The bolt in the SFN seized, and when I came to undo it it sheared off level with the top of the steerer tube.

I took the forks to the LBS and he mentioned that he would bash the SFN back up out of the top of the steerer, but this concerns me as the steerer is aluminium (Rebas), and I am worried that this may damage the steerer tube, should I be concerned and go and retrieve my forks?

I’d be worried!

Standard approach is just to bash it down further and put a new one on top 🙂

Or you could drill out the middle and it’ll fall apart.

bash down not up. either all the way through or just low enough for the new one

do check that the internal diameter of the steerer tube doesn’t reduce towards the bottom if you try the ‘bash it all the way through’ approach. 😳

Once distorted the steerer on some Rebas simply by overtightening one of those Hope Head Doctor things so I’d be mildy concerned about [ quote]bash the SFN back up out of the top of the steerer [ /quote]

Indeed, I think the steerer tapers in toward the base so I could tap it down but not out. I think I may go and retrieve the forks.

I drill ’em, takes no time really but then yours has a bolt stuck in it which might not help. Wouldn’t bash it up, no way, it’s basically a barb.

bash down not up

think of the children!!! no but really, who T.F. would bash it up?

I’d probably bash it up if the steerer is tapered towards the bottom. it’s more likely to deform rather than gouge if you do it quick and hard enough.

I have the forks back, and think I will either just bash it down out the way or try and drill it out. Drilling may be more difficult as NW mentioned though as it has the bolt seized in it.

drill down beside the bolt.

Be eaiser if you have a vice and pillar drill but as long as you’re careful and the steerer is in a vice a hand drill should be fine.

The bolt is Alu I think (galvanic corrosion?), therefore it should be quite easy to drill it out?

I can’t imagine that gripping the bolt nice and tight with a pair of Molgrips wouldn’t shift it, then +1 for the drill out option.

I’ve removed a few on mine and other peoples. I prefer to drill them out using ever increasing bits. once they start to give they fall out quite quickly. Don’t rush it.

drilling is just so messy though and you end up with bits of metal swarf everywhere and in your bearings.

are you going to use a nice steel bolt in future?
if you’re that bothered about the weight, just take the bolt out once you’ve tightened up the stem – it’s not doing anything.

Oh, I was assuming a steel bolt but if it’s an alu one then back to plan a, drilling. Also been assuming that you or the shop have made a decent attempt at unsticking it with quality penetrating oil, maybe a little heat, and molgrips or a stud extractor? (depends how much bolt is left)

brakes – Member

drilling is just so messy though and you end up with bits of metal swarf everywhere and in your bearings.

If you do it in the bike, possibly (though it shouldn’t get anywhere near the bearings even then).

Drill out the central bit that holds the two ‘SFN washers’ then it’s pretty easy to prise out the two of them seperately.

Damaging the shaft is a very real concern when bashing your nuts out.

If you get a flat blade screw driver and tap a few of the barb bits they tend to fall off or deform. You don’t have to do it that hard to deform them, it’ll just drop out when you knackered enough of them.

I bashed one out last night….guffaw, guffaw

seriously though, old seat post through the top of the steerer and rubber mallet bashing the nuts out the bottom combo worked a treat – new nut went in absolutly fine

no damage to the steerer or the forks, the star nuts will deform before the steerer!

If you get a flat blade screw driver and tap a few of the barb bits they tend to fall off or deform

that’s a good point actually – I’ve knackered a SFN before trying to install it with a screwdriver

spray lots of plusgas clickyon the seized bolt and leave overnight. then with a set of molegrips undo the sheared off bolt. or better still with a dremel grind a slot in the top of the bolt and use a screw driver to remove.

i would flatten as much as you can the left over bolt, then centre punch the bolt as near the middle as you can then just drill it out, by centre punching the bolt the drill will tend to follow the bolt instead of pushing off, ive drilled out quite a few and if its an alluminium bolt it should be easy lol

deform the tabs on the SFN using several, well-placed taps with a flat blade screwdriver and hammer and then thin nose pliers if needed, which will cause it to lose grip on the I.D. of the steerer tube, and it will easily come out with minimal force

don’t ever want to “bash it up” because the wings of the SFN will remove a substantial amount of aluminium alloy from the wall thickness of the steerer tube

That tube has that wall thickness for a reason 😉

Just tap it down and fit a new one above it ,

I got one stuck so badly once on the way down the steerer, it’s still there. The force of 4 men couldn’t get it through, pretty sure the metals have just bonded at this point 😛

Using a piece of steel pipe or some old flat bars and a decent lump hammer you can knock a SFN out no problem. With using pipe to knock it out you are applying the force to the wings not the threaded centre so they don’t splay out and dig in. You might take a fraction of material with it but it won’t ruin your steerer. It will be designed with a factor of safety of about 4, if you lose some material it might go down to about a FOS 3.5 which is still 3.5 times the yield strength.
If in doubt though knock it down.

if you lose some material it might go down to about a FOS 3.5

Nobody died in the making of this thread…

Drill it out till the two halves of the SFN are separated, then twist them to the side, fold them, and remove them.

A mate of mine didn’t loose his face after a corroded steerer failed because of an old SFN at Morzine, but now I’m all about not mixing different metals there.

🙂