Lost post

[Steve Walker]

Soak it in penetrating oil for a while, then knock it *down* into the frame until there's room for the new post?

[Dave]

I have been pondering this problem for quite a while and you, as well as other posters, have missed one point.

A seat post, at both ends, is formed. Rounded to make the very last few mm of the end diameter smaller. This means that at the bottom of the seat post, there should be about 3 to 5 mm ,at each side, of grip for a slide hammer and a lipped bar It is done for a reason, so as to stop the seat post from scoring the frame tube. Usually the frame damages the seat post. No problem as the seat post can be replaced quite easily and cheaply

Get a rawl bolt that will just pass through the new post and a corresponding piece of screwed rod to match the thread. Remove the bolt from the rawl bolt and screw in the threaded rod. Hold the top of the rawl bolt and tighten the rod until the whole assembly will not pass through the seat post. Back it off until it does (ensure that the items can be screwed in and out with the slightest effort). Insert the threaded bar and rawl bolt and bring it back up the tube until you can get the top of it to interfere with the lower end of the seat post. Push side ways lightly Rotate the threaded rod until you feel resistance and can't be extracted.

Find something that will fit on the threaded bar with a hole that does not exceed the diameter of the nut/washer that you will fit later and then put a nut and an optional washer on the bar Now slide hammer the seat post out. If the seat post stops coming out, hit the top end of the threaded bar and start again. If the extractor comes out without the seat post, just start again. It's your only chance.

Dave

[Dave Plowman (News)]

They certainly won't if treated like that. An adjustable reamer is a precision tool and expensive. If you had an already wrecked one I suppose it wouldn't matter.

A decent adjustable reamer of that size will cost about 30 quid. The bike cost 15...

[Matty F]

I assume that you wish to remove the residue that is left in the frame. Put a hacksaw blade into a handle sold for that purpose. Cut two slots as deep as you can in the residue of the pipe. Hit it with a cold chisel until it splits and comes out.

[Cicero]

================================== The bike cost 15 pounds. It's worth nothing and it's useless unless the old seat post is removed. That would be money down the drain.

Chronos Engineering (and others presumably) sell a budget range of reamers

- about 14 GBP for one suitable for the OP's requirements:

advantage of the reamer over a rawl bolt is that the reamer can be pre-set, wound in and then used to give a turning motion to the tube. My

1" size is about 8" long and the Chronos one would be about the same. The longest 25mm rawl bolt I can see is only about 4" long and this may be too short even to reach the stuck tube. Rawl bolts are not too useful when using them as metal to metal. If tightened sufficiently to grip there's a danger of expanding the tube in the bike frame which would exacerbate the problem. If it's not tight enough it will just pull out leaving the stuck tube stuck.

I'm well aware of the risk of possible damage to the reamer but it seems a risk worth taking as the first attempt should show if the tube is just mildly gummed up or seriously jammed. The OP apparently bought a 'pig in a poke' and wants to salvage what he can. That's reasonable and in this unusual situation it's worth weighing the cost of a possibly damaged tool against the cost of discarding an otherwise good bike.

Cic.

[Bob Eager]

As previously suggested, the bolt can be replaced by a long piece of studding.

As previously suggested, one expands the wings of the Rawlbolt slightly so that they catch the far end of the stuck tube - the Rawlbolt is posititioned beyond that end. The wings will expand 'near end first' and catch the edge of the stuck tube. No expansion inside that tube.

[Dave Baker]

bought a bike for £15 then spent another £15 on a seat post the old one being hacked off and the residue left in the frame where it can not be easily convinced of the error of its ways.

I can't use the present post without cutting it down and don't want to cut it down. It's worth more than the bike at the moment.

The pedal crank housing prevent pushing the old piece out and it may have some rust or chrome peel or just dirt... whatever holding it in situ.

Anyone ever come across anything like this?

You've had a few suggestions, some of which like an adjustable reamer are non starters. I assume nothing is sticking up out of the outer tube or you would have tried gripping that bit already. Easiest way is probably to grind (dremel with a little burr) or saw a couple of slots in the top inch of the inner tube then with a small cold chisel or screwdriver fold them in to create a flap you can grip with a vice grip. Then tap that up with a hammer and it should all come out.

[The Natural Philosopher]

That's what I did in a similar situation so long ago I can't remember what it was...on!

I remember driving a thin screwdriver between inner and outer tubes to 'pop' the inner away from the outer, and then using wire cutters and chisels to split and lever it all away.

ISTR the outer was a bit buggered.

Hang on tho. This is a bike saddle right?

So undo the retaining bolt completely, and there is a slot at least partway in the outer tube that can be levered apart a bit, or have a bit of hacksaw inserted at an angle to start splitting the inner tube?

Copious amounts of WD40 should help too.

[Clint Sharp]

In message , ":Jerry:" writes

Ahh, I see, I meant attach the washers after you dropped the bar down by fiddling them onto the bar in the crank housing. Probably my bad, it was late.

[geoff]

encounter every few months........ solution is to cut the tube off level with top of frame and then use a hacksaw blade/padsaw to go down inside the tube on 2 oppsite sides, cutting it into 2 pieces...... try not to slice into the frame! Once it's cut, you can knock a screwdrive or whatever down side of tube and they should come loose. Must admit, I've only done it with the alloy seatpins but should work just as well with the steel..... just takes longer!

Geoff