choosing a jig

[Matt92]

Hello everyone,

I'm new to the forum so I'll start by introducing myself.
I'm calling Matt, 47 years old, I have a few years of motocross, BMX, MTB practice.

After having been a bicycle and motorcycle mechanic and a motorcycle custom builder, I now want to devote myself to bicycle frame construction.

For this I am in the process of equipping myself with certain tools, the first on the agenda is the JIG.
I selected 3 models :
- HYDRA from Bike Machinery
- Sputnik Tool
- Cobra frame

The Hydra is really very expensive, the other 2 are more reasonable at the moment.

I wanted to get feedback from users, in order to guide me towards a sustainable choice.

I therefore welcome all of your comments on the 3 types of JIG,

Best Regards
Matt

[j44ke]

Hello everyone,

I'm new to the forum so I'll start by introducing myself.
I'm calling Matt, 47 years old, I have a few years of motocross, BMX, MTB practice.

After having been a bicycle and motorcycle mechanic and a motorcycle custom builder, I now want to devote myself to bicycle frame construction.

For this I am in the process of equipping myself with certain tools, the first on the agenda is the JIG.
I selected 3 models :
- HYDRA from Bike Machinery
- Sputnik Tool
- Cobra frame

The Hydra is really very expensive, the other 2 are more reasonable at the moment.

I wanted to get feedback from users, in order to guide me towards a sustainable choice.

I therefore welcome all of your comments on the 3 types of JIG,

Best Regards
Matt

Hi Matt - and welcome - I've moved this thread into the Framebuilding Forum section for direct access to The Knowledge.

Note that we also have a motorcycle section too.

[VertigoCycles]

Hello everyone,

I'm new to the forum so I'll start by introducing myself.
I'm calling Matt, 47 years old, I have a few years of motocross, BMX, MTB practice.

After having been a bicycle and motorcycle mechanic and a motorcycle custom builder, I now want to devote myself to bicycle frame construction.

For this I am in the process of equipping myself with certain tools, the first on the agenda is the JIG.
I selected 3 models :
- HYDRA from Bike Machinery
- Sputnik Tool
- Cobra frame

The Hydra is really very expensive, the other 2 are more reasonable at the moment.

I wanted to get feedback from users, in order to guide me towards a sustainable choice.

I therefore welcome all of your comments on the 3 types of JIG,

Best Regards
Matt

I've used Arctos (four different ones), Bringheli (also four different ones), Anvil Journeyman and a Sputnik. I owned the Journeyman and currently have the Sputnik (though it is up for sale). Of those four choices, I prefer the Sputnik but it's because it suited the way I build best and is the most rigid of the bunch, it's also the easiest to setup of the four.

One thing to keep in mind is that you're going to have to get to know the "personality" of whatever fixture you choose. I haven't used a fixture yet that's dead straight out of the crate. The Sputnik was the closest, but I still had to shim the back end and pay close attention to how the seat stays were going on. I like Jeff's philosophy which is basically you should be able to setup your fixture, cut tubes to your spec and everything should fit perfectly...you shouldn't have to bump the hard points around to get the miters to fit and you shouldn't have to reference a mitered tube to setup your fixture. I don't know enough about the Cobra tool to offer any comments, but I'll tell you what I like and don't about the Sputnik

Pro's -
being based off a big plate, all the contact points on the front triangle are very rigid and it's setup very accurately.
very fast and easy to setup with an X,Y to the bottom center of the HT and BB ctr as a datum
the puck system on the bottom of the HT is great. No minor fit drifts due to a slight difference in HT I.D.
it's designed so you can tack the full frame and easily remove it from the fixture WITHOUT HAVING TO MOVE ANY GEO ON THE FIXTURE, and it does that very well.
the various tube holders are nice to have. there's a vee block for the TT and a bar that can be used to push the DT into the HT. They hold the tubes in place sufficiently well that you don't have to resort to tape to keep anything from shifting as you rotate the fixture to tack tubes. Especially nice if you've filled the frame with Argon.

