Current Projects chat and miscellany

4mm is nothing, get ya stretch on.

Has anyone successfully “dimpled” a seat tube to clear a slightly bigger tyre?

Want to run 25c gp4000 (measure closer to 27) on my donohue but JUST rubs on seat tube.

What do we reckon?

Wider rims which will lower the profile of the tyre?

Yeah, but hammers are cheap.

spin the wheel over some sandpaper... or an older tyre...

Get a hammer and start hitting the frame. I’m pretty sure the effect will be great!

Dafuq do I do now?

Drilled a hole to tap threads for mudguards. Silly me drilled a hole that was too small. Tap broke in frame. Can't get it out. Have tried everything I could think of.. any ideas?

The tip was already through the other side when it broke. I managed to break it off quite far into the dropout, so the there is only material from the tap about half way (maybe 2/3rds) through the hole.

new frame

but in all seriousness, I guess you tried drilling it out?

Could try these if you can find one small enough?

Gunna be tricky though, what size is the tap?

You’d need to drill a little starter hole in the bit of broken off metal...

Maybe just drilling it out (as rodolpho says) would be your best bet

You can definitely drill it out. Also with tapping, there will be a specified drill bit to the tap e.g 5mm for m6x1 tap and use plenty of cutting grease

How much of the tap is poking through ?
Couple of mm ?

Mole grips clamped onto the end and some gentle twisting with a good squirt of lube....... you might be able to wind it through.
Failing that as the others, drill out, or try an extractor.
If no access to any of the tools then either try a local metal fabricators or back street garage, or even your local Bike shop who most likely have the tools.

Brute force cheap choice.
Smash it through with a drift and big hammer.
Re drill hole and go up a size with tap.
Is it a nice frame ?

Cheers for input

Haha yup i've tried drilling it out with same size bit, and much smaller bit to create a starter hole, but either the bit wont grab/cut any metal, or the bits break. Makes sense as the taps are meant to be harder than everything else in order to cut threads, right? Any specific metal drill bit i should be using? A drill press would help im sure. (ive been using a hand held)

@MCamb @Norfolkbound I used an M5x0.8 tap and a 4mm drill bit. Guess a 4.5mm bit had been better? Lubrication was used.
What are those things in the picture called, that an extractor?

@853Superfly There is no longer any tap sticking out. I tried mole grips when there was a bit (maybe about 4mm), but there was no chance. Also tried brute force. Sharpened a philips screwdriver, rested the inside of the dropout against solid metal, and hit repeatedly with a big hammer. Managed to splinter the tap a little bit, but theres still lots left. Frame is an old Ti 26" mtb. Huge sentimental value, but nothing super fancy/expensive. Pretty bunged up/diy in the first place.

Going from 4mm to m5 or 5mm to m6 hasnt been an issue before in steel and alu. Titanium is harder than i thought! Cant really go up to m6 thread either, as there is no room for a larger hole in the mudguard strut.

I thought about using a hacksaw to cut a line from the outside edge of the dropout, in towards the hole, hoping it would free some room for the tap to budge. Buuuut after a few seconds of contemplation i realized that's pretty overkill and very destructive.

The zip tie solution is actually amazingly sturdy, and the guard sits very well as is. Mostly just the thought of it that bugs me.

Have someone trephine it out ?

https://a-zortho.com/media/k2/items

I used an M5x0.8 tap and a 4mm drill bit. Guess a 4.5mm bit had been better?

4.2mm is the usual tap drill size for M5×0.8, using a 4mm was always going to break the tap unless you were trying to put a thread in some cheddar. It's really hard to apply pure torque to a tap by hand and any eccentric force will easily snap a small one even if the pilot hole is the right size, so a drill press with a tap follower in the chuck would have helped, but not enough to get you past the problem of trying to tap Ti (as you have discovered, and as everybody else already knew, an absolute bastard to cut) in an undersized hole. If you ever get the remains of the tap out, you might as well go to 4.5mm on the pilot, it will reduce the cutting force considerably and having the minor diameter of the finished thread oversized will still leave sufficient strength in this application.

Bruce Whitham is the god of thread repair, you might learn something useful from his Getter Out playlist https://www.youtube.com/channel/UC6HG4kXPSgb1Bhx6CY9e6iw/playlists

The chemical method seems to be Ferric Chloride, which you should be able to buy from Maplin as it is a common etchant for PCBs. It dissolves steel but not Ti

Only other soloution i have involves a workshop set up with a pillar drill.

If you can't get a drill into the Tap, it's hard steel so may well break and blunt cheap drill bits, a trick i learnt for drilling larger holes was to use a masonary bit on a very slow rpm and it nibbles it way through rather than cut's through.
Would need a pillar drill.

Ferric Chloride sounds exciting........ soooo if some of that ended up on say.... the roof/bonnet of a car, as long as it's steel it would eat through.

soooo if some of that ended up on say.... the roof/bonnet of a car, as long as it's steel it would eat through.

You'd have to scrape through the paint to bare metal first. You need about 6 times the mass of anhydrous ferric chloride as the amount of iron you want to dissolve.

Soo a frozen shit sausage up the tailpipe, allowed to defrost overnight which would then spray everything behind the car when the engine is started would be easier and more dramatic.
Ferric Chloride sounds very focussed in it's use :) the random things you learn here :)

Back to business and jammed Taps.
If you have mullered both now broken ends of the Tap, these could help grind in a divot to help restart drilling, give the drill tip a good area to bite into.
Little die-grinder bits from dremel. Never used them on tool steel so unsure if you could actually nibble your way through a Tap with them.

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Good info, thanks a lot. I could spend hours watching Bruce's channel!

I've sort of lost hope in drilling it out tbh. The Ferric Chloride option seems very appealing, and have found some decent youtube videos describing all the details and precautions.

Life's too short 853 superfly. Fill the hole with filler and buy a pair of pclips!

Don't talk to me about effing p-clips :)
Like rocking horse poo trying to find them things :)

Good shout! One of those in a drill press seems plausible.

:) @ianjchip
In the nicest way possible, go do one :)

This thread thrives on oddballs throwing out weird ideas to get around issues :)

t0-ster good luck ! i am out of practical ideas without access to a workshop, and i have learnt new things from @mdcc_tester along the way viv la forum :)

Biltema has p-clips in their auto parts section.. just saying.