i want to file a little of the top of the fork dropout away, so that the wheel sits a little higher in it, about 3-4mm or so. what file should i use?

i suggest something stronger than a nail file.

round file. Make sure you do it evenly so the wheel stays straight othewise you might have problems obviously. 3-4mm seems like a lot why do you want it sit higher in fork specifically. Honestly I wouldn't bother.

use a dremel, but be careful with this. why are you doing it? for aesthetic purposes? by lowering the front end, you're going to slightly change the handling of the bike.

careful that there's enough meat left. that's an area on the bike i wouldn't want to screw too much with.

maybe 3mm. there's plenty meat there. will change head angle approx 0.2°. just want it tighter is all

Why?

why not? boredom is a brutal temptress.

Only use a dremel or other roto tool if you are sure you can control the thing. I used to carve Magnesium speed plane parts w a dremel because I was in HS and did not have the right tools. The amount of chatter you will get with anything other than a disposable abrasive drum is scary and will ruin your roto tool's bearings very quickly. Assuming the dropout is alum, the abrasive head will clog very quickly and you'll have to get another, and another, so don't bother w the stone stuff. If it is steel, the abrasive will last longer. Look out for heat build up. Not sure if they make a sanding drum that is small enought in dia for the dropout. If I had to do it, I will use a good rat tail file, and just burn the elbow grease.

Because.

I suppose. I guess I just don't see the point in going out of one's way to reduce a bike's practicality.

I have absolutely no experience with metal worikng, but I have heard that when cutting steel, you need to use a low speed. Otherwise, it will heat up and harden.
...in case you didn't already know.

Don't believe everything you hear

Poopn, milling and turning steel since 1983(but not anymore), cow

yo eddie
just remember that you are now restricting the max tire size in the fork. Is this a clearance thing?

also you'll have that ugly extra 3mm of fork dropout sticking out the bottom of the bolts. Do you really think you'll notice the .2º? I'd say if your really that bored you should clean your chain. But thats just me so do what you want to your bike.

yeah, but i've run 23mm tires exclusively for about ten years now so i'm cool with that.
and yeah it's a clearance thing. just want to close that gap a little. minimal clearance track forks give me a *****. and i won't screw it up - i'm good with this sort of thing

edit: chain's clean

I have done with with steel and aluminum forks.
I first mark the desired height change with a good score line (not with a marker)
I then used a drill bit of the same width of the dropout and gently go back and forth on a medium speed and work my way up to the mark. Has worked for me and it leaves the nice round end for the axle to rest in.

bryan

i've done this before but with a hand file. the axle was a little too gerthy for the fork dropout so i filed it all around to open it up a little more and it worked perfectly.

I would be reluctant to use a power tool. Fork dropouts tend to be made out of a relatively soft carbon steel, so hand filing doesn't take long. So you don't mess up the alignment or have to fix a weird-looking slot, I'd recommend getting a non-tapered large chainsaw chain file. These are round files that cut rapidly but don't have a taper to them (which helps keep the dropout slot even). They are long enough that you can guide the file through one dropout while filing the other one. Cutting that much metal won't keep you busy for all that long -- 10 minutes at most should do it.

I'd do it even faster...just line everything up right and shoot a hole through both dropouts at once. A .38 will work for smaller axles, a .44 for the larger ones. Be sure to use adequate eye protection and make sure that there's 40 feet of dirt on the other side of the fork.