Just been think about a silly project i'm in the middle of, it's kinda supposed to be a retro-ish old tt bike. I've come across a few bikes I am hoping to copy parts of and both of them have internal cables, the frame my bike is a rubbish hi-ten lugged steel frame. I was just wondering if anyone had done this before and if it is indeed possible and if so how. I've included a picture of the frame if its any help.

Thanks

running the cable through the TT is so much easier , done to the tube itself, before putting it into the frame..
so the tube ends are available to fit things through.

that being said , I'd skip the PIA of cable replacements in that style of feature .

Shouldn't be too hard, but you'd have to go with a full-length housing, making your brake spongier.

Just trim off the cable stops (more and more patience required as you get closer to flush with the tube) and drill holes where appropriate. If you run the rear brake from the left, do the hole on the right for a smoother path for the cable.

I'd drill straight into the tube, then angle the drill to about halfway to the cable's proposed angle, clean it up with a rat-tail file (don't leave sharp edges; file them at 90° to the tube wall), insert a bit of housing-sized rod, and tweak it to make a dent and bulge. Pretty easy.

Internal gear cables, that'd be a challenge.

I don't know that I would just drill holes, without some reinforcement, most likely via brazing Frambuilder's forum may be helpful. I think options recommended include brazing a tube in side the top tube or useing special fittings. There is also on and off chatter about interanal cables leading to rust and failure. I havn't seen that on my Miyata, but I do baby it.

I've seen plenty of frames with holes just as I describe for an internally routed rear brake.

Shouldn't be anything close to a concern on a hi-ten frame given the thicker tube walls; cheap frames are often stiffer than nice ones, and I'm sure this one is plenty strong enough. Hell, I've seen the same done to ally bars without issue; that's verging on sketchy.

If I was going to go to all the trouble of breaking out the oxy torch, I'd only bother with a nicer frame, and I'd make it a split housing setup.

Thanks for the replies and I will hopefully get round to giving it a try at some point.