Mountain Bike Reviews Forum banner
1 - 20 of 29 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter · #1 ·
Hey Guys,

I've been lurking for a while and I'm committed to getting tooled up enough to build some nice frames for myself. I'm a big old Clydesdale with a monster inseam of about 38.5"-39" measured using the very narrow book between the legs method. This is on flat ground and back to the wall with no shoes. That was about as high as I could get a 0.375" thick book up against the bone with my feet separated by about 3" in the middle.

After doing a little bit of math and research I've confirmed that the 175mm cranks I've been riding on are just too short. Thats what my gut feeling has been since about '99 and I just got a set of 200mm cranks to test the theory. They make a huge difference in comfort. However, my 280mm BB height could defiantly be optimized for longer cranks. Its not a huge problem but I'm a mechanical engineer and building a bike gives me something to think about other than custom trucks/cars which I deal with all day long at work.

Only problem is I'm not tooled up for building bikes and I need to get a couple things. My Power Mig 200 is a bit too big and crude for building a bike. I would really appreciate some input on the subject from the likes of the guys who are here and build stuff in real life. I learned the hard way myself many many times and its always nice to have an old pro give you some insight.

I've already searched and looked at every single picture and link over at www.pvdwiki.com under the frame building section. Thanks for posting the wiki site! I love it. I'm going to build something very similar to the TIE Advanced X1 and maybe add a bit of the Monster Cross flavor down the road with an 80mm cannondale suspension tube.

I'm in the market for bike specific tools which is what I'm looking for advice on. I've already got the standard machine shop stuff like lathe, mill, big MIG welders, etc. Having the flexibility to fabricate from a small garage and access to only 110V power will influence some of my thinking. Spending 12-14 hours at the real shop working on product design and my own projects can be hard. Its really nice to do some work from home where I can relax and have a different environment.

1. TIG Welder -- The Dynasty Holy Grail Dilemma

So, I've always wanted a Dynasty 200DX. I consider it to be the holy grail of TIG welders. I also like the Thermal Arc 185 TIG but it only runs on 220V. I really like the 110V option and it gives a lot of flexibility. My question here is can I live with a Miller Maxstar 150 STH? I'll have the HF start for thin wall tube and I'm not going to build an AL bike unless I design a custom full suspension bike... which isn't going to happen anytime soon. I don't want to mess around with an old transformer based TIG like a syncrowave 180 or something even if they are pretty cheap these days. Takes up too much space and 220V. It would have to live at work and not tucked away in a small box in my garage.

2. Tacking Fixture / Jig

Henry James is just half an hour north of me and they are great people. Anvil has a radical product that I really like. However, both of these jigs are just too much for a guy who wants to build maybe 5 bikes a year. I would buy the Anvil journeyman or HJ if I was going to start cranking out product. This leaves me splitting my hairs going back and forth between a home built jig out of 8020 AL extrusion like the one linked here

http://www.instructables.com/id/The-simplest-bicycle-framebuilding-jig-I-could-com/

or I can break down buy a less expensive fixture like Bringheli as shown here

http://www.bringheli.com/components.html

I can always design something out of 8020 or maybe some blanchard ground square stock but it seems like a brand name fixture might have better resale value if I want to part with it. If the Bringheli is only about $1300 and I end up with a bunch of time plus $500 into a home built 8020 fixture maybe there is some value going off the shelf?

3. Alignment / Inspection / Fixture Table


We have some blanchard ground 4' rounds at the shop but they are mega heavy 1.5" or 2" thick plate rems that we had ground after we got them. They are left over from some ship building in San Diego and one of our vendors gave them to us. Then we had them ground on both sides and now they are sitting out in the yard collecting a bit of rust. I bet I could get my boss/owner to sell me or trade me one pretty cheap. However, it is really damn heavy and I'll end up using my diesel truck and an engine hoist if I ever want to move it around. The other option is to get a 0.75" or 1" thick hunk of aluminum tooling plate which has very high tolerance right from the mill. I could also get some 6061 blanchard ground on one side. The tooling plate is good to about 0.005" and blanchard ground is about 0.002". They are almost the same cost for a 4' x 3' hunk. I think the tooling plate is just a bit less expensive. The AL would be easy to move and I can setup a stand for it with casters out of 8020 and make it really easy to deal with. At the same time I'll have every bit of $700-$800 bucks in a nice 4' x 3' table. I'm also thinking it might be nice to find a steel rem in a thinner section like 0.5" and have it ground. Maybe a good balance between light weight and a bit cheaper.

