Hey -
There are some other threads with more model-specific thoughts on this. With Loose Screws no longer in business, I'd like to bring up this problem again. I have an old headset with a few rusted allen screws. I am going to try to get the screws out without drilling which I am sure is well-documented elsewhere on here. Does anyone keep a kit for repairs? Something like this:
4,5,6mm kit, 118 pieces of stainless steel bolts, nuts, washers, Bolts, Nuts, and Washers

This kit is more expensive than the kits on Amazon with a variety of sizes beyond what bikes usually accommodate. Any other ideas?

Check the yellow pages for a fastener supply store. I have a great place that's local to me and I can buy a dozen m3 screws at a time if I need to. I bought 250 m2 washers for spokes and they cost me 7$. Fastenal can order you pretty much anything you'd want too and they have stores in a lot of places.

Truthfully, I've never seen a headset with Allen screws, so I'm unable to get a picture of it in my head. As far as busted screw removal, perhaps a machine shop supply vendor, Fastenal, or a place like that would be able to supply one, or a good hardware store. My dad always had those kits, but I never asked where he got them. I just busted the screws and he got 'em out.

I've broken a few bolts off in modern stems and seat post clamps, and I used a hacksaw blade to get in there and "grip" the threads and back out the pieces. These were NOT on rusted bolts, though. Good luck in your endeavor, and welcome to the forum. Some of the best wrenches are here.

Clearly, I need to work on my bike terminology. I meant the stem, not the headset. I will try to find a fastener supply store. I live in Chicago, must be one around here.

And thank you for the instant help. I have been reading for a while on here. I have a lot to learn.

You'd have better luck at a LBS that sells used bikes or a bike cooperative for parts like that. If the bolts have a 6mm thread, use a socket wrench allen, more leverage.

I got tired of running down to the hardware store buying small 5 & 6mm bolts & nuts and paying through the nose for them, I found this place and have spent the last year stocking up on SS hardware for a fraction of the cost I was paying. Any order over $15 and shipping is free, they will give you a 10% off coupon with your first order that so far still works every time I buy something. I have got metric hardware from 2mm though 8mm in a ton of lengths in stock at all times now. Hex Nut - Carriage Bolt - Brass Fasteners - Fastener Supply - Threaded Inserts | Albany County Fasteners

Glenn

Here's one posted in Velobase.......VeloBase.com - Component: Mavic 315

..the Home Depot here has a selection of metric hex head socket cap machine screws in 4,5,6 in various lengths that is quite impressive.

There are quite a few drawers in the section where they are at, so you might want to ask for help on your first visit.


They also sell a set of metric taps and dies for thread restoration that covers 4, 5, 6, and 7 mm metric. Different location, over in tools.

Online there is McMaster-Carr. They have almost anything.

I buy them in a box of 100 at a local nut and bolt store.. i keep a variety of lengths.