Please see my thread in classfieds if you are interested in buying my jig
I'm too far into building my own to buy yours, but I'd be very interested to know what you found worked and didn't work on yours. I've got a fair idea about how I want mine to be, but I'm still at the stage where I can make changes based on other people's experience.
There are quite a few things, ill have a think over my dinner and write them down and get back to you in an hour or so.
ok, so i had a think
Things i dont like about my jig were,
Ht/st angle were measured by digital angle gauge, this was not very nice, slow and not very accurate as it relies on the jig being stable. Some kind of graduated scale is 100x better and certainly worth the effort
If your using tslot extrusion make sure you get basic nuts/bolts that are fixed rotation. Some allow the nut/bolt to rotate counterclockwise inside the t slot. This allows the nut to be removed without sliding it out the end. however it also means that the nut rotates and removed itself if you ever undo it. this was a massive pain
I assumed that some parts would limit their own movement more than they did. Try to define every parts movement in every axis. don't rely on bolts in tslot or that kind of thing to hold a part in the same place every time
Rigidity is more important than i realised. when i built my jig i thought that its wasnt critical, however i soon realised it is very important, try to build rigidity into every part as much as possible.
As previously stated, try to build in graduated scales for everything, i was planning on using rulers and measuring, this is a pain in the butt, totally not worth the time saved in making the jig.
Many designs of jig have long support arms to hold the seattube in place, make sure the fixing method for securing the rotation of the arm is solid af. The arm is heavy and long, a small knock at the end of the arm results in a great force exacted on the pivot, meaning its easy to knock the arm and affect the st angle accidentally. This fucked me up on my first frame as i didn't realise and ended up with crazy geo. Make sure the method of fixing the long support arms is effective to prevent them from moving without you noticing.
the ability to rotate the jig in a few different axis is nice, Depending on the fab method (tig/braze/lug) access to different parts is very useful. I have found with tig, that tacking can be a right pain, because some joints have challenging access. Being able to spin the jig upside down would help enormously.
consider how the frame will be removed from the jig and also replaced. Mid build obviously you might find yourself wanting to put the frame in and out of the jig. its nice if it doesn't take 10 minutes every time.
Cobra frames has a good video on his very nice jig which he built, 1000x nice than mine haha
hope this helps
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