My cable guide on bottom bracket is a press on type and doesn't have a screw.
Looked around the 'net for a replacement but all of them have a screw.
This is for an older Black Diamond, "Ascent" model mountain bike that I just got and need to get in shape.
thanks

What's wrong with the current one? I assume it's damaged in some way or you wouldn't need to replace it.

Assuming we're referring to the type that go under the BB shell, I find that most cable guides tend to stay put under cable tension only - one of my bikes doesn't even have the screw holding it on.

The cable guide is worn down and cable is starting to cut into the metal of the BB.

Wow, that's not something I've seen before, has the bike been ridden through a lot of very abrasive mud or something, or has it just done a lot of miles?

My suggestion would be to simply use any old cable guide, and let the cable tension hold it against the bottom of the BB. As I said, this works for me.

I just got this bike second hand and it looks like it's got a lot of miles on it.
Thanks for the suggestion.

If you have problems with the cable guide moving you may be able to make it stay put by using a dab of rubber cement to hold it in place. If you apply the cement to one surface and press it into place before it dries it will hold fairly securely but be able to be peeled off should you need to. Spray-on artist's adhesive may also work.

I imagine that using some double sided sticky tape (carpet tape?) might hold better than rubber cement. it doesn't need to be all that strong of a hold, the cable themselves hold the guide in place.

A little adhesive will keep the guide in place when you're changing cables.

And FWIW, cables rubbing directly on the BBshell isn't a huge problem, either. Many manufacturers used to do this, either by filing a channel for the cable, brazing loops or tunnels onto the shell to guide the cable, or having channels cast into the shell itself as part of the shell design.