Bicycle Mechanics - Which way to turn the BB cutters? - For chasing (tapping) threads

Hi. I just got a new BB chasing tool, but no instructions. Which way do I turn the cutters for chasing the threads? thanks.

Whichever way would tighten a bb on for that side. If it's marked R.H or L.H, this indicates thread direction... not which side of the bike you put it on.

The same way you thread in the respective bb cups. Remember use plenty of cutting fluid and go 1/2 turn in, 1/4 turn out.

You also want to have both cutters in the BB. The other cutter acts as a guide and lets you cut the threads correctly aligned

The same way you thread in the respective bb cups. Remember use plenty of cutting fluid and go 1/2 turn in, 1/4 turn out.

You also want to have both cutters in the BB. The other cutter acts as a guide and lets you cut the threads correctly aligned

Errm... isn't it the case that you shouldn't use cutting fluid on aluminum?

Umm I'd never cut anything dry.

http://parktool.com/repair/readhowto.asp?id=97

Errm... isn't it the case that you shouldn't use cutting fluid on aluminum?

No.

This one situation where WD40 is useful. It is an adequate to good cutting
fluid for aluminum and if you want to avoid chatter, use some sort of lube
such as WD40. Use any kind of oil in a pinch, bacon grease is another option.
WD40 is not useful for steel or Ti.

This one situation where WD40 is useful. It is an adequate to good cutting
fluid for aluminum and if you want to avoid chatter, use some sort of lube
such as WD40. Use any kind of oil in a pinch, bacon grease is another option.
WD40 is not useful for steel or Ti.

WD40 I *have* used on alum. The times I've used park cutting oil or some other similar viscosity oil on aluminium the cutting/facing tool wouldn't bite and take off any material.

operator and nitropowered: what did you guys use? or what are you doing differently?

I use the park cutting fluid, it works fine for me. That *is* what it is designed for, cutting/tapping/facing operations etc.

Whichever way would tighten a bb on for that side. If it's marked R.H or L.H, this indicates thread direction... not which side of the bike you put it on.

Yabut, if the taps are Park, the fine print on the tap says "Right side of bike" or "left side of bike"

Kerosene is a good cutting/tapping fluid for Al and that's basically what the majority of WD-40 is.

When I was working with aluminum a lot as a fabricator, we used a Beeswax when cutting or band-sawing. I think it was actually sold specifically for that purpose.

Slightly ot- I had the lbs chase the threads on my new frame that was all powdercoated in the bb (steel) and it came back still with powdercoating in the treads. It's must better and the threads feel crisp, but it's still somewhat green (the color) for the most part. Also the sides of the bb, it's been faced like 80-90% around, but there's still a patch of green. I'm assuming (hoping) that there was a slight depression in the side of the bb so rather than keep cutting down to where there wouldn't be any paint left, they just squared it up by taking a minimal amount off.

Anyway, is this typical? I always thought the point of chasing the threads was to remove all the paint. Or is it just mostly to get the threads and bb straightened up to proper depth, etc.?

I always thought the point of chasing the threads was to remove all the paint. Or is it just mostly to get the threads and bb straightened up to proper depth, etc.?
Chasing is done to get the threads clean, smooth and at the proper depth. Facing is done to be sure the opposite bottom bracket (or head tube) faces are flat and parallel. If all that's required is scraping off excess paint, that's fine but often some metal has to be removed too.

Slightly ot- I had the lbs chase the threads on my new frame that was all powdercoated in the bb (steel) and it came back still with powdercoating in the treads. It's must better and the threads feel crisp, but it's still somewhat green (the color) for the most part. Also the sides of the bb, it's been faced like 80-90% around, but there's still a patch of green. I'm assuming (hoping) that there was a slight depression in the side of the bb so rather than keep cutting down to where there wouldn't be any paint left, they just squared it up by taking a minimal amount off.

Anyway, is this typical? I always thought the point of chasing the threads was to remove all the paint. Or is it just mostly to get the threads and bb straightened up to proper depth, etc.?

Facing isn't so important if you're putting in a cartridge bb.