Page 1 of 2 1 2 LastLast
Results 1 to 25 of 32
  1. #1
    mtbr member
    Reputation: fernandoj's Avatar
    Join Date
    Mar 2008
    Posts
    90

    A small contribution about frame jigs

    There are a handful of approaches to design a bicycle frame fixture. Taking advantage of Henry James knowledge from his website and my own researches I have ended up with this article about the existing possibilities. A lot of information spread all over the bike forums that somehow I wanted to gather and analyze.


    Holland custom frame in an Anvil fixture

    Jigs can be classified according to different criterias: professional solutions vs. hobbyists fixtures, horizontal configurations vs. vertical mountings, tack-only vs. fully weld frame jigs, mass-oriented production jigs vs. custom frame geometry units, beam inspired types vs. beamless jig designs, multipurpose and extensible jigs vs. simplified versions, the place where you start to assemble the tubes on the jig and so on.

    Professional fixtures will provide full access to each joint for TIG welded and fillet brazed construction without the hassle of tacking and removing the frame in order to fully weld it apart. At the same time is easy to remove and replace the frame during the assembly process, especially important when using lugged construction or when we want the gravity to assist the welds, which is a good thing.

    Jigs having vertical structural plates and/or members are superior to horizontal or backbone based models. Their individual clamping components are shorter, located closer to the joints and connections, hence stiffer than the same type of fixture that has to extend all the up from the base plate.

    Homemade tack-only jigs are affordable if you are planning to build just lugged bicycle frames. Roomier units that provide enough clearance to fully weld the frame vertically on the jig can be achieved with DIY beam designs at the expense of more complexity when determining, for example, the BB drop as it will be “floating out in space”.

    Pure beam style jigs for mass production (the ones used in BMX companies for example) have limited range of adjustment but work well and offer a lot of access for peanuts. On the other hand, jigs that combine compact plates and adjustable arms via extensions that hold the “bearing areas” (BB, HT and rear axle) generate almost endless geometry combinations with good clearance.

    Fixtures made of beams are very rigid and provide great accuracy if we go for extruded aluminium profiles and machined parts. On the downside, aluminium can be considered a bit expensive compared to wood or traditional metallic square profiles.

    A multipurpose jig will meet more framebuilders needs, for example integrating a fork building feature in the rear axle frame fixture, or offering motorcycle jig capabilities.

    Finally choose the jig that makes the tubing logic assembly fancier for you. Building from the BB up is a better alternative in my opinion.

    Here is a brief summary of the frame jig types according to their design:

    No jig. This goes back a hundred years. Accuracy depends on craftsmanship, not tooling. Because no fixture is used, lugged joints often are pinned together by driving nails tightly into drilled holes in every joint. This holds the frame together, and hopefully keeps it in place during brazing.


    Welding bicycle frames in an American factory (not named). Wood engraving Leipzig 1900.

    Flat surface.
    The frame is assembled on a flat plate which is larger than the frame, and made of granite, cast iron (steel) or aluminum, or for beginners, particle board or plywood. Fixtures consists on shims, vee blocks, or other holders that locate the tubes on the center line of the frame. Setup takes forever, and access is limited. Used for tacking only. A good choice for building your first frame considering a flat surface is also needed to check the alignment.

    A small contribution about frame jigs-3-flat-surface.jpg
    A flat surface, machined fixtures and a full size drawing is enough for precise framebuilding

    Modified flat plate or vertical plate jig. Still intended only for tacking, The plate is shaped specifically for a range of common frame configurations in an attempt to provide better access. It has specially designed holders for head tube, rear axle, etc. but still with limited capabilities. Because intersecting tubes (HT and BB) and rear axle are clamped it can be mounted vertically.


    A massive flat plate design that has been tailored to extreme dimensions

    Parallel beams jig. Here the plate is replaced with beams that are parallel to the head tube and seat tube. These beams rest on one or two cross beams that are intended to keep the structure flat. This style of jig is very sensitive to warping of the beams. Most beam materials are not inherently dimensionally stable, so internal stresses and external stresses from torch heat, etc., can lead to a loss of accuracy.

    To use this style of jig you move and rotate the beams to set the jig up. The problem is that the beams are parallel to the tubes, limiting access just like the plate jigs. The net result is still a tacking jig without the simplicity of the plate jigs, or the access of the compact plate jigs.


    The resulting jig is lighter and more portable than any flat plate design

    Compact plate jig. On a compact plate jig, the plate is much smaller than the main triangle. Adjustable arms extend out to support the head tube, BB shell, and rear axle. Carefully designed, offers the best combination of clearance, rigidity, fast accurate set-up and versatility.

