For UK buyers, the Mac Industries tables look like really good value. Not a recommendation (yet) but 6mm steel should be pretty solid (not sure if it’s ‘alignment’ solid) and the 1200x800mm table should be large enough to accommodate a reasonably long and/or tall frame.
Here’s my Skynet on the temporary back board (1050x610mm). The frame has reach 505mm, stack 610mm, chainstays 415mm.
I think somebody said it well, that the different ideas can enable a person to meet their goals within their budget. Here is what I did in 2022 for less than $800. Plans on the net in an instructable. PMW parts not totaled in the final talley. Some mods, some threaded rod and other bits may not be in the budget pic. Is it pro? No. Does it work and align? Yes.
Here are a couple of quick renders of what I was thinking with the XY-style table-based jig.
PVD-style axle tower and BB tower (with the larger diameter from Samantha), laser-cut 10mm plates for the table-interfacing parts, 6mm laser-cut for the uprights and off-the-shelf 8020-compatible angle brackets. 200mm centreline as with Samantha. The cones would be same as Samantha too, so fitted and aligned with 16mm shoulder bolts. It’s mocked up here with the dimensions of the frame in my other post. A lot of the parts would be easily transferable to a beam-style jig and the seat-tube beam could be removed from the BB post and used freestyle if more flexibility was wanted.
I looked at your instructable many times before I did my jig. At least I think it was yours… back in 2016/17
No, not my instructable, just the one I followed. Obviously many paths to get where you need to. Works fine for what I’ve done so far.
This looks really good. What’s the minimum size table that could be used for doing just front triangles?
Depends on the frame dimensions, obvs. My frame used for illustration has a 505mm reach and 66° head angle so would require a horizontal head tube position of 700mm (actually 700.2mm but I think we can safely ignore the .2mm). The head tube beam as designed is intended to stick out beyond the edge of the back plate by up to 50mm so a plate with 650mm minimum horizontal fixture distance would suffice in this case.
Here’s a mockup of a table JIG, based on “standardized” parts lasercut avec machined.
You can use them to build frame, forks, strange frames too.
https://www.romainthouin.com/project.php?projectID=sccTable
Each part moves only of 50mm, cause the rest of the movement can be done by moving it in the JIG.
I machined few of them and use it for notching tubes (you can swap the cones with bearing and arbor as a tube notcher), and you can swap the “axle holder” with a simple V block.
I recently added to the system a tube bender, with 3D printed rollers
And now I as any of us here need to upgrade to a real welding table, in order to increase accuracy.
Not sure if anyone here follows July Bicycles, but they’ve been posting some nice renderings of their bikes and jigs lately that may have some nice insights for this open source project. They have some things specific to their process (also super interesting) but a lot of similarities to some of the ideas in here.
I like the general design concept of this jig; but how do you have any assurance of accuracy? Even if the beam is ground flat/square, how are the brackets and attachments accurate?
You either have the fabicator do their own calibrationa nd sign off on it or you do that yourself when you get the jig into your workshop.
2 builders in my home town use chopsource jigs so i assume it’s “good enough” at least. I have no personal experience with it
Check out
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https://www.instagram.com/p/Cx6fpLAv1dR/?igsh=eTA4cHJ0MnU4aWNy
With the “Chop source” jig there is no adjustment that I can see, it will depend on the straightness of the beams and let me tell you, they are not straight and they move over time.
That said, it’s a common problem with the beam designs, especially if they use a steel beam like CS or Bicycle Academy.
For example the BA fram jig (that I use) can be adjusted in all dimensions and they give you a laser level and instructions on how to adjust it and you should do it before setting a new frame up - it’s a clever design, I believe it can be made even better with some improvements - but that comes at a higher price tag.
No idea how the chop source jig does it if it does it at all BUT, with a laser level and some ingenuity you may be able to set it up “straight enough” for the purpose of the hobbyist builder
Thanks for the replies. If the jigs are cheap enough, I guess it’s worth the builder’s time to adjust their accuracy for each new frame setup with a laser level. That said, I read years ago about a beam-type jig that had the beam “Blanchard ground”. Presumably, the vertical arms were also accurate/square, or the builder would still be chasing inaccuracies.
yes, there are beams that comes with a certain degree of straightness, those are usually alu extruded beams, each manufacturer has its own charts and accuracy levels and those match their prices.
One could get the “chop source” jig alongside with their rotisserie stand (very smart design there) and upgrade the beams to be extruded alu and get a higher degree of accuracy.
Same can be said for the Bicycle Academy jig
If I was to design a cheap-cheap-cheap jig right now, I would go with @nickhiti1 design and I would make it even cheaper by only allowing front triangle or rear triangle setup at a time.
Shorter extrusions, less flex, lower cost.
The simplicity of this jig/fixture kinda blew my mind. Thoughts?
https://www.instagram.com/p/C0LtOrVsGTG/?utm_source=ig_web_button_share_sheet&igsh=MzRlODBiNWFlZA==
Also this guy seems to be doing neat things with 3D printing @Daniel_Y !
-Jim G
He is doing neat things with 3D printing. Saw his first one at bespoked Dresden last year—impressive!
Basically, it contains just the HT assembly and the ST assembly mounts. All the remaining stuff - incl. specific angle joints and external brackets from minitec - has to be sourced locally. (This is easy if you are in the US / Europe, but a bit difficult, if you are outside.)
The ideas2cycle design works with the HT clamped at 90°, BB at a fixed point and a bit of trigonometry to calculate CS position. I got this kit a few days ago, but am changing the jig design around a bit. (I am a visual person and need to see the bicycle with a BB drop, slanting tubes and all.) Attaching my work-in-progress jig here… As I said before, it is different from the ideas2cycle design.
