]

So the story is....

It's a Duratec track frame.
https://www.duratec.cz/en/612-sprinter-t11/designer/

The slot in the seat tube (at the clamp) is too wide. It allows the seatpost to rock back a tiny bit under load and then it slips. I've tried all sorts of shims and friction paste - doesn't work.

I asked a local builder (Paul Sadoff) if he could fill the void and then re-cut the tube on the front side. He said yeah but the welding process would weaken the surrounding area so the whole frame would need to be heat treated. Yikes.

So I'm thinking an easy way to do it is to get a seat clamp that goes on the post itself and mount it right above the regular frame clamp.
I've done this double clamp set up on my MTB. Easy peasy no more slippy. But the MTB has a regular 27.2 post. That clamp cost me $8.


This is the OEM clamp.
https://www.duratec.cz/en/1399-seatpost-clamp/

I thought about getting another OEM and shimming it so it fits the post but the opening is still in the back - I think it needs to be in the front or on the sides like the Allez / TK1 setups.

I tried a SS exhaust clamp but it didn't work out...

[duff_duffy]

Could you buy two OEM clamps and stack them on frame? Many years ago this worked on a BMX bike I had with same problem.

Originally Posted by Dr Luxurious

So the story is....

It's a Duratec track frame.
https://www.duratec.cz/en/612-sprinter-t11/designer/

The slot in the seat tube (at the clamp) is too wide. It allows the seatpost to rock back a tiny bit under load and then it slips. I've tried all sorts of shims and friction paste - doesn't work.

I asked a local builder (Paul Sadoff) if he could fill the void and then re-cut the tube on the front side. He said yeah but the welding process would weaken the surrounding area so the whole frame would need to be heat treated. Yikes.

So I'm thinking an easy way to do it is to get a seat clamp that goes on the post itself and mount it right above the regular frame clamp.
I've done this double clamp set up on my MTB. Easy peasy no more slippy. But the MTB has a regular 27.2 post. That clamp cost me $8.


This is the OEM clamp.
https://www.duratec.cz/en/1399-seatpost-clamp/

I thought about getting another OEM and shimming it so it fits the post but the opening is still in the back - I think it needs to be in the front or on the sides like the Allez / TK1 setups.

I tried a SS exhaust clamp but it didn't work out...

[truth]

Originally Posted by duff_duffy

Could you buy two OEM clamps and stack them on frame? Many years ago this worked on a BMX bike I had with same problem.

Yes, the budget option. If there's a lip on the collar to rest on the top of the tube, a hand file will make quick work of that.

If you're set on putting an extra on the just the post, could you shim a production clamp?

What type of exhaust clamp did you use and was it on the seat tube or the seatpost? Would a worm gear hose clamp work in either spot?

[Gsinill]

Originally Posted by Dr Luxurious

So the story is....

It's a Duratec track frame.
https://www.duratec.cz/en/612-sprinter-t11/designer/

The slot in the seat tube (at the clamp) is too wide. It allows the seatpost to rock back a tiny bit under load and then it slips. I've tried all sorts of shims and friction paste - doesn't work.

I asked a local builder (Paul Sadoff) if he could fill the void and then re-cut the tube on the front side. He said yeah but the welding process would weaken the surrounding area so the whole frame would need to be heat treated. Yikes.

So I'm thinking an easy way to do it is to get a seat clamp that goes on the post itself and mount it right above the regular frame clamp.
I've done this double clamp set up on my MTB. Easy peasy no more slippy. But the MTB has a regular 27.2 post. That clamp cost me $8.


This is the OEM clamp.
https://www.duratec.cz/en/1399-seatpost-clamp/

I thought about getting another OEM and shimming it so it fits the post but the opening is still in the back - I think it needs to be in the front or on the sides like the Allez / TK1 setups.

I tried a SS exhaust clamp but it didn't work out...

So wouldn't the Specialized one that I posted above work???

[Dr Luxurious]

Specialized is a way different size and shape (I have an Allez)

I tried an exhaust clamp like this:
https://www.quadratec.com/sites/defa...55398182AA.jpg

If I could find one with the right ID it would probably work but they come in standard inch increments: 3in, 4.5in, etc.
I would need something different and pretty precise - Like 4-3/32" or something

[JedB]

Originally Posted by Dr Luxurious

Specialized is a way different size and shape (I have an Allez)

I tried an exhaust clamp like this:
https://www.quadratec.com/sites/defa...55398182AA.jpg

If I could find one with the right ID it would probably work but they come in standard inch increments: 3in, 4.5in, etc.
I would need something different and pretty precise - Like 4-3/32" or something

Have a look at McMaster-Carr & their shaft collars. Sleeve this around the seatpost. I'm sure you could also introduce some wedge material to make up the slack between 4" and 4-3/32"

Larger category:
https://www.mcmaster.com/shaft-collars/shaft-collars/

More specific:
https://www.mcmaster.com/shaft-colla...shaft-collars/

Possibly for your application:
https://www.mcmaster.com/shaft-colla...shaft-collars/

[charliedid]

Had a customer once that drilled through the fame and seat post and put a thru-bolt in to keep it from slipping. He said it was double duty as a theft deterrent. His bike was a rolling nightmare :-)

Don't be that guy.