SFC1000 foot rest mount

[SkinnyPinny]

Hi all,
Undoing the foot rest mounting plates,
These bolts are well and truly stuck.
Before I go to town and do some damage,
Is there any reason to think that this is anything other than std thread, not left hand ? See attached image.
Using an impact wrench, I tried plusgas type spray dismantles and dripped a mix of acetone and oil,
Thanks in advance,
Stuart

 

[andre g]

It is standard thread, I think M 10. The issue is that these countersank screws just use smaller Inbus keys, 6mm in that case and the screw can easily damaged by high force.

 

[sfcpiet]

The fact that they're countersunk make them so stubborn, just so much surface area that offers cohesion. A little corrosion makes it even worse. The small hex for the socket doesn't help matters at all, that is quickly rounded when applying the required torque.

Hit the bolt with a centre punch at an angle on the top surface in the loosening direction, normal RH thread. A couple of wallops with a hammer on the socket may help to break the initial grip, but that often ruins the socket, unless you have a copper or lead hammer. Maybe you'll find an old, rusty socket that you can sacrifice in grandpas old tool box...

You'll probably need a new bolt no matter how you manage to remove it.

piet

 

[SkinnyPinny]

Thanks Piet, not worried once the bolt is out, it will be replaced with a new one.
Currently soaking but I’ll give it a go with a centre punch,
I was surprised that my impact wrench didn’t shift it,
Cheers,
Stuart

 

[sfcpiet]

A 6mm hex doesn't offer enough leverage, not even for a rattle gun. It would just round out the hex. An old-fashioned impact driver (the type that requires a hammer) could do the trick though.

piet

 

[andre g]

At work we often used M8 countersunk screws with an 5 mm socket. When our tecnicans had problems to get the screws out, they used a Torx socket and hammered the socket in the screw and could dismount it. Or us a drill to get it out.

 

[pf1]

Crude but I use the impact driver and just hammer larger torx bits into them until they give in.

 

[ozijotati]

I had exactly the same issue with an sfc 1000 that I owned. Ended up drilling in to the centre of the bolt and progressively increasing the drill size. Ended up with the countersunk head drilled off and then just unscrewed the remainder by hand. Piet is correct in saying that it’s the countersunk head that’s the problem. Upon assembly I used anti siege on the countersink and had no issues later on. Good luck
Tom

 

[IAG]

The fact that they're countersunk make them so stubborn, just so much surface area that offers cohesion. A little corrosion makes it even worse. The small hex for the socket doesn't help matters at all, that is quickly rounded when applying the required torque.

Hit the bolt with a centre punch at an angle on the top surface in the loosening direction, normal RH thread. A couple of wallops with a hammer on the socket may help to break the initial grip, but that often ruins the socket, unless you have a copper or lead hammer. Maybe you'll find an old, rusty socket that you can sacrifice in grandpas old tool box...

You'll probably need a new bolt no matter how you manage to remove it.

piet

Agree w/ the punch but I've found a brass drift works as well & the soft brass won't damage the fastener. My 2p worth-

 

[piranha-bro2]

Junk the bolt - drilling as per Tom is the quickest way to get it off.

 

[Vince]

Found similar with countersunk large-headed fixings on a Steel Fire Door frame once. Dug out the Hammer activated Screw punch I hadn't used since I stopped trying to remove Japanese slotted-headed case bolts in the 1970s. Still a great tool for soft headed siper tight fixings. Everything I own got stainless Allen heads ASAP.

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[piranha-bro2]

Yep, got the old classic Japanese impact set in the nice blue metal box when i got the DT2 Yammy. Not a choice ... obligatory. Still got it and it comes in handy now and then. It's a clever system - impact to shock the mongrel and a bit of a simultaneous twist in the right direction. Far smarter is to ditch Philips heads and go 'modern' alternatives like cap screws!

 

[Andy]

The torx bit tip is gold, used it a couple of times now. My old boss had a set of reverse drill bits that were useful, if you had to drill a head off, often the drill would grab and unwind the problem screw. Especially if you’d already smacked it with a hammer a few times to unfreeze it

 

[piranha-bro2]

Yeah, I wouldn't mind a set of those reverse drill bits. Generally a fookt bolt head means once the head's off the thread is actually free. Busted studs and bolts with seized threads is another story. If I can, I like to fit the part onto the lathe bed and use a mill to get a flat surface, then a centre drill as cose as dead centre as poss, then increase drill bit sizes until the thread looks like a helicoil. It's very satisfying when you succeed.

 

[Laverdalothar]

I remember to having had the same issues, soacking it with WD40 and other stuff, heat and cooling applied and at some point, it gave up. Took a while though...