Hand saw with depth stop?

I sometimes get bikes in with seized/stuck seatposts, is there such a thing as a slotting hand saw with depth stop to avoid cutting into the seat tube or do I need to invent one?

I had the same problem.

Try making a wooden clamp to go round the seat post - two pieces of 2x2 say 12 " long bolted together with a hole drilled through slightly smaller than the seat post so you can grip and twist the post. think tap wrench for design. if necessary line the inside of the hole with leather. You can then gently heat the down tube with a paint stripper or hair dryer on low. keep it at a good distance and move it around constantly to avoid damaging the paintwork. The leverage on the clamp should allow you to turn the seat post and work it up wards. You can also tap the wooden clamp upward to help to release it . The down tube is generally thinner than the seat post so should expand more quickly and release. If that fails google BAHCO 208 hacksaw blade holder but it will be a slow process!

With a good twist on the clamp, mine came out quite easily in the end

Good luck .

Did you note the tommy bar hole drilled in the seat post?

David

I, too, occasionally have the same problem. A hefty slide hammer can work. If the post is scrap, and they normally are, if you can bang the post in a little to shift it, a slide hammer will often then get it out.

I did - but firstly the tommy bar approach means damaging the seat post beyond further use. In addition the looseness you generally get with a tommy bar tends not to allow the steady constant force you can impose with a well fitting clamp . Also the guy suggested this is more than just a one off, so making a clamp which will allow for a little variation in seat post diameter gives him a tool he can use over and over again when the need arises. Finally, setting the clamp up against the un removed seat not only doesn't damage the seat post but also allows the clamp to have a solid face to work against for upward taps which you cant achieve easily with the tommy bar approach .

Hope this is helpful.

It sounds like you are trying to salvage a seat tube while destroying (cutting) the frame!
As the frame is very thin would a pipe cutter (clamped on cutting wheel) work? Or perhaps a pipe cutter or just block of wood with hole in it modified to hold a v-tool to score / cut a groove as you rotate it.

A longitudinal cut / scraped groove might relieve the griping force while allowing in oil and have some chance of repair.

Edited By Bazyle on 24/07/2017 17:23:18

RRMBK

If you can get the seat post out with a wooden clamp as you describe, that isn't a seized seat post, it's a lightly stuck one!!

With a properly seized one, the post is invariably scrap. Brute force, whilst not damaging the frame in the process, is normally the only solution, so the post becomes the sacrifice.

My worst one so far is an ally post stuck in a steel frame...........but the previous owner had sheared the post off in a botched attempt to remove it, so the remainder was seized three inches down the seat tube

Edited By David Standing 1 on 24/07/2017 17:28:41

No, the seat tube is the bit of the frame that holds the seat post. The OP is definitely trying to save the bike frame!

A decent penetrating oil (not WD40) and some gentle heat to persuade it to penetrate as much as possible, plus some time to soak in, maybe overnight, would be how I would start. More heat when you try and twist it out. If you can clamp the frame to something really solid that would be a big help - modern frames are so light that tapping anything clamped to the seat post will just move the complete bike rather than just the post.

I would go along with the slide hammer. Make a threaded piece about an inch long with an outer diameter that will just pass through the seat post, and put an m12 or 1/2inch thread through it. Lock it onto some studding with a couple flock nuts. Slide the piece in and locate it in the frame below the seta post. Stand on the frame and using a good sized lump as a slide hammer on the studding, hammer away. I have used a slide hammer on a lot of corroded joints with dissimilar metals and it has mostly worked. Trying to collapse a part may make things worse by swelling as it is misshapen.

The way I got the buried seized seat post out was to take the bottom bracket out, pass a long piece of studding through the seat post right down to the bottom bracket, I selected a couple of stout washers just smaller than the ID of the down tube, put them on the studding, then a nut.

The top end of the studding was clamped in my 5" record bench vice, and I then used the frame as the slide hammer!

It is a bit of fiddling getting the washers and nut on the studding, and you need to move the frame in the same plane as the studding when using the frame as the slide hammer, but it is very effective as all of the moving force is directed at pushing the seat tube up and out.

I also wouldn't recommend this for a carbon frame!!

If you are going to scrap the seat post why not hammer some dowel rod inside the seat post to stop it crushing then clamp the seat post in a vise and use the frame as leverage to twist the post loose .

You can make a depth stop- bend a bit of thin steel into a channel shape then file to size and squash it onto the hacksaw blade. A drop of poxy glue if needed. Hard work though.

Something that vibrates (ooh)

I'm put in mind of jammed-solid MT tapers which literally drop out when side milling

So suspend the entire bike by the seatpost in the vibration equipment and set it going

....Of course you will have to build a vibrator machine first....

edit: An attachment on a decent oscillating saw?

(just mulling aloud)

Edited By Ady1 on 25/07/2017 09:41:14

I'm with Steve Pavey Ditch the WD40, get some Plusgas Liquid rather than aerosol if possible and let it soak

Roy

I ended up drilling mine out with a 1/2 mm undersize blacksmiths drill.

It worked, but very fiddly.

Further on a depth stop- Just come across some hard plastic clips for clipping paper together- a bit would make a depth stop.

Another thought would be freezer spray on the seat post while gently warming the seat tube.

**LINK**

I don't think the freezer spray will damage the paintwork, especially if sprayed on the inside and may be enough to break the seizure.

Here's a guy who has made a business from removing stuck seat posts:

http://www.theseatpostman.com/home

Adding to the tommy-bar suggestion. Could you have one person insert and apply pressure to a tommy bar while another person strikes the top of the post with a nylon or similar hammer, a bit like an impact driver?

Ed.

Edited By Ed Duffner on 25/07/2017 17:37:18

Why not fill the post with pipe freezing spray?

Neil