    Because of the compact design, these jigs can be much lighter than other jigs, making it much easier to rotate the jig as you weld, and the jig takes up much less space in the shop.

    Sputnik and Henry James proffesional frame fixture are ample proof of this design.

    A rare variation of this style uses no plate at all, just a bunch of arms that support critical parts of the frame. Both Anvil and Bringheli jigs implement this design.


    Sputnik stands out as one of the best choices

    Bottom up or backbone jig. A narrow (4″-6″ wide) four foot long bar or beam is the base of this style of jig. The frame sits upright on this base. Along the base are supports for the BB shell, rear axle, and head tube. Additional supports may be added to hold the seat, top and down tubes.

    Only the axle and BB shell which are close to the base are accurately held. All the other supports extend a relatively long distance from a very narrow base, so errors and tolerances are magnified. Set up is usually slow.

    An almost jigless version of a frame fixture can be achieved thru this design. The method is proposed here following famous Paterek instructions.


    The main disadvantage on this is that you never see the complete picture of the frame until you tack in the last tube. You can’t set it up and then have a sanity check where you can see if it all makes sense

    External jig or motorcycle jigs. A rectangular framework structure is sized so that the bike frame fits completely inside the structure. For this reason, these are sometimes referred to as “picture frame” jigs.

    A foundation of a wide rail, multiple rails or table are built upwards with the jig fixtures supported from below. Arms extend inwards to support the head tube, BB shell, axle, and seat tube. Because the framework must be the largest of any style of jig, and because the framework members must be heavier to provide the stiffness this large size structure requires, these jigs are heavy and expensive. The inherent problem with this style is that the largest frame you can build is limited by the size of the framework. And, if you make the framework really large, the extensions that hold the bike frames must reach in much farther to build very small frames.

    It is stable by itself without the need of mounting platforms.

    A variation is a hybrid jig with a smaller framework offset to the rear with extension arms for the axle and/or head tube.


    Supacustom bicycle and motorcycle frame jig

  2. #2
    mtbr member
    Reputation: Eric Malcolm's Avatar
    Join Date
    Dec 2011
    Posts
    472
    Hey, great over-view.

    I made my first frames (lugged) by the freehand method. Oddly, I still prefer to do it that way. Mine always came out straight. Butt welded, I have used variations of plate and presently am using a form of bottom-up beam and motorcycle jig. They all work well as it is likely each jig becomes personal and you adjust to each types little quirks.

    Nothing, however beats acurate mitres, prior to welding. The jig can never compensate for poor mitering.

    Thanks for your great article.

    Eric
    If I don't make an attempt, how will I know if it will work?

  3. #3
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    2,013
    I use two jig types. A flat plate style using Alex Meade blocks and a beam style (made by me). The flat plate style is fantastic for front triangles.

  4. #4
    mtbr member
    Reputation: fernandoj's Avatar
    Join Date
    Mar 2008
    Posts
    90
    I'm about to finish

    Bicycle frame jigs (2/3) | Llave inglesa - by fernandoj

    Tomorrow I'll post a quick review of some pro jigs and handmade ones. Happy New Year.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Feb 2013
    Posts
    40
    Interesting - that chainset clearance device is clever...

  6. #6
    mtbr member
    Reputation:
    Join Date
    Aug 2009
    Posts
    31

    Re: A small contribution about frame jigs

    You do realize that cast iron and steel are two different metals with very different properties?

    I would argue that many if not most "professional jigs" are tack only seeing as few professionals weld the full bike in a jig.

    Sent from my XT907 using Tapatalk 2

  7. #7
    mtbr member
    Reputation:
    Join Date
    Feb 2013
    Posts
    40
    I don't know about that - just watched a show in the UK featuring Rourke Cycles, and they have a neat flip-over jig. I also have several jigs that are built to braze the whole frame in, for recumbent frames and Brompton rear triangles.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Aug 2009
    Posts
    31

    Re: A small contribution about frame jigs

    Quote Originally Posted by BenCooper View Post
    I don't know about that...... I also have several jigs that are built to braze the whole frame in, for recumbent frames and Brompton rear triangles.
    Not sure how a rear frame jig for a folding bike or one example of a framebuilder with a shop built rotisserie jig proves much. I'll stand by my statement that most framebuilders, professional or otherwise, tack in the jig before welding the frame outside of it.