Con's -
the axle tower can wrack a bit and you need to learn how to wrack it just right so you can drop your seat stays on and be confident that the back end will be well aligned when you pull it off the fixture. This will be less of a problem with plate dropouts but hooded dropouts create a need for near perfection, especially with modern thru axles
access to the joints isn't great. It's not designed so you can fully weld out the frame in the fixture. For me, a TIG torch with a stubby back cap was a necessity.
it rotates but doesn't tilt. The ability to tilt the fixture while you're tacking is really nice
It's minor, but the ST cone tower could be better. The tower T-Nut is sprung so the tower stays flat to the pivot arm, which is a great idea, but it's sticky so it requires a little attention to get the tower just right before you lock it down. A smidge too high and you don't get a good seal, a smidge too low and you're loading the hell out of the tower when you go to lock it down. I was going to make a cone with a stacked wavy washer to compensate for the loading but never got around to it.

All the cons are really minor nit-picks. Pretty much everyone, once they sort out their building process, has to learn about and/or tweak whatever fixture they have to suit that process. The same goes for all the mitering tools, throw in curved tubes and it adds a layer or two of how you hold things so they're in phase, planar and unloaded so the lengths come out right without screwing around with them too much.

[Andrew R Stewart]

Welcome aboard! I've owned a few jigs, all now from sources that are no longer around...

The Henrey James Universal was my first real jig and the one I have used the most. It's a flat plate with attachments that slide and pivot about. What I liked about it (I sold it a few years ago) was it's flexibility in what can be made on it. I made a few forks and stems on it as example along with a couple of non bike constructs. Not too heavy and if held in a Part type stand the Universal has enough freedom of movement and access IMO. I see them for sale every so often and usually in the $1500 to $2500 range depending.

My Anvil Journeyman is nicer for just frame work. Easier to setup although I don't have any Anvil made mid tube holding add ons, I have made a couple of my own. It's quite a bit heavier than the Uni. I have it mounted to a Park double arm stand and you can see the stand tilt under the weight. The clamping has it's own tilting range which I agree is nice to have. I don't like the angle driven BB drop adjustment, the Master's more common sliding rear axle holder is more my flavor but oh well.

The other jigs I have used were older "machine shop" made, likely only one or two were made of each type. These tended to be based on a flat plate but also were both limiting in tube diameters and BB shell sizes. One of these I built more than a few frames on and when I rescued it years later I modded the tube blocks to be not dependent on the tube diameters to have all on centerline. There both were all steel units and weighed a ton compared to the largely AL jigs.

Every jig had it's rear end alignment challenges and I have learned better (not best yet though...) to compensate and do the tacking in a certain order with checks at some points. No jig was considered "straight" WRT the main triangle, whether they were or not. I tack in the jig, attain centerline alignments on a surface plate then complete the brazing out of the jig. Access for tacking isn't too bad on either the Uni or Anvil but I wouldn't want the jig to be bench mounted and thus block one side.

One aspect That I considered was the jig's footprint and weight. I have had over a dozen different shop locations and had moved the HJ Uni a few times too many:) Now in a house that I doubt I'll be leaving for a long time so the Anvil's greater space and heft is less the issue. The Uni's ability to break down and store away was nice.

Another aspect is what Sean mentioned in how you go about prepping the tubes. If you like to miter to spec before any jig comes into play the ability to set up the jig and have the spec mitered tubes fit to each other right than the Anvil is the jig I would suggest. I think it's closer to spot on in this respect. If you miter the tubes to fit the rest while they are in the jig the Uni might be easier given it's cool mid tube holders.

I have to admit I had mixed feelings with the Uni's protractor method of setting seat tube angles and the top tube length scale can be confusing (it varies due to head angle changes). The Anvil's lack of a top tube length scale is not an issue at all.

Were I to do it again I would likely choose the Anvil again. I also have their fork jig and really like it too. I made my own fork jig long ago (pieces of it are still being used for other small fixtures) then bought a Bringheli which I replaced a few years ago with the Anvil.

The castor wheeled jig stands are really nice when moving the jig about the shop (I don't have this though). If at all possible I suggest playing with a jig or three before spending the $ for your own. I suspect there are a few builders out there that have a few different types of jigs and would entertain a visit. Doug Fattic is one that I know have a few different jigs for his students to try out.

I pay attention to the various frame building For Sale websites and see jigs offered a few times a year. Recently a seller was offering two jigs at only $500 each. At the other end of the range here's a link to a complete frame building tooling collection https://www.facebook.com/commerce/li...are_attachment I would have no issues with buying a used jig and expect to have to play with and do some add ons to whatever I end up with. Andy

[Paul Jacobs]

It is possible to build a straight frame without a jig. I have stopped building frames now but I built 9 frames without a jig. I made three basic fixtures myself which I modified and developed as I went along.