It looks like most guys use some sort of a surface plate like this, be it granite or otherwise, and a height gauge / dial indicator to check the frame after welding. The BB shell would be clamped to the table as the origin. Then use a big breaker bar to tweek the frame one way or another. Check with a dial indicator and move on. Truth be told I'm going to have a few iterations with the basic geometry before I worry too much about tolerance. Being an engineer I'm tempted to have it thrown on my buddies Brown and Sharp CMM but I've got to be realistic here and deal with the fact that I don't need +/- 0.0001" to have a great ride.

4. The Great Braze vs. TIG debate


I've got O/A and I can braze no problem. I like TIG for some reason I can't put my finger on. Even if I TIG the frame I'm sure I'll end up brazing on alot of little stuff here and there. Maybe that stuff could be TIG welded and I can do without brazing for the most part. Brazing is pretty cheap to get into but at the same time I like the idea of TIG welding because I'm much more familiar with the fixture / tack / weld / inspect procedure. I guess I can tack weld it with O/A and steel filler in the jig. Then pull it out to braze the fillets? I'm sure a braze will be more than strong enough when done right... just seems like fooling with the torch can be more work than a nice little TIG weld... that and its always fun to have a manufactured reason to "need" a TIG welder.

Well... thats all for now. Thanks guys for any input you've got... I'm going to go actually ride a bike and stop obsessing over building one!
 

·
Premium Member
Joined
·
7,491 Posts
Kudos!

Someone actually did research before posting! Unprecedented! Gold star!

I am about to leave for a vacation, but here's my brief take:
-Braze the first few. Use what you have. TIG is really only useful if you want to build lots and lots of frames, IMO.
-Build with an 80/20 fixture or fixtureless (hockey stick style).
-Align on a concrete floor/the stuff you have at work or use a piece of cheap aluminum bolted to the BB. No need to get crazy about alignment for your first few frames.

You will have a much better idea what you want for tooling after you've built a few (ie "man, having that xyz thingie would have saved me 2 days!")

-Walt
 

·
Eric the Red
Joined
·
438 Posts
The usefulness of 80/20 as a frame fixture is limited only by you. It holds pretty good tolerances and can be configured however you want. Marty at Geekhouse has a really nice 80/20 fixture, and he builds plenty of frames on it. Also, I think that Sputnik's new fixture is based on a similar extrusion (Bosch maybe).
As for alignment, you can get a long way with normal stuff like straight edges and squares. Don't forget about the lowly level. I've been clamping the bb shell to the bed of my lathe, and using a high quality torpedo level to tack into alignment. When I put it on a high dollar alignment table, it's right on.
I agree with Walt on the o/a part. If you've got it, use it. Tig is my day job, but I had a torch at home so that's what I used when I started building. I'm glad I did, and my style is developing around fillet brazing. There are even a couple of guys who o/a weld, Jon Norstog at Thursday is the only one who comes to mind at the moment though.
You sound like you have a pretty good head for this already, I hope you post pics when you get going.
 

·
Registered
Joined
·
47 Posts
The Sputnik fixture uses a piece of Bosch extrusion to hold the drop out tower. I would say it is a stretch to say the jig is "based" on it though- the meat of the jig is a piece of aluminum tooling plate.



(By the way, that jig is worth 145 years of ramen lunches- that's a lot of ramen for 5 bikes a year).

Going to the original topic- if you can get/ make a good table and are only doing a handful of bikes a year I would opt for that before any fancy pants (and especially any not fancy pants) jig. You can use it for set up, checking alignment and general layout. Way more versatile (albeit slower to set up) then a jig.

Time is money- if you enjoy building tools it can be a rewarding experience. If you only have a handful of hours a week to "play" it is just a matter of how you like to spend your time- building tools or building bikes. Its a matter of ROI for a professional, it's just a matter of what is fun and educational for a hobby builder.

My suggestion- build as cheaply as possible for a bit and figure out what you like, what you don't and why. Spending money is easy- spending money to solve actual problems in a way that works for YOUR build method and budget is a little harder. Use what you have available then reassess.
 

