pinning in classic frame building atmo -

[e-RICHIE]

this went live today -

Frame building pinning/tacking

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[vulture]

Really cool, I'm a welder myself but I have total respect. Have you ever experienced hearth brazing? A buddy of mine is a blacksmith and we are going to braze some rivets in on some table leg joints, just for fun. Powder flux and some LF bronze. We will see.

[e-RICHIE]

Have you ever experienced hearth brazing?

in london, all the main tube and fork brazing at the shop was done in the hearth. we used it at the front end at witcomb usa. the ordeal is over-romanticized atmo. the hearth is just a pile of fire bricks that trap heat that comes off a torch and bounces it back at the far side of whatever is leaning up against it. it's not even terribly old tech; it's no tech. and the torches we used ran on town gas and put out flames nearly 20" long. there's would be no reason on earth to continue the process in a studio where oxyacetylene torches, fixtures, silver alloy rod, and 20th century processes are employed.

[suhacycles]

That reminds me, is pinning the seat stays to the lug recommended for side tacked joints? Have you seen that joint pop more often if it isn't pinned?

[bellman]

Really cool, I'm a welder myself but I have total respect. Have you ever experienced hearth brazing? A buddy of mine is a blacksmith and we are going to braze some rivets in on some table leg joints, just for fun. Powder flux and some LF bronze. We will see.

Some where in a pile I have a propane burner made from cast pipe fittings with mig tip for a jet. Works killer. The key was flaring a bit of stainless tube for the tip.

The neighbor and I used it for some things just as richard described- with some fire bricks piled up as needed. if you configured them as a pass-thru it would work perfectly for what you want.

I'm going to try and find the plans for the burner for you so you can make it better and then make me one....

[Doug Fattic]

At Ellis Briggs in England where I learned in 1975, they switched from doing hearth brazing frames to Oxyacetylene while I was there. Or more accurately they stopped doing the main joints with hearth brazing and touching up the shorelines with O/A. Jack Briggs was the master builder but Andrew the new guy (who did most of the work) just didn't see the sense in it any more. He saw no point in heating the joint up twice - the second time with O/A to clean up the shorelines so everything looked good at the end. I got the chance to hearth braze several frames while I was there but I don't remember if I did it on the 1st frame I made for myself. E–B had a really nice fixture based on a 3 by 4 cast iron table. Of course we had to pin and spot the tubes together on it before the frame was hung on a stand with firebricks stacked around the joint as close as possible. The natural gas hose itself was huge (it reminded me of a firehouse) and had a squirrel cage type of fan to add oxygen into the large flame. The loud noise it created added to the drama. No delft hand motions would required, I just aimed it straight at the lug and waited until it got up to temperature. The red zone would go several inches up the tubes. I held the brass rod with holder. You could follow the the shadow of the flow of brass as it moved through the joint. It seemed pretty crude but kind of cool too. Not for a second did I think I would do that when I got back to the states.

This method was a residue from technology of the age of when some of these guys (or their fathers) started. I remember talking to the Quinn brothers in Liverpool and they told me they started building frames in their early teens before WWI! They learned from their dad. Jack started building frames in 1938 with his dad as his teacher. They had a system of knowledge and equipment that worked and there wasn't much incentive to change. The Brits at that time where very tight about sharing knowledge (many told me they only talked to me because I was American) because of all the builders competing for a share of the market so their wasn't a culture to share information that might pressure change.

[vulture]

Some where in a pile I have a propane burner made from cast pipe fittings with mig tip for a jet. Works killer. The key was flaring a bit of stainless tube for the tip.

The neighbor and I used it for some things just as richard described- with some fire bricks piled up as needed. if you configured them as a pass-thru it would work perfectly for what you want.

I'm going to try and find the plans for the burner for you so you can make it better and then make me one....

Oh, I don't need a forge, my buddy is fully operational, Orion Forge HandForged Furniture and Iron WorksI was just thinking of dragging some of my brass into his shop and melting it on some steel. I love getting the stock orange and banging on it with a power hammer. I apreciate the history lesson about the hearth , it looks "romantic" but like I said, I'm a welder, thats how I build bikes, 20th century electricity style. That said it is cool to see the old stuff and cool to hear about people who used it. I respect processes I don't know or use, and I respect those who master those processes.

[e-RICHIE]

That reminds me, is pinning the seat stays to the lug recommended for side tacked joints? Have you seen that joint pop more often if it isn't pinned?

hi suhacycles i missed this one - all my stays are pinned to the lug but it's for location and relocation only so that they are in the right place (based on a earlier process done using my frame fixture). but i never considered the strength of the joint affected by the presence of the pin. i compound miter my stay ends to conform to the lugs, and the filler metal is what's holding it together atmo.