    The attempt to categorize jigs as "professional" or not based on whether the entire frame can be welded in the jig is nonsense.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Nov 2007
    Posts
    106
    Welding vs tacking in jig is more related to TIG vs braze joints-
    Correct TIG welding needs to be done bathed in argon/no oxygen. So they often use a jig plumbed to fill the tubes w/argon. O/A welding is generally not completed in a jig because it takes too much heat to overcome the HT & BB cones and that warps tubes.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Feb 2013
    Posts
    40
    The attempt to categorize jigs as "professional" or not based on whether the entire frame can be welded in the jig is nonsense
    I'd agree with that. Production frames are probably more likely to be completed in the jig, especially TIG welded frames (the vast majority) because the jig can be plumbed in for argon.

  11. #11
    mtbr member
    Reputation: adarn's Avatar
    Join Date
    Aug 2009
    Posts
    289
    yeah, the "professional" vs "handmade" vs "hobbyist" distinction is a pretty major misinterpretation here. The number of professionals making quality frames using fixtures of their own creation, or even none at all, far outnumbers the quantity of hobbyists making super janky frames on their commercially available jigs.

  12. #12
    mtbr member
    Reputation: chernichovsky's Avatar
    Join Date
    Mar 2011
    Posts
    119

    Laser cut Jig

    Here is mine:

    my philosophy is making a jig that can be "twisted" on the plane level - the base surface
    into place - straight.
    Takes tandems as well :-)A small contribution about frame jigs-img_9569.jpgA small contribution about frame jigs-img_9534.jpgA small contribution about frame jigs-chernibikes.jpgA small contribution about frame jigs-993671_560344590691620_47898335_n-chernibikes-jig.jpg
    www,chernibikes.com

    HAND CRAFTED RIDING MACHINES @ Face Book
    Chernichovsky Bicycle Labs

  13. #13
    mtbr member
    Reputation: alshead's Avatar
    Join Date
    Oct 2007
    Posts
    1,286
    I know there are a ton of threads and the instructables link and all of that, but why doesn't someone make a 8020 style jig and sell it? Seems parts and machining are $500 or less. You could sell it for $1000, and it seems like it would be superior to a Bringhelli or the like. I used a Bringhelli on my first frame and it was a PITA to set up.
    "There are two kinds of mountain bikers in the world: those who are faster than me, and me."

  14. #14
    mtbr member
    Reputation:
    Join Date
    Dec 2012
    Posts
    35
    I think you'd have a hard time making any money at $1000 if you consider the time it would take to machine the parts. You'd have to machine them yourself to get anywhere near $500 in cost. I know from experience that the stock 8020 joining plates/angle brackets are useless for a frame jig if you want accuracy. They are too flexible and have too much slop in them to allow you to retain any sort of accuracy after making an adjustment. The angle plates won't hold anything square unless you have a plate on each side and clamp it together before tightening. I have replaced nearly every joining plate on my jig with 3/4" aluminum bar stock to allow me to quickly make adjustments without checking my alignment every time.

    Name:  12597705325_6e92d6f76e.jpg
Views: 709
Size:  76.8 KB

  15. #15
    mtbr member
    Reputation: adarn's Avatar
    Join Date
    Aug 2009
    Posts
    289
    Quote Originally Posted by alshead View Post
    I know there are a ton of threads and the instructables link and all of that, but why doesn't someone make a 8020 style jig and sell it? Seems parts and machining are $500 or less. You could sell it for $1000, and it seems like it would be superior to a Bringhelli or the like. I used a Bringhelli on my first frame and it was a PITA to set up.
    Not even close. I spent over $800 in materials on my 8020 jig, and after all of the time and thought that I put into it, I can't believe that anvil and others get away with selling their fixtures for so cheap. The prices of "Professional" framebuilding tools are crazy reasonable.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jun 2007
    Posts
    157
    Quote Originally Posted by adarn View Post
    Not even close. I spent over $800 in materials on my 8020 jig, and after all of the time and thought that I put into it, I can't believe that anvil and others get away with selling their fixtures for so cheap. The prices of "Professional" framebuilding tools are crazy reasonable.
    https://www.flickr.com/photos/compos...7636556580924/



    This was our proto jig we had way more than a couple of k machining but material is way less cost wise than 8020 type jigs

    We will be offering a much cheaper machined jig after the bespoke uk show it should be around the 1k mark. In Europe only

  17. #17
    mtbr member
    Reputation: alshead's Avatar
    Join Date
    Oct 2007
    Posts
    1,286
    DSaul- how much do you think you have into your jig?

    Adarn- There is a price break somewhere when having things produced en masse (machining, etc)- sure, making ONE jig is going to cost any one individual lots more money and time. Your jig is super cool and the work that went into it looks fun, frustrating, time consuming, and very educational. But what if you made another one? Materials might even cost the same, but wouldn't your time be cut in half (or more)? And if you were producing 10 at the same time, certainly your materials costs would go down.

