duanedr 

I'm putting the finishing machining touches on a gravel bike that will take a 31.6 dropper - hence the two binders. Droppers like big bands of low-pressure clamping. I was able to get the seat tube reamed and slotted yesterday and then as I was going around chasing all of the threaded bits, this happened! It was time to walk the dogs, so I took a picture and sent it to a neighbor. He and his wife are accomplished cyclists and we regularly share our projects and help each other. A couple hours later, he came over with a little bourbon and his Phil Wood shot glasses and we extracted it with no damage.

A bit about this bike:
This bike has ovalized tubes for top, down and seat tube, s-bend chainstays and s-bend flattened seat stays. It's a little like a homemade Max tube set. I was testing ovalizing tubes on the Femco 3T arbor press I restored. I was pleasantly surprised that I was able to get really nice ovalization with minimal tooling and only a bit of fiddling. The mitering was a bit trickier because tube blocks won't sit as close to the end when using the mill, so the mitering has to be done by hand.

Other details 86.5 T47 BB, Syntace through-axle in the rear, tapered head tube, 2x eTAP drivetrain and flat mount brakes. With the curved stays, it will take a 45mm rear tire with 5mm of clearance each side - which is about as close as I want to go. The chainstays are heat treated so, I'm hesitant to add dimples. Most of the time, I'll have 32mm on it with fenders.

I'll post up more when it's done and the finish work has been completed. There is still work needed on the fillets and it needs bridges and rear hose braze ons. Then to make a segmented fork. Last I checked tapered steerer tubes were hard to find.

20221029_222903180_iOS by Duane Draper, on Flickr

unterhausen

That's probably best case for a tap breakage. I have found they usually happen when I push sideways on the tap.

Worst case was when I was tapping a hole in the side of my Bridgeport and the tap broke off flush with the surface. Now that I think of it, I might have been able to get to it from the inside of the column, but I ordered tap extracters from Mcmaster and had it out the next day. I used to follow some guy that ran a business doing wire edm extraction of taps. I'm not sure a bike frame would be worth it. I'm also not sure it could be done sideways on the side of a bridgeport.

duanedr 

Yes, the tap had to flex a tiny bit to get the handle past the seat stay on the other side and I knew as I attempted the next turn that my toes were dangling dangerously over the edge. Sure enough...

I have a 3-prong extractor, but this was a 4-flute tap. My neighbor brought his set (with bourbon) but those work much better when the tap breaks off flat. In this case, there was enough poking out that vice grips got ahold of the tip and could turn it and bring it through. That tap had done a couple dozen or so frames, forks and stems worth of bosses and binders. It lived a good, purpose-filled life.

unterhausen

apparently you need a tap handle with more clearance.

Andrew R Stewart 

IT's been a long time since I broke a tap in a frame, other projects more recently. Tap removals have been about 50% successful... I have been less acceptant of using older taps as I have aged. Inpatients vs experience can be a fine line sometimes. Glad this worked out and that you can repay your neighbor equally well in the future. Andy

duanedr 

It's a little Starrett that's about 3" long. I forget the model number. It is dedicated to these because it fits pretty well into tight spaces. I just tried to get one too many turns out of it!

I just gained some experience that will hopefully help with my impatience!! Ha! This one has been in the stand too long, it was time to walk the dogs, and too many other things on my mind. Live and learn. I just ordered a few more taps from McMaster.

Andrew R Stewart 

For taps I pretty much only get TiN coated gun types. These push the chips ahead of the tap, making for less jamming up of the chips between the tap's flutes and the hole sides. TiN coated to last longer. If a two fluted tap is available I would choose that as the tap's body will be stronger. Andy (who has a wide selection of tap handles including extensions and a ratcheting handle)

unterhausen

Irwin sells tap adapters for socket wrenches. I have a set, haven't had the opportunity to use them. I bought them to add an encoder to my lathe, but it turned out my tap handle just cleared. They might be useful when I have to do something like tap a water bottle boss.

But on this I'm not sure why you couldn't just get a longer tap handle to clear the seat stay.

dsaul

One of the reasons all of my frames have removable seat post clamps. If you damage a removeable clamp, you throw it away and get a new one. No repair and repainting of the frame involved. Drew at Engin cycles makes and sells two bolt dropper post seatpost clamps. https://engincycles.com/all-products/engin-seat-collar

TiHabanero

Duane, is there a reason you did not start the tap from the non-drive side? This is the approach I took many years ago to put an oversized bolt in the ears after the owner striped the threads out of the hole.

duanedr 

No reason. I was at the rear and I'm right-handed. In other words, no method to my madness.

duanedr 

No reason. I was at the rear and I'm right-handed. In other words, no method to my madness.

JohnDThompson 

If a tap extractor fails to remove a broken tap, a machine shop could use electric discharge erosion to remove it.

duanedr 

In this case, there was enough sticking out that I was able to grab it with vice grips and turn it so that it progressed through the hole. it was a relatively easy repair that took an extra hour or so to complete due to my friend visiting with a flask of bourbon 'to help'. I've seen instances where folks have TIG'd an extension to the tap as well. I don't have TIG. Worst case, I would have un-silvered the binder and replaced with a new one. In some instances, a visit to a machine shop might be required.

Macguyver909

For what it's worth, they also make "pulley taps" which are made for tapping the hub on a pulley, and are extra long. These would definitively fix the tap handle problem but also introduce a straightness problem. (it's hard to get them started straight with so much hangin out). Starting these from the clearanced side should work pretty well to hold them straight though.

unterhausen

I think I'd rather have a 12" long tap handle than one of those long taps. It's a bit weird there don't seem to be medium length tap handles. McMaster has an 8" long one.