started sharpening the points of the lugs (thanks dave bohm) and drilling holes for pins tonight. learned a couple lessons.
• here's background on pinning by Fred Parr. i ordered one of his pinning kits: a bag of nails and two of each drill bit needed.
• tonight i was drilling the pilot holes in a few real and practice lugs. the procedure is prick punch, then center punch, then drill with lots of oil. got the punches at Home Depot; the oil is just 3-in-1 oil. learned about punches from Paterek. they didn't make as big an indentation as i expected.
• i discovered stamped lugs are pretty fragile when i tried to prick punch one rather hard. the opening deformed a little...hopefully i'll be able to re-form it so a practice tube will fit. i bought three stamped lugs from Tom Palermo the other day--really lovely to begin with, great shorelines and windows. i've been practicing lug cutting and now drilling on them.
• i'm using tapered wooden dowels to hold the lugs for filing, so i used to dowel to hold the lug, clamped the dowel horizontally with the right spot facing up, and drilled down through the lug into the dowel. the 8" half round was perfect for cleaning up the holes.
• before calling it a night, i tested out the whole pinning setup. i used a short section i had trimmed from the end of the down tube to get it roughly the right length before mitering. drilled the pilot hole in the lug, drilled through that hole into the tube, deburred both holes, and tapped a pin in. the assembly felt really very strong, although looking back at it i realize the lug hadn't yet been properly reamed out for a good clearance with the tube. 'sposed to be at least a slip fit, but it was still kinda tough to slip that tube in there.
• i recall Fred mentioning something about pinning each tube in at least three places to keep it secure in three dimensions. this may be kinda tricky with the type of jig i'm using, which obviously doesn't allow access to all of the frame at once. i'm working on this one.
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4 comments:
Speaking of pinning, be very careful about where you place them along the lug. Not for any structural reason, but because I just came in from filing down a dt/bb pin that was a real beeatch to get at! It was easy to drill and pin together, but it's a different matter when you're cleaning up and all the tubes are in place. Good luck.
-Chauncey Matthews
thanks so much, Chauncey. exactly the kind of comment i love to see here. a couple questions foryou if you tune back in:
• what are you using to cut the pins off? i plan to use a dremel with a 420 abrasive disc. i think i recall Fred Parr mentioning using them.
• i don't recall seeing you on the framebuilders list; what's your background? how'd you get into building? how'd you find out about this? email me at elabowitz@fast50.net if you don't wanna make it public.
"what are you using to cut the pins off?"
ethan.
hacksaw them off.
file them flush!
Ethan,
I'll bare myself in public, no problem! ;) I think I saw the same thing about cutting the pins- I usually break off the nails by hand on my way into the house to get hot water to soak the just-brazed joint. Then I use a dremel to trim the nubs down. You can get pretty close with the dremel and finish quickly with a file or emery. Unless you're like me and you place the pin in a place that is now blocked by a chainstay!
I use 4d finish nails and a #51 bit (ala Sachs) for my pinning.
How I got into building: I badly wanted a real fixed gear frame after a years of riding old road conversions and I realized that the frame I wanted would have to be custom. Then I saw a post on MTBR.com from a guy that had finished his first frame, he mentioned Suzy Jackson, I found the list and frameforum, read all the archives (found mention of your blog there)- fast forward a year and a month and here I am with the first frame getting painted and facing the headtube on #2 tonight to get it ready to send to powdercoat. So you and I aren't very far apart in this process. Actually, you're doing far more lug prep work and detailed planning than I did, so you're ahead of me there. Shoot me an email if you want to talk about anything in more detail- you probably still have my address, I emailed you before about making the bending mandrel.
So, when are you gonna put some fire to steel and cause some serious damage?
-Chauncey
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