I never regretted starting that way. I don't have an unused jig to dispose of and my fixtures are in a corner of my workshop, taking up very little space, if I decide to build again.

[false_aesthetic]

I own a Sputnik and agree with Sean's assessment.
I'll also add that I did not know that the hardware would be SAE and not metric. It's a small thing but I am still annoyed by that design decision.

You might also want to look into the Process Frame Fixture from Engin. If I were starting over again I'd probably buy this one.

I strongly suggest checking out forums for people's experience with Cobra + Sputnik. You might not get answers about the fixtures themselves but you'll get an idea about the business you're dealing with.

[VertigoCycles]

I own a Sputnik and agree with Sean's assessment.
I'll also add that I did not know that the hardware would be SAE and not metric. It's a small thing but I am still annoyed by that design decision.

You might also want to look into the Process Frame Fixture from Engin. If I were starting over again I'd probably buy this one.

I strongly suggest checking out forums for people's experience with Cobra + Sputnik. You might not get answers about the fixtures themselves but you'll get an idea about the business you're dealing with.

The SAE issue didn't even occur to me but I hear you. Other than the bolt for the BB, what do you interface with that doesn't have a handle?

I should point out that it would be prudent to check in with Jeff to see if he's updated the fixture for the new-ish super long and slack thing that's been going on with mountain bikes. I've run into the limits on the front end for both HTA and front center length...though I can't recall right now what I did to get around it.

[false_aesthetic]

The SAE issue didn't even occur to me but I hear you. Other than the bolt for the BB, what do you interface with that doesn't have a handle?

Dummy axles. But also the initial set-up/assembly IIRC.
I see this as a friction point that shouldn't exist on a fixture that's so expensive. Jeff has considered almost everything else.
In the real world it's NBD but every time I build a bike I ask "Why are the scales in MM and the hardware is SAE?"



Sean, what are your X + Y limits and when did you purchase your fixture? Mine is about 5 years old now and I have 555mm for both.

[e-RICHIE]

More than anything, a frame fixture will help (sic) ensure your design mimics what’s drawn (assuming it’s drawn.)
However, alignment isn’t one of the features.
Some are better than others and will get you close.
But without an alignment table, one will remain in the dark.

I have a Bike Machinery Hydra from 1983.
A Marchetti + Lange table from a year prior.
And a custom made Sputnik from (iirc) 2018 that was fabricated to have the best features of my Hydra.

One needs to determine one’s boundaries wrt design and precision in order to be in the conversation.

It is possible to build a straight frame without a jig. I have stopped building frames now but I built 9 frames without a jig. I made three basic fixtures myself which I modified and developed as I went along.

I never regretted starting that way. I don't have an unused jig to dispose of and my fixtures are in a corner of my workshop, taking up very little space, if I decide to build again.

[Paul Jacobs]

More than anything, a frame fixture will help (sic) ensure your design mimics what’s drawn (assuming it’s drawn.)
However, alignment isn’t one of the features.
Some are better than others and will get you close.
But without an alignment table, one will remain in the dark.

I have a Bike Machinery Hydra from 1983.
A Marchetti + Lange table from a year prior.
And a custom made Sputnik from (iirc) 2018 that was fabricated to have the best features of my Hydra.

One needs to determine one’s boundaries wrt design and precision in order to be in the conversation.

One of my fixtures is a long piece of steel ground flat stock, checked for straightness against the bed of my long-bed lathe. This has a bottom bracket clamp at one end. I clamp the frame at the bottom bracket, after the bottom bracket has been faced, and by rotating the bar (or the frame) I can take a reference measurement at any part of the frame. The advantage over an alignment table that is horizontal, and usually too heavy to move easily, is that I can use my reference bar held vertically. This eliminates the effect of gravity on the measurements which can be evident with a frame clamped on a horizontal table.

[Mark Walberg]

The BB face is really the prime directive.

I once got his off significantly. It led to a crash on the tack.

