Flat pack MDF frame jig

A1CKot · #1 02-23-2012, 10:00 PM

I know a lot of people want to build frames but this seems too easy. A frame jig made from MDF with a tube set for $499.

The-Jiggernaut

I just don't know about this one...

Doug Fattic · #2 02-23-2012, 11:06 PM

I've been amazed to see this new fixture pop up everywhere on bicycle forums. Whatever the deficiencies in its design, their presentation has been a widespread success. The $299 price for the fixture itself seems very reasonable. Except it isn't something I would want to use or encourage my framebuilding class students to get. It is clever but doesn't appear to be designed by an experienced framebuilder. I can think of lots of changes I would want to make on it.

cat6 · #3 02-23-2012, 11:43 PM

Looks cool, and for $499 seems more than reasonable for an avg joe to give it a go w/the complete kit.

ultraman6970 · #4 02-24-2012, 12:12 AM

My only problem is that is made of wood. No matter how dry it is at some point it will start warping. I can't even imagine to braze in that thing.

Don't take me wrong the idea is super fantastic. It was time for somebody to came up with something like that tho. The bad thing is that you dont need a jig for brazing but what u really need is a darn table to make the corrections before and after brazing.

charliedid · #5 02-24-2012, 12:23 AM

I think it's sorta disposable...make yer fixie and be done with it.

No harm.

Doug Fattic · #6 02-24-2012, 01:11 AM

What interests me most about this fixture is their marketing strategy. I don't know if the designers/makers are the ones putting out word and then having their buddies follow it up with positive comments or what. Whatever, it seems they have gotten a lot of eyes to see what they've made.

Whether or not this fixture could even work for someone (a much lower standard than working well) would depend on their methods of making a frame. There are a number of methods that can get the job done. My way is to simply spot braze a frame (or parts of a frame) in a fixture and then straighten it out on a flat table and then braze it in free space. If one was actually brazing or welding a joint in this fixture it wouldn't work.

Among the problems I see is that the V blocks appear to for one size of tubing (standard? oversize?), it doesn't have any reference marks so how are its positions accurately set to a specific frame design? The list goes on. I'm assuming most visitors to this subject post aren't wannabe framebuilders on the cheap so I needn't be more specific.

cat6 · #7 02-24-2012, 01:22 AM

I'm not buying one, but if I were curious about building my own frame cheap this seems it would be the way to go. It's a small investment to see if it "sticks" and proceed with more expensive equipment/tools from there.

A1CKot · #8 02-24-2012, 05:51 AM

I've never build a frame but I have read a fair bit and always seem to find my way to the frame builders collective forum and this just seems off. Maybe if it was marketed as a frame jig for bamboo frames and then they sold their own line of standardized tubes and lug and all the other epoxy doodads.

Welding or brazing so close to the MDF??? The brake bridge is included according to the picture no fixture seems to be present to locate it. Do you just guess? Does the BB come pre brazed as in the picture? What about facing, chasing and reaming? Close enough is good enough?

It looks cool as a piece of art but as a working tool not so much.

Doug Fattic · #9 02-24-2012, 08:21 AM

A1Ckot, trust me when I say your list of questions about how to use that fixture would be pages long if you actually bought one. But to answer your specific questions, a brake bridge position would be measured with a metric ruler from a rear axle and held in place by the friction of its miters. The method is file a bit, measure, file a bit measure and repeat on each side until it is the right length and the hole is centered. There are various methods to make sure it isn't crooked. The bb and seat tube are brazed together first and don't need to be in the fixture for that. Chasing, facing and reaming is done afterward except for the faces of the bb shell.

I remember chatting with Ben Serotta at the New York bike show way back in the day when he was just a single man operation like me. He said one of the reasons we like to become framebuilders is because we enjoy designing fixtures. Over the years I've spent hundreds if not thousands of hours thinking out how they should be made � often with other engineers. There is a laser cutting company specializing in stainless steel that makes mine.

I suggest that if you are serious about ever making a frame for yourself that you take a class from either me, UBI or Dave Bohm. At the very least you would end up with a frame built for yourself. I've been teaching these classes ever since 1976 after I got back from apprenticing in England. In fact my reason for going in the first place was so I could get the knowledge to be able to teach Americans so they wouldn't have to trek abroad to figure it out. Organizing and presenting how-to-build frames has been my primary life's work.

charliedid · #10 02-24-2012, 08:22 AM

Quote:

Originally Posted by Doug Fattic

What interests me most about this fixture is their marketing strategy. I don't know if the designers/makers are the ones putting out word and then having their buddies follow it up with positive comments or what. Whatever, it seems they have gotten a lot of eyes to see what they've made.

Whether or not this fixture could even work for someone (a much lower standard than working well) would depend on their methods of making a frame. There are a number of methods that can get the job done. My way is to simply spot braze a frame (or parts of a frame) in a fixture and then straighten it out on a flat table and then braze it in free space. If one was actually brazing or welding a joint in this fixture it wouldn't work.

Among the problems I see is that the V blocks appear to for one size of tubing (standard? oversize?), it doesn't have any reference marks so how are its positions accurately set to a specific frame design? The list goes on. I'm assuming most visitors to this subject post aren't wannabe framebuilders on the cheap so I needn't be more specific.

Well Doug, I am certainly in no position to question you and I am certainly not.

That said, it seems since it is a "Kickstarter Project" they are still looking for funding to even get it off the ground. Maybe you could offer your expertise for a consulting fee or percentage of sales?

WillT. · #11 02-24-2012, 10:59 AM

Wouldn't this thing be some sort of fire hazard? I just can't see wood and a torch getting along with each other very well.

Doug Fattic · #12 02-24-2012, 11:13 AM

Quote:

Originally Posted by WillT.

Wouldn't this thing be some sort of fire hazard? I just can't see wood and a torch getting along with each other very well.

Actually the fact that it is made out of wood (actually MDF) is not a problem because (as I mentioned in pervious posts) the tubes are not brazed in the fixture but only spot brazed together (meaning a small spot of braze about the size of a tack head). I've never timed my self but that probably takes less than 10 seconds. If one was really worried about damage to the fixture, they could use a piece of sheet metal as protection. Actually I'd do that anyway to keep it clean from flux. After being spotted together, it is then aligned on some kind of surface plate (or one can use a straight edge with a ruler if on the cheap) before it is really brazed together somewhere else.

jmoore · #13 02-24-2012, 11:17 AM

Is there really a need for a "frame jig for the masses"?

Doug Fattic · #14 02-24-2012, 04:41 PM

Quote:

Originally Posted by jmoore

Is there really a need for a "frame jig for the masses"?

Whether or not there is a "need" depends on one's build philosophy. There is a need to hold tubes in the right relationship to each other somehow whatever those tools may be called. Anyway there certainly is a market for a modestly priced fixture.