·
Registered
Joined
·
708 Posts
I think you get a hell of a lot of jig for $1300 with the Bringheli. I build 12 frames/year and have been pretty happy with it for 5 years. I've made a few upgrades and have had Joe make a few upgrades at amazingly cheap prices.

-Joel
 

·
Eric the Red
Joined
·
438 Posts
Winter Bicycles said:
The Sputnik fixture uses a piece of Bosch extrusion to hold the drop out tower. I would say it is a stretch to say the jig is "based" on it though- the meat of the jig is a piece of aluminum tooling plate.
Yeah, fair enough. Admittedly, I only saw it once and was remembering it incorrectly. I do think that the fact that Jeff uses it at all in the fixture means that it holds tolerances well and should be considered as a viable option.
 

·
Registered
Joined
·
47 Posts
edoz said:
the fact that Jeff uses it at all in the fixture means that it holds tolerances well and should be considered as a viable option.
Agreed!

What can't be seen are the massive aluminum blocks, 4 hardened key pins and 4 3/8" bolts that hold it all together. Great materials, but also very solid construction.
 

·
Most Delicious
Joined
·
1,404 Posts
For your first couple frames there are enough things to make mistakes on that jig accuracy is the last thing to worry about. You just need to hold good carpentry tolerances.

Once you've got a few under your belt and you've gotten all the dumb mistakes out of the way then you can start dialing in the accuracy of everything.

If you want a small flat surface, I've seen people do nice things with leftover 9x36 mill tables.

Though since you seem to be familiar with surface plates and the like, you might want to consider strategies where you build right on the alignment table. There was a really great one in these forums a little while back (EDIT: MDEnvEngr's jig, posted below), and there's also Doug Fattic's interesting laser-cut system.
 

·
Plays with tools
Joined
·
4,648 Posts
even though I am on the verge of buying one (used) I think the inverter machines are over rated. If I were going to buy a new Tig machine tomorrow I would probably get a Lincoln precision tig 185, wide range, excellent low amperage control, AC/DC, clean starts and not much bigger than a Dynasty. Not sure about power needs but it is probably limited to <220, sucks to be you.

As far as the alignment table goes I have been using a chunk of scrap granite counter top. Although I don't have any formal tolerances for it I get pretty repeatable results with it. I'm happy with it considing I paid a whopping $75 for enough to make 4 frame sized tables with. I still have enough for one more if you want it.

When it comes to construction methods, obviously a great frame can be made with either method. When it was time for me to start their was no way in hell I was going to braze them together when I spent all day with a Tig torch in my hand. My thought was I didn't need to learn to do something else just to make bicycles. Your comfortable with brazing so if the $3000 you will spend on the welder you mentioned is an issue, 1/10 of that money can buy you a set of torches.
 

·
Registered
Joined
·
118 Posts
edoz said:
The usefulness of 80/20 as a frame fixture is limited only by you. It holds pretty good tolerances and can be configured however you want. Marty at Geekhouse has a really nice 80/20 fixture, and he builds plenty of frames on it. Also, I think that Sputnik's new fixture is based on a similar extrusion (Bosch maybe).
What is nice with 80/20 (or Bosch rexroth) is that you can start with just a few pieces bolted together, with some threaded rods for the main axles, and later improve it with nicer accessories, dropout support, etc, while still re-using the same main extrusion parts.
 

·
Belltown Brazer
Joined
·
693 Posts
Hobbiest here...

Also an engineer. Tried the 8020 and didn't like it. Thought through what I was up against and (with inspiration from Doug Fattic's layout fixture) came up with a simple system to build off of my surface plate. I've built 19 frames now, and see no reason to go fancy jig...though the fancy jig looks much better in pictures.

Tacking is a bit of a pain to get on the back side, but not a deal breaker. One could make their stand offs taller to ease that issue.

I do use a backbone of 8020 for my chainstay/rear end jig. Don't have a pic of that one available. I'll take one someday. I also used 8020 for a fork jig...again no pics of that yet.

The simpler the better. Building a frame can be complicated enough...I think that a lot of hobbiests overwhelm themselves with fancy-pants equipment and get stuck.

B
 

Attachments

·
Registered
Joined
·
47 Posts
That looks great! Right in line with my comment about getting a plate first and going from there (the plate will not loose it's usefulness).