[Matt92]

Good morning,

Thank you all for your feedback which is very useful to me.
As e-RICHIE says.
The JIG is not everything and a table is essential for good alignment control.
That said, what's the point of paying for a relatively expensive jig if it doesn't allow for correct alignment?
In this case wouldn't it be better to have a not too expensive JIG? I'm offered a DREW Bike and a table like the Marchetti.

[e-RICHIE]

Good morning,

Thank you all for your feedback which is very useful to me.
As e-RICHIE says.
The JIG is not everything and a table is essential for good alignment control.
That said, what's the point of paying for a relatively expensive jig if it doesn't allow for correct alignment?
In this case wouldn't it be better to have a not too expensive JIG? I'm offered a DREW Bike and a table like the Marchetti.

The frame design is a lot more important than the alignment.
It's what dictates rider position as well as how the bicycle will roll.

There will always be trade-offs.
If you're just starting, I'd recommend focusing on fabrication tasks, learning about frame design, and matching rider morphology with position.

[steve garro]

Good morning,

what's the point of paying for a relatively expensive jig if it doesn't allow for correct alignment?
.

More like what's the point if your brazing skills aren't up to evenly tacking the tubes so that your piece isn't pulled all over the place, especially if you don't have the ability to make good, accurate, tight miters? ?

Really the big thing about retaining alignment is not fixtures but consistency in joining, which is really a multi decade dive into understanding the freeze/thaw cycles of metal.

(Yes a long piece of metal is a fixture / jig as to a great extent as pointed out to me by Ron Sutphin is a LUG as it hold s the tube(s) in a certain position)

This is what alignment is about.

A jig just holds your tubes in what you hope will be the final geometry and to that end I currently have an Anvil after owning a Henry James, a Vulture, a Jim Stein and having used an Arctos.

- Garro.

[steve garro]

One of my fixtures is a long piece of steel ground flat stock, checked for straightness against the bed of my long-bed lathe. This has a bottom bracket clamp at one end. I clamp the frame at the bottom bracket, after the bottom bracket has been faced, and by rotating the bar (or the frame) I can take a reference measurement at any part of the frame. The advantage over an alignment table that is horizontal, and usually too heavy to move easily, is that I can use my reference bar held vertically. This eliminates the effect of gravity on the measurements which can be evident with a frame clamped on a horizontal table.

So, are you depending solely on the miters to hold your angles / geometry?

I get your side by side use of the table, but what about the main triangle angles?

FWIW, yes I agree this is a viable method but I want to know what you are doing and have you ever measured the angles afterwards?

For instance I set my jig with a .25-.5* slacker HT* then why I want to end up with as it always pulls.
Front end will shrink a few mm's as well as the tubes suck into the miters.
Your rear end sucks in 2mm.
All evenly if you are doing it evenly.

- Garro.

[Andrew R Stewart]

I see jigs as being about speed and error reduction, not being about final alignment. I have both a flat surface plate and a jig and if I had to sell off one it would be the Journeyman, not the 300 pound hunk of no moving parts hand scraped steel. If fact I got my flat surface long before I bought my first "real" jig. People get impressed with my Anvil jig mounted on the Park stand but it's the surface plate under it's wood cover that allows for confirmation and/or correction.

I'd like to toss into this ring of possible jigs the classic English "window frame" jig. Being so thin it can store hanging on a wall and usually quite lighter in weight than a keel or plate based jig. Usually laid against a surface (large surface plate being ideal) and the tube, axle and shell holding elements are moved about to mimic the design. The version offered by Doug Fattic is a well refined example of this family with many positioning aids and dimensional features included. One of the cool aspects of this type of jig is the ease of using it to also design a frame based on the rider's fit numbers and a stem and seat/post to mock up with. But this type really works best on a truly flat surface that's large enough to fit the outer framework of the jig, which if a cast metal or stone surface plate will cost a pretty penny and be seriously heavy.

An offshoot of this type of jigging is to have a full scale drawing laid down on a surface then tube supports that can be placed against the drawing's lines. I believe Alex Meade still offers a set of tube supports, Bb shell post and axle post set. (BTW I have used him for one off machining jobs too and can speak well of his character). IIRC this tube support block/tower on paper drawing on flat surface is how Paul Brodie does it in his vids.

The Drew jig and table should be fine. As said before, no matter what jig you get you'll be learning it's quarks and your sequences before the true worth becomes known. Andy

[Paul Jacobs]

So, are you depending solely on the miters to hold your angles / geometry?

