# My Homemade Frame Jig Plans



## retspih (Mar 1, 2012)

CAD'ed this up over the last few days, getting really excited about building my own frames. Haven't machined it yet and probably won't for a couple months, but wanted to share my plans with everyone.

Much inspiration goes to (of course) Anvil. Also, halfway through designing it, I found this awesome homemade jig that was pretty much exactly the same route I was taking: Miranda and Dave - Photo Experiments :: Frame Jig

































the springs are to keep the sliding arm square with the main fixture


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## LONDON-GUY (Oct 3, 2011)

Looks interesting but the best jig in the world will not stop movement in the 2 parts being welded due to to affects of the heat. The art of frame building is tracking it once you have it all finished welded. But good luck with this project.


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## kbiker3111 (Nov 7, 2006)

That is an assembly that screams for 80/20 parts.


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## retspih (Mar 1, 2012)

kbiker3111 said:


> That is an assembly that screams for 80/20 parts.


I think I might be able to actually do it cheaper than with 80/20 bc I have access to a bridgeport and lathe. plus it might be fun to machine myself


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## kbiker3111 (Nov 7, 2006)

retspih said:


> I think I might be able to actually do it cheaper than with 80/20 bc I have access to a bridgeport and lathe. plus it might be fun to machine myself


Depends what your time is worth, but do what you enjoy.


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## retspih (Mar 1, 2012)

kbiker3111 said:


> Depends what your time is worth, but do what you enjoy.


haha full time student...I work in my engineering school's machine shop. When no one's in and needs help, we can work on our own projects.


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## pigpen (Sep 28, 2005)

Looks nice. Mountain bike review has a frame building forum. Have found others also. Have always wanted to get into frame building. Good luck.


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## looigi (Nov 24, 2010)

It looks pretty stout as is but consider adding webs to make the plates into T's, or better yet, channels. T would help stiffen against bending. Channel would additionally help stiffen against twisting.


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## tlg (May 11, 2011)

Just a few comments. It looks inherently heavy yet flexy. As mentioned, 80/20 would be perfect for making it lighter yet stiffer. But I like your thinking of wanting to make it from scratch. Having access to a bridgeport and lathe would make it a fun project. Perhaps you could combine 80/20 with some custom machining?

Also, the red lever clamps look too small to provide a tight connection. Perhaps they're just stock components you inserted into your assembly. But make sure you have some good strong clamps. If you're not doing production frame building, you could just go with bolted connections. Cheaper and easier to get tight.

I wouldn't rely on the springs to keep the sliding arm square with the main fixture. You're going to have about a 30" moment arm. It won't take much to compress them.


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## retspih (Mar 1, 2012)

tlg said:


> Just a few comments. It looks inherently heavy yet flexy. As mentioned, 80/20 would be perfect for making it lighter yet stiffer. But I like your thinking of wanting to make it from scratch. Having access to a bridgeport and lathe would make it a fun project. Perhaps you could combine 80/20 with some custom machining?
> 
> Also, the red lever clamps look too small to provide a tight connection. Perhaps they're just stock components you inserted into your assembly. But make sure you have some good strong clamps. If you're not doing production frame building, you could just go with bolted connections. Cheaper and easier to get tight.
> 
> I wouldn't rely on the springs to keep the sliding arm square with the main fixture. You're going to have about a 30" moment arm. It won't take much to compress them.


Yeah maybe I should consider doing 80/20 for parts of it. like just the main part and the two arms.

clamps are just from mcmaster carr. was planning on getting something more heavy duty, were kinda just place holders for the assembly.

the springs at the around .25 inch deflection I have in my assembly had a load of about 60 lbs/each which I figured might be enough to keep it square? Maybe i'm wrong


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## tlg (May 11, 2011)

retspih said:


> the springs at the around .25 inch deflection I have in my assembly had a load of about 60 lbs/each which I figured might be enough to keep it square? Maybe i'm wrong


With the frame in the vertical position, depending on where the pivot point is, only one spring may be doing the work. But even if both are, with a 30" moment arm, only 4lb would be required to generate 120lbs at the springs. The weight of the arm itself would probably do that. 
I think you'd need a spring force of a few hundred pounds to keep it square and not flex. Which would then make it really hard to slide. Not to mention, spring steel sliding on aluminum is going to gall. 
Suggestion: A nylon pad with some fine pitch screws you could use to adjust the pad snug yet still allow it to slide. And of course... 80/20 has some nice linerar slides with nylon pads.

BTW... what modeler are you using? I'd love to take a look at the model if you don't mind sharing.


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## retspih (Mar 1, 2012)

tlg said:


> With the frame in the vertical position, depending on where the pivot point is, only one spring may be doing the work. But even if both are, with a 30" moment arm, only 4lb would be required to generate 120lbs at the springs. The weight of the arm itself would probably do that.
> I think you'd need a spring force of a few hundred pounds to keep it square and not flex. Which would then make it really hard to slide. Not to mention, spring steel sliding on aluminum is going to gall.
> Suggestion: A nylon pad with some fine pitch screws you could use to adjust the pad snug yet still allow it to slide. And of course... 80/20 has some nice linerar slides with nylon pads.
> 
> BTW... what modeler are you using? I'd love to take a look at the model if you don't mind sharing.


Good suggestion. To be honest, I was totally intimidated by 80/20's catalog I decided to skip the headache and design myself. I guess it's worth a look...oh well. i had some fun practicing my modeling skills.

I used Solidworks, can send you the files if you want. PM me with your email.


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## tlg (May 11, 2011)

retspih said:


> Good suggestion. To be honest, I was totally intimidated by 80/20's catalog I decided to skip the headache and design myself. I guess it's worth a look...oh well. i had some fun practicing my modeling skills.


 I agree, their catalog has become overwealming. I remember when they were just starting out and only offered a few items. 
On another note, 80/20 stuff can get pretty pricey. One of their selling points is labor savings, which is irrelevant to you. So it might wind up costing you a bit more.


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## tomk96 (Sep 24, 2007)

very cool


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## UrbanPrimitive (Jun 14, 2009)

Cool looking stuff. I assume that in addition to Anvil you've looked at Sputnik, Henry James, and Bringheli. The arguments about flexibility in the jig don't really apply for building. The jig won't make a straight frame, no matter how stiff it is. The torch is what matters. Besides, if you're doing anything beyond tacking in the jig you have bigger problems.

If it hasn't crossed your radar yet, check out The Framebuilders Collective and Velocipedesalon. Also be sure to check out the Paterek Manual if you haven't already.

Remember to come back here with pics, or it didn't happen. Have fun.


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