If anyone decides to make their own jig I have three bits of advice- make sure you can check it's flatness (look, another use for a surface plate!), avoid long and flexy arms, and the greater the built in stand off, the greater any build in inaccuracy influences the frame.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #14 ·
thanks for the input guys... Here is what I'm thinking at the moment.

1. Surface plate... I'm going to start by using the blanchard ground drop we have at work or one of the real granite surface plates to align the frame. The drop is just mild steel plate at about 1.5" thick and 4 foot round. Very heavy and it should make a great table. I'll have to build some legs for it at the shop but thats not a problem. Its blanchard ground on both sides to about 0.002" flat which is plenty. I've got a big old Milwaukee magnetic base drill to blast a hole in the plate for a bottom bracket mount. I'm going to turn out a couple bushings that will thread into the BB english threads on the lathe. They will look like a plug on each side and it will bottom out with a shoulder on a faced bottom bracket shell. There will be a hole down the middle. Thread each side into the BB and then clamp everything down to the table using a bolt through the middle. That will locate the frame nice and solid if I want to tweek it with a breaker bar on the table. The steel drop must weigh several hundred pounds so it won't float around if I'm pushing and pulling on a breaker bar. I can make a quick fixture to setup a dial indicator to inspect the frame or use one of the height gauges.

2. Fixture... it looks like 8020 holds a "good enough" tolerance along the length for a shade tree bike builder. There is a local supplier that will deliver it for free. As quoted by the supplier...

Twist per foot of length not to exceed .25 degree and total twist over 20 feet of length not to exceed 1.5 degrees. Flatness .004" per inch width. Straightness 0.0125" per foot length, not to exceed .120 inches over 20 feet of length.

That should be good enough for a first fixture. Most of the other bits I turn on the lathe can be used for a different iteration of the fixture if it doesn't work out for the long run. Part of the fun is just building for the sake of building and I haven't worked a lot with 8020. Sounds like a good reason to order some 8020 and get a practical feeling for what it can do. If I don't like it the 8020 can be re-used to make table legs or something.

3. TIG welder... I really like the little Maxstar 150 STH. Its only 10 lbs and it will run off 110V so I can use it just about anywhere with stick. Its a swiss army knife and I can get a suitcase style package to drag it around. Thats good for my other hobbies... I've been known to stick weld with 3 car batteries and jumper cables when in a bind so this will be a step up. I've got a PowerMig 200 for general fabrication use and I don't really like to change to a smaller wire to run thin stuff... the TIG / stick can fill a void in my tool collection and it won't set me back big bucks if I get one used or keep an eye on eBay.

4. All of this isn't going to happen next week... and thats the fun part. I can pay with geometry and fixture stuff in CAD before I ever get to building. I'm sure this plan will continue to change as I keep kicking it around. My other project is kinda done for the moment so I've got to find something to think about and this project seems to be pretty interesting.

5. MDEnvEng... thanks for the pictures! I like your fixture.. I also like the high quality IPA beer boxes in the background! Seems like people who are into bikes also like good full body beer! I would go this way but I want to to the jig and welding at my place... the big old steel plate requires a fork lift to move around so I'll use it for alignment at the shop... I figure I'll screw up at least a couple frames before I hit the sweet spot so my opinions might change the second or third time around. For the first frame I would rather have cash tied up in a TIG welder rather than a plate when I've got something I can use at the shop for free. I might try the plate method with an AL tooling plate depending on how many months or years I drag this out for... which will help pay for the plate so I don't need to make that investment right away.
 

·
Belltown Brazer
Joined
·
693 Posts
xdpackin said:
but I want to to the jig and welding at my place... the big old steel plate requires a fork lift to move around so I'll use it for alignment at the shop...
Sounds good to me, but remember you're just tacking in the jig. It is handy to have the surface close to where you're tacking and welding to check frame alignment in between steps.

Also, your BB posts dont need to thread into the BB. Seems to me that could pose a problem where you have to chase the threads in the BB often for each alignment check. I think a close-fit inside and aligned off the sides of the BB is fine.

I picked up my surface plate from an old pattern-maker's shop via craigs list. Cost me $100.

Good luck!
 