I get your side by side use of the table, but what about the main triangle angles?

FWIW, yes I agree this is a viable method but I want to know what you are doing and have you ever measured the angles afterwards?

For instance I set my jig with a .25-.5* slacker HT* then why I want to end up with as it always pulls.
Front end will shrink a few mm's as well as the tubes suck into the miters.
Your rear end sucks in 2mm.
All evenly if you are doing it evenly.

- Garro.

Thanks for your input.

As I said above, I am not building frames any longer. I have never sold a frame although there are at least four people happily riding bikes which I made. My point is that it is possible to make a make a straight frame without investing in a lot of expensive and bulky equipment. All the frames which I built were lugged.

My system was:

1. Draw the frame full scale with pencil and paper on a large wooden drawing board. This was quite time consuming but it gave me an opportunity to rehearse the processes in my head before starting to cut metal. I would also use the large sheet of paper to document the frame build, for example any deviations in lengths or angles from those intended and reasons why I thought that had happened.

2. Braze the seat tube into the bottom bracket shell.

3. Cut the head tube/down tube mitre and braze that joint freehand (with the downtube held in a vice, pointing upwards, and the headtube and lug resting on top with a mild steel bar loosly placed in the head tube to maintain balance).

4. Braze the headtube/downtube sub-assembly into the bottom bracket with fixtures holding the vertical alignment of the seat tube and head tube, the down tube/seat tube angle and the length of the downtube (with an allowance for 1 - 2 mm of movement as you have pointed out).

5. Measure the top tube to fit and cut the mitres. At this stage the angles may be 1/4 deg or so off what I intended so I have the choice of cold setting to get back to
original angles or, what I usually do if everything is very close, just cut the angles to fit what I have.

6. Braze both ends of top tube.

7. Clamp chain stay fixture to front triangle and braze chain stays in alignment.

8. Cut and fit seat stays.

Of course I measured the angles afterwards as well as before and at every stage during.

No frame is perfect. Before I started building my own, the only points of reference I had were the professionally built frames which I owned. The frames which I made were at least as well aligned as any of those and much better than some of them.

[rwsaunders]

I’ve never met any of you folks other than in this virtual space, but I believe that two of you recreational builders are Docs, which doesn’t surprise me given the detail that your day job requires. I enjoy the read of course and the exchange with Steve and Richard.

[e-RICHIE]

I've written often on these issues (related to alignment and the tools we use.)

Some gems from my website.

https://richardsachs.com/downsize-the-fantasy/

https://richardsachs.com/7-20-15/

https://richardsachs.com/the-spree/

https://richardsachs.com/repitition-...entlessness-2/

https://richardsachs.com/straight-talk/

https://richardsachs.com/having-tolerance/

https://richardsachs.com/starrett/

[bulgie]

There is a non-zero chance that you will find you don't actually like framebuilding that much after doing a few, so I would caution against spending kilodollars on a great big piece of equipment that takes up shop space and which is difficult to move or sell when you tire of it.

A generic decently-flat welding table, with some V-blocks to hold the frame tubes an equal distance off the table, will suffice for your first few frames, and has the advantage of also being a welding table!

Watch The Bicycle Brothers movie about the brothers who made Jack Taylor frames for decades. They held the frame tubes down on their flat (?) surface by laying heavy weights on them!

Yes, the marketplace has moved the goalposts, with respect to how straight a top notch frame is expected to be. The Taylors, rather than a granite table, held the frame up towards a window and squinted to determine the alignment. And lots of those bikes are still being happily ridden, no one complaining about the ride qualities of them (that I hear about anyway)

My advice is, after building a few with caveman methods, see if (1) you still like doing it and want to continue, and (2) if you're getting enough sales to justify investing money in getting faster. Some may find the game is more fun with a fancy jig, but it didn't seem that way to me. The jig didn't detract from th fun either, in fact getting new toys is usually cool for a while 'til the novelty wears off, but it wasn't a big game-changer in terms of quality of life. You'll just spend less time on the jigging, and checking, and triple-checking your layout before tacking.

After tacking, the jig's job is done, so all the other tasks are left unchanged. Since laying out the tubes and tacking is small-ish part of the job, most of framebuilding is the same whether or not you have a jig.

And if you do buy a jig, get it used, from some other dope who thought framebuilding would be more fun!