[suhacycles]

hi suhacycles i missed this one - all my stays are pinned to the lug but it's for location and relocation only so that they are in the right place (based on a earlier process done using my frame fixture). but i never considered the strength of the joint affected by the presence of the pin. i compound miter my stay ends to conform to the lugs, and the filler metal is what's holding it together atmo.

Gotcha. I've never done a side tacked attachment before and contemplated either doing it that way or filing a groove into the seat lug. I guess the later is riskier if I screw up... ={

[EricKeller]

you see the occasional seat stay/seat lug failure on inexpensive production frames made when someone was having a bad day. I doubt there have been many failures there on bikes that were made with a reasonable standard of care.

[JuanGrande]

A couple of questions regarding pinning

1) What type of drill bit do folks use? I have been using a number 42 (I forget the term... wire size), but the longer bits tend to break. Is there a short bit, similar to a countersink bit that folks use?

2) When drilling the initial holes, is there a trick to keeping things in alignment until the nails get set?

Just seeing this post has me rethinking how I have done things in the past. Thanks.

[e-RICHIE]

A couple of questions regarding pinning

1) What type of drill bit do folks use? I have been using a number 42 (I forget the term... wire size), but the longer bits tend to break. Is there a short bit, similar to a countersink bit that folks use?

2) When drilling the initial holes, is there a trick to keeping things in alignment until the nails get set?

Just seeing this post has me rethinking how I have done things in the past. Thanks.

it's all pretty simple. i use a #51 bit, an electronic drill, and some finishing nails from the hardware store. the ends of the nails are burnished to a finer point and i drive them through the hole. they are not that tight, and not that lose; they are dowels at the point of assembly and allow me to put the frame parts together after they have been fixtured, checked, and rechecked, but before they are fluxed and brazed atmo. don't over think this.

[Andrew R Stewart]

One trick that I've used to create the pin's holes during tube set up is to predrill the sockets with a slightly smaller bit. Then after assembling the tubes and lugs the holes act as a guide for the final drill bit. That there's a hole already in the socket lessens the effort to complete the hole and lessens the chance of the tube shifting (although with common sense about holding things in place and minor drilling skills this isn't really a problem). Also I wil set the first pin in before going on to drill the second hole. If things don't line up then you have only one hole to plug with filler. Andy.

[JuanGrande]

Thanks... this helps. And yes, I am probably over-thinking things - but I also don't need to re-invent the wheel either. Neither of the classes that I took have even dealt with pinning... just toss in the jig and braze. Since I haven't had a jig, plywood, steel tubes, and pinning have been my method for keeping things in alignment.

Thanks.

JC

[e-RICHIE]

Thanks... this helps. And yes, I am probably over-thinking things - but I also don't need to re-invent the wheel either. Neither of the classes that I took have even dealt with pinning... just toss in the jig and braze. Since I haven't had a jig, plywood, steel tubes, and pinning have been my method for keeping things in alignment.

Thanks.

JC

i don't pin to keep things in alignment atmo; they are surrogates for a fixture but only AFTER the tubes are cut, interference fits are confirmed, the assembly refixtured, the goods are fluxed, and the pins driven in hard. at this point the unit is fully removed from the fixture and brazed free hand so that no clamping devices induce stress or the inclination for tubes to pull out of alignment OR out of frame design. at some point in the middle of the aforementioned sequence, the assembly is checked and rechecked on an alignment table to ensure not only that the frame design is tight and mimics the fixture, but also that said pipes are in alignment before all the heat and the bad, bad human error machine shows up.

[drewgh2o]

1) What type of drill bit do folks use? I have been using a number 42 (I forget the term... wire size), but the longer bits tend to break. Is there a short bit, similar to a countersink bit that folks use?

The short drill bits are called screw machine length and dont' wind up and grab as readily as a jobber. Split-point geometry is nice when running a hand drill even in the small diameters. mscdirect.com is god.

[JuanGrande]

Thanks for the tip on the drill bit.

[JuanGrande]

As always Richard, thanks for the insight. I learn a lot from the advice you give and the pics that you post. Thank you. Now I just need to keep building frames and get a feel for things.

[turpentine]

it's all pretty simple. i use a #51 bit, an electronic drill, and some finishing nails from the hardware store. the ends of the nails are burnished to a finer point and i drive them through the hole. they are not that tight, and not that lose; they are dowels at the point of assembly and allow me to put the frame parts together after they have been fixtured, checked, and rechecked, but before they are fluxed and brazed atmo. don't over think this.

PS cobalt bits.

[e-RICHIE]

PS cobalt bits.

i use some pretty basic HSS bits from MSC. it's an incredibly low tech operation driving a hole through the two parts atmo.