Boring out a pushbike saddle tube.

[winchman]

The correct tool is like an end mill but has a chamfer on the end from memory Wylcut swift make them
https://www.ukweblist.com/UK/C96B250657/Wylcut-Swift-(Cutting-Tools)-Ltd
Its a seat post reamer, The machine is basically a motor with a reduction box mounted horizontally with the cutter on a shaft about 12-18" long.
Trying to think who in the UK makes bikes on a big scale as they will have one, the use them to clean the seat tube to remove any paint scabs etc before assembly but they would cut a seat post out

 

[mtt.tr]

Id make a counter bore, its self guiding

Id just use mild steel and weld on a hss cutter

Send me dimensions if you are not in a rush im happy to make a tool more for the crack.

 

[angellonewolf]

If you have an old steel stem that would fit then you could cut a set of teeth at the end then a hole through the other end and insert a tommy bar and hand ream it out as it's ally.

i would have thought this sounds like a great idea if you got a steel post the right size cut teeth and you could even weld a bar on the end and attach to a drill ?

 

[Sean]

Hacksaw blade, wd 40 a couple of beers and something to watch on netflix.
Just cut it so its almost through in a couple of places then curl it in with a long screwdriver as a wedge.

Itll take time but its not like your in a rush is it?

 

[james butler]

if you know the correct size id could you make a bar the similar id as the current size and fit a cutting bit to the end then you can drive it like a broach down the tube until you've cut a groove all the way through one side a bit like a keyway broach.
then you could collapse the old seat tube in on itself

 

[stuvy]

It doesn’t have the bottle cage bolts going into the seat tube?

 

[jsf55]

I would have a crack at a 10mm hole in the bottom bracket, which won't significantly weaken the frame and try tapping it out with a long punch, remember with a lot of these tubes they are thinned in the middle for lightness

 

[bigegg]

It doesn’t have the bottle cage bolts going into the seat tube?

I though that!
But i've taken them out. The top one was skewed slightly where the seatpost had been hammered down against it.

 

[bigegg]

So...
I made a thing.
M8 rod, connector nut,a standard nut, old 14mm socket (20mm OD), a broken 5mm drill bit, and some surreptitious blobs of 2.4mm stick weld.



The annular cutter will still be usable for its regular job (cutting holes for conduit), and the arbors are interchangeable so the extended one can be used on any of the various sizes saws i have.

The pilot is also perfect if i i have to enlarge a 20mm hole in a backbox to 25mm

The offending article:

 

[mtt.tr]

Well done. Any damage to the frame?

 

[bigegg]

Well done. Any damage to the frame?

Not that i can see.
Marks, yes, but no big gouges.
I've got some flapdiscs with a 1/4"-20 thread, so i'll make a long arbor and give the inside a polish.

I can't bring myself to fork out for a reamer.

(I wonder if the bike charity has one. )

 

[winchman]

I wonder if this would have worked? Got me out of the brown stuff a few times, I use mine for bike head races and fork seals works very well.

https://www.ebay.co.uk/itm/Inner-Be...=282461490709b4517f11044b492e8c2199553c338a51

 

[mtt.tr]

I wonder if this would have worked? Got me out of the brown stuff a few times, I use mine for bike head races and fork seals works very well.

https://www.ebay.co.uk/itm/Inner-Bearing-Puller-Set-Remover-Slide-Hammer-Internal-Kit-8-32mm-9pc-Blind-Hole/282461490709?epid=24027197866&_trkparms=ispr=1&hash=item41c4044e15:g:mi0AAOSwyQtVkkJk&enc=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&checksum=282461490709b4517f11044b492e8c2199553c338a51

I make those as and when i need them, they are brilliant.

 

[bigegg]

I wonder if this would have worked? Got me out of the brown stuff a few times, I use mine for bike head races and fork seals works very well.

https://www.ebay.co.uk/itm/Inner-Bearing-Puller-Set-Remover-Slide-Hammer-Internal-Kit-8-32mm-9pc-Blind-Hole/282461490709?epid=24027197866&_trkparms=ispr=1&hash=item41c4044e15:g:mi0AAOSwyQtVkkJk&enc=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&checksum=282461490709b4517f11044b492e8c2199553c338a51

I have a home made slide hammer.
Thats a nice looking kit though.
Added to my "wishlist".

 

[Shox Dr]

A bit late to the party. Firstly, are you sure that wasnt a strengthener?
Its out now, so...

secondly, depth of seat post is dependent on frame type. You cannot use 3"/75mm or 90mm as a guide from the top of the downtube.

It needs to be inserted 3" past the first tube intersection. A problem if you use a seatpost that uses shims. It will have no support at the end of the tube, even if its past the first intersection.

 

[bigegg]

A bit late to the party. Firstly, are you sure that wasnt a strengthener?.

The other Paragon I have (a '91 model - same frame, different paint, different shifters, different forks, but everything else identical) doesn't have a strengthener.
If it *was* a strengthener, then the inner bore was <22mm, so it wouldn't have taken any "adult" size seat post?

 

[Shox Dr]

The other Paragon I have (a '91 model - same frame, different paint, different shifters, different forks, but everything else identical) doesn't have a strengthener.
If it *was* a strengthener, then the inner bore was <22mm, so it wouldn't have taken any "adult" size seat post?

When that frame was built, USE seatposts were 22mm. You used [no pun] a shim to fit your frame. There were plenty of people fitting them to frames with the first intersection lower than 3" from the top of the seat tube. Because the seat pist didnt have ant support lower down it would break or bend the seat tube above that first weldment. It may have been a retro fit.

 

[jsf55]

Was it a straight seat pin or one with a built in clamp ? probably find it's old skool 7/8ths pin

 

[Gareth J]

So...
I made a thing.
M8 rod, connector nut,a standard nut, old 14mm socket (20mm OD), a broken 5mm drill bit, and some surreptitious blobs of 2.4mm stick weld.
View attachment 233279
View attachment 233280

The annular cutter will still be usable for its regular job (cutting holes for conduit), and the arbors are interchangeable so the extended one can be used on any of the various sizes saws i have.

The pilot is also perfect if i i have to enlarge a 20mm hole in a backbox to 25mm

The offending article:
View attachment 233281

That "thing" is exactly what I was trying to describe! Glad it worked out

 

[bigegg]

When that frame was built, USE seatposts were 22mm. You used [no pun] a shim to fit your frame. There were plenty of people fitting them to frames with the first intersection lower than 3" from the top of the seat tube. Because the seat pist didnt have ant support lower down it would break or bend the seat tube above that first weldment. It may have been a retro fit.

Oh....
Maybe.