·
Registered
Joined
·
434 Posts
Xdpackin,
good call on number one choice for using what you have available for a surface plate, chances are it will be nicer than what a lot of guys are using right now anyway. As far as the BB tower goes, don't thread your plugs, just cut them close enough for a slip fit, and focus more on the accuracy of the surfaces that contact the faces of the bottom bracket. No matter how good at heat control you are, it will be a few frames before you are not distorting the bottom bracket shell somewhat. Threading it onto your jig will only prove to be frustrating and potentially fatal to the framebuilding effort.
keep up posted man.
 

·
Registered
Joined
·
3,797 Posts
For a first frame, keep it cheap and simple in terms of tooling an materials.

Buy cheap tubes and dropouts. Chances are that the first frame will be donkey no matter how awesome you think you are. #2 is where you can put more money in, but even though you think "this one is going to be perfect" you will still completely screw it up. #3 is the good one because you have lowered your standards to a more realistic level and you don't screw up the big stuff. They are all awesome to ride because YOU made them.

I think that v-blocks and/or 80/20 on a concrete floor or quality flat surface that you may have available is going to be fine. You may find that someone in your area has a jig they could lend you for a few days. An option not often explored, but there are a lot of jigs out there these days.

Alignment is over rated. Sure it's a good thing, but you can build a few bikes before you have to worry too much about that. Focus more on decent reamers, chasers, and heat sinks first (especially seat tube heat sink).

I like tig even for first bikes. I'm sure you have one you can borrow. It's just so easy to put a tack in and fuss a bit then add another tack. You will still need ox/ace for the brazeone, so work on lining that up. Everybody has this setup so borrow one.

I really think that it's important to get in cheap with minimum investment. You will find what part of the craft you appreciate the most and then you can invest more in ways that will pay you back the most.
 

·
Registered
Joined
·
208 Posts
Wow, lots of good stuff in this thread. I'll add. Use a piece of 3/4 to 1" MDF for your alignment check. Straight edge level criss-cross will verify it's reasonably 'flat'.

+1 on the OA brazing. If you are only going to do frames. However, if you like to tinker, the TIG is invaluable in so many ways. The Maxstar is a good little machine. I'd probably spend the money on the Dynasty. I've been 'out' of the fabrication business for about 2 years now, but I bet I use that welder 3-4 times per month for just about anything you can think about.

For the frame I built a while back, I didn't use a JIG, but I did have an alignment table of sorts. I went to the local scrap metal yard and picked up a 48x36 piece of Aluminum 1" plate for my welding table. It was an old CNC fixture that had been ground flat. This cost me about $50.00, was easy enough to do what I needed to with it.
 

·
Registered
Joined
·
714 Posts
xdpackin said:
3. TIG welder... I really like the little Maxstar 150 STH. Its only 10 lbs and it will run off 110V so I can use it just about anywhere with stick. Its a swiss army knife and I can get a suitcase style package to drag it around. Thats good for my other hobbies... I've been known to stick weld with 3 car batteries and jumper cables when in a bind so this will be a step up. I've got a PowerMig 200 for general fabrication use and I don't really like to change to a smaller wire to run thin stuff... the TIG / stick can fill a void in my tool collection and it won't set me back big bucks if I get one used or keep an eye on eBay.
xdpackin, sounds like you've got a great start and a good plan. I'd recommend (and I've never used the Maxstar 150, so keep that in mind) but you could look at the Maxstar 200 DX and it also is light, small, runs on 110 and does a LOT more than the 150.

Also, I'm building on a flat surface and just finished #3 last night--well, not finished, but pretty much finished. I need to braze in the braces, stick on the disc tab, slot the seat tube, etc., but the hard stuff is all done. It should be ready for Friday S&T. Also, it's been said before, but if you do a search for "WWTP", you'll see how I got #1 done start to finish.

Good luck, you're going to enjoy it I'm sure.
 

·
Old school BMXer
Joined
·
2,695 Posts
pvd said:
Buy cheap tubes and dropouts. Chances are that the first frame will be donkey no matter how awesome you think you are. #2 is where you can put more money in, but even though you think "this one is going to be perfect" you will still completely screw it up. #3 is the good one because you have lowered your standards to a more realistic level and you don't screw up the big stuff. They are all awesome to ride because YOU made them.
You nailed that one! But even before I finished my 3rd, I already found a bunch of ways to improve my process and a few techniques for the next one. But the 3rd has the best alignment of the three (the 2nd has the horzontal dropouts about a degree out of phase - I figured that out for the 3rd).
 
1 - 20 of 29 Posts
Top