Replacing screws

Post by **winger300** » Thu Jan 29, 2004 12:49 pm

I had to drill the screws holding my voltage regulator in order to remove it. As always the screw heads were rusted up and rounded off.

I replaced them using brake-boss bolts intended for Mountain bikes. They have a hex-key head which in my experience are much better than screws.

Wouldn't it be a good idea to replace most screw-headed bolts with allen bolts? especially those darn brake drum screws!

Post by **rayofleamington** » Thu Jan 29, 2004 12:53 pm

those darn brake drum screws

If they are chewed up I tend to throw them away. I've never had a drum willingly come off anyway. When the wheel is tightened on it's superfluous anyway.

Post by **salty_monk** » Thu Jan 29, 2004 12:57 pm

Try Modern Screws in Bexley. They stock most things or can get most things subject to a MOQ.

Maybe you can become the MMOC socket head (hex key) bolt supplier...

Post by **brixtonmorris** » Sat Jan 31, 2004 9:30 am

not always a good idea. they are very tough. it was a fashion on old english motorbikes. on my triumphs i found that they were used to replace the screws that hold the side covers on to the engine. the allen key has a lot of leverage and the bolt being so tough that the threads in the ali got striped. and even worse the bose for the threads split in half. all had to be refilled will ali. redrilled and re taped. socket bolts did not go back on the bike. The soft metal of screw heads will fail before soft threads, protecting them. my modern ducati has realy soft ali bolts, almost one use and they need to be renewed. the shape of the head fails
they are ali not steel to save wieght, and it also saves on manufacturing cost
better have the screw heads fail the the threads on expensive parts fail. it was a lot of spicilised work to rebuild those triumph crank cases. most old triumphs have this problem due to cap heads.
i cant recall any ali threads on a morris though.

Post by **les** » Sat Jan 31, 2004 9:04 pm

I like cap headed screws, they look neat. I must say I've not had trouble with threads stripping, surely an allen key affords less leverage than your average spanner, whatever the metal. I think these screws are best when screwed into something, rather than used with a nut.

Post by **Matt** » Sat Jan 31, 2004 9:17 pm

Surely it also depends on the size of the bolt........

Post by **brixtonmorris** » Thu Feb 05, 2004 12:08 pm

hey les, spanners are not used on screws

Post by **Peetee** » Thu Feb 05, 2004 1:12 pm

Wouldn't it be a good idea to replace most screw-headed bolts with allen bolts? especially those darn brake drum screws

NO!
I have a lot of experience with building and repairing bikes (I have six, designed one and built them all - including the wheels) The allen screws you mention are probably M5 thread with a 5mm allen head. These cannot be subjected to much torque at all without damaging the internal hex surfaces or the spanners because they are usually not hardened. If they become rusty you would be better off trying to remove a normal head nut. The minimum you should consider is a hardened bolt with a 6mm hex.

Post by **Cam** » Thu Feb 05, 2004 1:35 pm

hey les, spanners are not used on screws

Unless they are hex-headed screws (as found on most jubilee clips).

NO!
I have a lot of experience with building and repairing bikes (I have six, designed one and built them all - including the wheels) The allen screws you mention are probably M5 thread with a 5mm allen head. These cannot be subjected to much torque at all without damaging the internal hex surfaces or the spanners because they are usually not hardened. If they become rusty you would be better off trying to remove a normal head nut. The minimum you should consider is a hardened bolt with a 6mm hex.

I recently had a similar problem with a VW Jetta crank pulley (held on with allen headed bolts). Virtually impossible to undo without rounding the heads off. If proper hex-headed (normal) bolts (or set-screws) were used it would have been easy!

Post by **les** » Thu Feb 05, 2004 8:10 pm

A screw has the thread up to the head, a bolt is only threaded so far up. Obviously not wood screws!

Post by **Peetee** » Thu Feb 05, 2004 10:28 pm

A screw has the thread up to the head, a bolt is only threaded so far up. Obviously not wood screws

Surely the difference is that a bolt has a linear shaft and a screw is tapered?

Post by **rayofleamington** » Thu Feb 05, 2004 10:38 pm

A screw has the thread up to the head, a bolt is only threaded so far up.

That's certainly the technical definition. Of course not everyone uses the technical definition, and the general public are confused because wood screws don't fit the rules.

Post by **brixtonmorris** » Fri Feb 06, 2004 10:56 am

there is always "the lead screw"

Post by **57traveller** » Fri Feb 06, 2004 3:13 pm

Les is correct - even a hex. head bolt is a set screw once the thread extends to the head. It gets complicated and sometimes confusing!
Then there are the various types of screws, machine screws - pan head, socket head (Allen), countersunk etc.

Some types of couplings have tapered bolts, however the threads are parallel.

"Lead screw" yes on a metal turning lathe?

Post by **les** » Fri Feb 06, 2004 9:31 pm

Here's an old one! (headline in local paper) Nut screws washers and bolts.

Post by **brixtonmorris** » Sat Feb 07, 2004 8:03 am

never heard that one before Les lol

Post by **rayofleamington** » Sat Feb 07, 2004 3:30 pm

I guess that was a Vandal caught at the laundrette who escaped...

Post by **brixtonmorris** » Sun Feb 08, 2004 3:40 pm

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 2458131400

Post by **Cam** » Sun Feb 08, 2004 4:33 pm

You speak the truth O wise one....................

Post by **brixtonmorris** » Sun Feb 08, 2004 7:40 pm

hi cam