    Compositepro- why only UK? Could you potentially find a US distributor?

    Trust me, I think that the Anvil is worth every penny- it's beautiful, well honed over the years, Don is the man, and any of you doing this professionally know about insurance and overhead and R&D, etc, etc, but the Bringheli and some of the other "cheaper" options certainly don't have a lot of R&D and they don't seem to be making many improvements from any year (or decade) to the next (unlike Anvil)- it just seems like there should be something more like DSaul's or CompositePro's that could be a pretty nice jig, still basic, but solid for the $1000-1500 mark.

    Disclaimer: I am a total newb, have no machining experience and have never built my own jig. Thanks for entertaining me. Sorry for derailing the thread at all- the OP did an awesome job with this one and I vote it should be stickied. Stickidized. Stuck.
    "There are two kinds of mountain bikers in the world: those who are faster than me, and me."

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jun 2007
    Posts
    157
    Quote Originally Posted by alshead View Post
    DSaul- how much do you think you have into your jig?

    Adarn- There is a price break somewhere when having things produced en masse (machining, etc)- sure, making ONE jig is going to cost any one individual lots more money and time. Your jig is super cool and the work that went into it looks fun, frustrating, time consuming, and very educational. But what if you made another one? Materials might even cost the same, but wouldn't your time be cut in half (or more)? And if you were producing 10 at the same time, certainly your materials costs would go down.

    Compositepro- why only UK? Could you potentially find a US distributor?

    Trust me, I think that the Anvil is worth every penny- it's beautiful, well honed over the years, Don is the man, and any of you doing this professionally know about insurance and overhead and R&D, etc, etc, but the Bringheli and some of the other "cheaper" options certainly don't have a lot of R&D and they don't seem to be making many improvements from any year (or decade) to the next (unlike Anvil)- it just seems like there should be something more like DSaul's or CompositePro's that could be a pretty nice jig, still basic, but solid for the $1000-1500 mark.

    Disclaimer: I am a total newb, have no machining experience and have never built my own jig. Thanks for entertaining me. Sorry for derailing the thread at all- the OP did an awesome job with this one and I vote it should be stickied. Stickidized. Stuck.
    Europe is where we are based in Europe there is no one doing a good OOB jig, we developed ours and a whole range of other stuff for building production frames, tube blocks heatsinks etc AND MAKE ENOUGH of them to sell them ,so we have been looking at it

    I put some plans out there for free many years ago 2006 iirc and it was a fixture that did both a fork jig and frame jig in one it was aimed at the guy who didnt have a machine shop and even if they had to get parts machined it wasnt earth shattering

    We now have our own production equipment which means we can take that design an put it out there complete, there are several companies working on cheap end jigs for builders in europe and so we think we can do it well

    what we will be making is the version that gets the guy with no machine shop a super jig for the same as they could build one, its the jig before you decide to get by with till you decide its time to buy an anvil, they takes their choice bringhellis etc are old designs that were the only game in town this is changing but people still think its their only choice OOB at the low end

    its not our main buisness but the amount of enquiries ha been quite surprising

  19. #19
    J_K
    J_K is online now
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    124
    Quote Originally Posted by compositepro View Post

    We will be offering a much cheaper machined jig after the bespoke uk show it should be around the 1k mark. In Europe only
    Sounds promising! 1k Pounds or USD or Euros?

  20. #20
    mtbr member
    Reputation:
    Join Date
    Dec 2012
    Posts
    35
    Quote Originally Posted by alshead View Post
    DSaul- how much do you think you have into your jig
    I would estimate that I have about $800 in my jig right now and still need to get some head tube pucks and a cone turned for it. It could have been done for less if I knew what I needed from the start, but the knowledge I've gained from making revisions as I use it has been priceless.

    If you are doing volume, you could probably keep the costs down and sell it at a reasonable price. The best option would probably be to just make the machined parts and sell them as a kit with the end user buying his own extrusions and assembling it.

  21. #21
    Shamisen Appreciator
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,874
    I just want to point out a few things that are probably obvious.

    If you're already at the point where you're getting paid to build bikes, building fixtures could be way more expensive than it appears on the surface. I don't think there's a combination of OTS parts out there that lets you assemble your own without some machine work. So you not only have the cost of all the components of the fixture, you have to machine something or pay someone to machine something. If you're doing it yourself, you're also NOT building something that will bring in a paycheck.

    Building tools is super fun, very educational and no one really knows your process like you do so it's an opportunity to make something that works perfectly for you. People who are in a position to spend the time required to develop their machining abilities without much regard for how much time ($$) they're spending on those projects are well served to do so.

    I love making tools and the longer I do this I have ample opportunity to make stuff that lets me make stuff better or faster with the hope that it'll pay off over the long term. I recently made a fixture that serves double duty as a dual position (dropout and steerer) fork blade mitering fixture and "sweet stay" mitering fixture. Mostly because of my relatively rudimentary equipment (I don't have any type of power saw to chop up plate into workable sizes) it took me 60+ hours to design and build it. That's two frames that I didn't build on top of what I paid my nanny for that time. That quite possibly makes it the most expensive fork blade mitering fixture ever.

    The moral here that making your own tools is great...just don't think it's saving you money. Odds are that it's not.
    Sean Chaney :: Owner/Builder :: Vertigo Cycles LLC
    flickr :: www.vertigocycles.com

  22. #22
    mtbr member
    Reputation: alshead's Avatar
    Join Date
    Oct 2007
    Posts
    1,286
    Quote Originally Posted by DSaul View Post
    I would estimate that I have about $800 in my jig right now and still need to get some head tube pucks and a cone turned for it. It could have been done for less if I knew what I needed from the start, but the knowledge I've gained from making revisions as I use it has been priceless.

    If you are doing volume, you could probably keep the costs down and sell it at a reasonable price. The best option would probably be to just make the machined parts and sell them as a kit with the end user buying his own extrusions and assembling it.
    Yep- I love the idea. Now, just wish someone who had the experience and knows what is needed, etc would do it .
    "There are two kinds of mountain bikers in the world: those who are faster than me, and me."

  23. #23
    mtbr member
    Reputation:
    Join Date
    Jun 2007
    Posts
    157
    Quote Originally Posted by smudge View Post
    I just want to point out a few things that are probably obvious.

    If you're already at the point where you're getting paid to build bikes, building fixtures could be way more expensive than it appears on the surface. I don't think there's a combination of OTS parts out there that lets you assemble your own without some machine work. So you not only have the cost of all the components of the fixture, you have to machine something or pay someone to machine something. If you're doing it yourself, you're also NOT building something that will bring in a paycheck.

    Building tools is super fun, very educational and no one really knows your process like you do so it's an opportunity to make something that works perfectly for you. People who are in a position to spend the time required to develop their machining abilities without much regard for how much time ($$) they're spending on those projects are well served to do so.

    I love making tools and the longer I do this I have ample opportunity to make stuff that lets me make stuff better or faster with the hope that it'll pay off over the long term. I recently made a fixture that serves double duty as a dual position (dropout and steerer) fork blade mitering fixture and "sweet stay" mitering fixture. Mostly because of my relatively rudimentary equipment (I don't have any type of power saw to chop up plate into workable sizes) it took me 60+ hours to design and build it. That's two frames that I didn't build on top of what I paid my nanny for that time. That quite possibly makes it the most expensive fork blade mitering fixture ever.

    The moral here that making your own tools is great...just don't think it's saving you money. Odds are that it's not.

    hits Nail on head

  24. #24
    The cat's name is jake
    Reputation: BungedUP's Avatar
    Join Date
    Aug 2003
    Posts
    227
    Ironically, I have been in the process of making a new frame fixture, in between paying jobs. I'd be happy to make a couple of extra fixture kits (sans extrusion) for 1k a piece. I can provide some photos of the parts when I'm at home.

    email me at peter@whipsmartfab.com if you are interested.

    (corrected after seeing Drew's astute note - Thanks!)

    -Peter

  25. #25
    will rant for food
    Reputation:
    Join Date
    Jan 2010
    Posts
    2,928
    EDIT - now irrelevant
    Latitude: 44.93 N

Page 1 of 2 1 2 LastLast

Similar Threads

  1. your home made jigs
    By adarn in forum Frame Building
    Replies: 117
    Last Post: 12-18-2013, 08:40 AM
  2. My 907 Contribution
    By Radbach in forum Fat Bikes
    Replies: 16
    Last Post: 12-12-2011, 07:28 PM
  3. Off the jigs and slammi'n the trails
    By chernichovsky in forum Frame Building
    Replies: 9
    Last Post: 08-02-2011, 03:34 PM
  4. Doable??? Swaping Components from a Large frame to a Small frame????
    By Yellowr6 in forum Lights DIY - Do It Yourself
    Replies: 2
    Last Post: 04-21-2011, 01:14 PM
  5. My Photo Friday contribution.....
    By brianc in forum Arizona
    Replies: 10
    Last Post: 02-14-2011, 02:17 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •