[HaveFaith]

Thanks, Yea I forgot the usefullness of the gboxx's case as a structural element, like an engine in a motorcycle.
Quick Q on the parts you got waterjetted. Did you know the person doing this for you or did you have to get quotes from a private company with a waterjet machine? If so was it easy to get a quote on such a low quantity of parts, and if you don't mind me asking, what was the cost? I'm currently designing something that will have parts that can be waterjetted and I'm just trying to test the waters.

Good job with the frame, Its seeming like more and more people are making their own stuff recently with the advent of software like solidworks (sure has helped me) and cnc becoming cheaper. I'll be making something soon myself, stating with a HT just to get my welding on mitered tubes down pat. Also good job on posting this, try and keep up with the tread, we could use more step by step threads on this topic, and you arent exactly going down a paved road with your design, so it will be cool to see all the problems and how you solved them. I'm hoping to make an "open source" style thread in the next year were ill try and post everything on my own DH frame as well.

For the waterjetting, we are lucky enough to have one in house and at our disposal. I do know what we charge however, and since waterjetting is one of the most expensive machines to run and maintain its not cheap. However, it does get a lot done for the given amount of time. For example, the upper gearbox mounts took about 10mins each to cut out of the billet for a total time of an hour twenty (2 per bike, 3 frames, a couple of extras). The jet costs about $50 an hour to run and I believe we charge some where around $100 or bit less an hour. Its worth it for thick pieces (up to 6" thick steel!) removing a lot of material. Sometimes we get lazy when things could be fabbed by hand, but it really is a convenient machine.

For the open source style thread, thats what I was going for. I wanted to post all info that anyone could want as well as honestly attend to any comments or criticism. I feel like the bike industry is very protective over pretty simple ideas and its not warranted. I will definitely try to keep this through the production as well as testing. Thanks for the words...

 

[HaveFaith]

Honestly, I've never built any 7005 weldments. I've done them out of 6061 and haven't had too many issues with distortion.
I do know that 7005 bikes are artificially aged and solution heat treated. If you only do natural aging, I assume you are sacrificing some strength. If you design accommodates the lower strength, then you should be golden.
7005 is pretty rare outside of bikes. I've never been able to source the billet. (and I'm a machinist). I've only ever seen it sold through bike building companies.

We definitely started realizing it was hard to get 7005 once we started shopping for material. What is weird however, is that prices arent much different than 6061, its just really tough to find all the different thicknesses etc. We purchased material from a frame supply company out here in CA. We will be placing the frames in an oven to age them, just not quite the temps for T6 etc. I believe you are correct in saying its not really used outside of bikes. Its tough to even find info on the stuff.

Its possible for future projects we use 6061, once we have a better grasp on the processes, for this one it seemed a bit easier to use the 7005. Thanks for the knowledge sharing!

 

[unskilled]

have any idea how you are gonna price this thing? I know that has been an issue with alot of gearboxx frames has been the cost. You gonna pass on any savings to the little guy?

 

[yuroshek]

that thing looks pretty cool. id like to see it all built up, so stop writing everyone back and build it up. lol. good luck with the build, o btw im about 165 too. so if you need a test dumby im all about it.

 

[ChrisKring]

You can buy a lot of metal on ebay for projects. Most of it is scrap peices that a fab shop has left over from a project. However, it is still more valueable than taking it to the scrap recycler so they put it on ebay. There is no 7005 on there though. Lots of 6061 and 7075.

As far as cutting options, look at Thomas Register for a local waterjet or laser cutting source. I used to do a bunch of small jobs like that at my previous employer (10 years ago). We has a 3500 watt laser that would cut 1"+ steel and 1/2" aluminum. The typical charge was $100/hr plus $90 for set up. I'm sure it's more now. The setup charge was to convert a cad file to g-code and load it into the laser. I would do one part if someone wanted to pay for it. Get yourself a drawing or cad file and call up some local companies advertising. Just know that you will have to machine any critical surfaces or holes to meet tight tolerances. I typically cut holes and reemed them to size for my special projects (bash guards, etc).

there is some software that estimates part cost too. I think it's emachine or something like that. I'd go with the local option but if your just screwing around it seems like a good package to learn with.

 

[LMC]

You can buy a lot of metal on ebay for projects. Most of it is scrap peices that a fab shop has left over from a project. However, it is still more valueable than taking it to the scrap recycler so they put it on ebay. There is no 7005 on there though. Lots of 6061 and 7075.

As far as cutting options, look at Thomas Register for a local waterjet or laser cutting source. I used to do a bunch of small jobs like that at my previous employer (10 years ago). We has a 3500 watt laser that would cut 1"+ steel and 1/2" aluminum. The typical charge was $100/hr plus $90 for set up. I'm sure it's more now. The setup charge was to convert a cad file to g-code and load it into the laser. I would do one part if someone wanted to pay for it. Get yourself a drawing or cad file and call up some local companies advertising. Just know that you will have to machine any critical surfaces or holes to meet tight tolerances. I typically cut holes and reemed them to size for my special projects (bash guards, etc).

there is some software that estimates part cost too. I think it's emachine or something like that. I'd go with the local option but if your just screwing around it seems like a good package to learn with.

www.fairing.com is a good spot for 7005 tubing. they have a good range of butted tubes too, indeed there good for all sorts of bike related components, pre threaded BBs, head tubes, seatstay/chainstay bridges etc... they dont seem to mind small sized orders either.

 

[HaveFaith]

www.fairing.com is a good spot for 7005 tubing. they have a good range of butted tubes too, indeed there good for all sorts of bike related components, pre threaded BBs, head tubes, seatstay/chainstay bridges etc... they dont seem to mind small sized orders either.

Bingo! Thats where we got stuff through...

 

[ChrisKring]

www.fairing.com is a good spot for 7005 tubing. they have a good range of butted tubes too, indeed there good for all sorts of bike related components, pre threaded BBs, head tubes, seatstay/chainstay bridges etc... they dont seem to mind small sized orders either.

Good info there. Pre-threaded BBs and pre-reemed head tubes would save someone building just one frame a ton of cash rather than purchasing the tools to do that. Some better bike shops have the tools. However, many shops don't know how to use them and the tooling is in bad condition.

Spruce aircraft has a bunch of materials that would be good for frame building. Also, there is a very active frame building email discussion group that is a good source of info. One of these days I'll have a workshop big enough to build some frames for myself.

Very cool that your sharing your build progress though.

 

[HaveFaith]

Unfortunately, since we are doing 1.5" head tubes, we have to machine the bar stock ourselves. Though they do have stock that is pretty damn close to size. Also, with gearbox, no need to worry about tapping the BB, just need to ream the mounting surfaces (which wont necessarily be an easy job).

 

[EVRAC]

You'll want to use an adjustable boring head for the mounting surfaces. It will cut on location even though there's only material on one side. A reamer will kick over an make a big mess unless you use a jig with guide bushings. Depends if you're going to do it on a CNC (bore) or manual mill (bush). My 2cents.

 

[HaveFaith]

You'll want to use an adjustable boring head for the mounting surfaces. It will cut on location even though there's only material on one side. A reamer will kick over an make a big mess unless you use a jig with guide bushings. Depends if you're going to do it on a CNC (bore) or manual mill (bush). My 2cents.

Cool, thanks for the thoughts! This does seem like a good way to do it. The plan was to have a steel guide plate clamped top and bottom with the high tolerance bolt pattern machined into the plates to act as a guide for the ream. Your method however, seems pretty straightforward though.

Update on some machined headtube pics:

This is the headtube for the proto, so it will probably be a bit heavier than the final frame's. We got some help from an experienced machinist here and it was a bit of a pain to setup the eccentric chuck in the lathe. Turned out nice though!

 

[ChrisKring]

Could you design the parts so that machining could be kept to a minimum? If you set up your datums correctly, you might only need to ream the mounting holes and align the rest during welding in the jig. That way you would not need to use the boring head.

A lot of people are afraid of GD&T. However done properly, it will give you more tolerance without compromizing the function.

 

[Curious_George]

I'm always confused with the difference between CNC[Computer Numeric Cutting...i think] and machining...unless its the same thing...I know CNC is made in a Cubed machine with a bunch of controlos and a water jet....but basically CNC is just a more technologically advanced way of machining???

 

[ChrisKring]

cnc = computer numerical control

basically, just a computer driving the mill/lathe/waterjet/etc rather than a human. It makes for easier and faster machining than setting up in a more traditional method. You can still do radius' and rounds by hand using a rotary jig. There were a lot of parts machined before CNC.

 

[EVRAC]

Add a computer control to a mill or lathe and you've got it. (Computer Numeric Controlled) It used to just be "NC" when they first started using paper tapes with holes like punch cards. Old school.

 

[EVRAC]

you beat me to it.

 

[HaveFaith]

Could you design the parts so that machining could be kept to a minimum? If you set up your datums correctly, you might only need to ream the mounting holes and align the rest during welding in the jig. That way you would not need to use the boring head.

A lot of people are afraid of GD&T. However done properly, it will give you more tolerance without compromizing the function.

For all intents and purposes we are going to try and keep finish machining down. For now, our plan is to pretty much finish everything, weld, align, age and then finish the mounting surfaces. These surfaces are really high tolerance, and Im pretty sure the frame will at least move a little. We dont even want to be .010 out on these things. Though since this is our first build, it may turn out that it doesnt move too much and we can skip that final step and ream while it is in our weld tool.

All the tips and insight are really appreciated, and I hope it really helps others out there get a good grasp on how you can build a frame. We are rookies at frame building, with decent background knowledge in machining and engineering, so we are learning with the rest of everyone also.

The headtube was done by hand, by the way in case some were wondering.

 

[buildyourown]

Please keep us posted on your progress. I'm really curious to see how your 7005 works out with only natural aging.
I've been toying with the idea of doing an aluminum frame and this could be an option.

 

[HaveFaith]

All frame material is in. Hopefully we will have a decent amount of machine parts finished this weekend. We have some extra scrap material so I think we are going to do some weld tests, especially for the thicker sections meeting the thin wall tubing.

Work has been crazy the last few days so Im hoping to get back into it this weekend.

 

[HaveFaith]

G-boxxes have arrived today and the steel CNC machining is complete (AL by end of week). Have started building frame jigs for welding this week. Hopefully still on track to finish before the otter! Will post some detailed pics tonight...

 

[WODIE]

How much does a gearbox weigh? I was toying with the idea of making at least an 8" travel bike (not gbox) similar to the sx trail and the biggest issue i was running into is where to place all your pivot points.

 

[Hack On Wheels]

I must say, I would love to see what jigging you come up with. Fascinating project, I hope it works out well for you!

 

[HaveFaith]

Hey guys, sorry for the delay. Ive been pretty busy with work as well as working on parts for the bike, but this post should have some pretty good meat to it.

I went by the machine shop yesterday and was able to pick up all of the machined 4130 parts yesterday. Everything looks really good, clean and within tolerances. Only 2 scrapped parts also, which is always nice (lots of spares!) Also, we anodyzed the bell cranks, black for the time being because it was cheap and fast (free and 2 hours). We have been working on the tooling for the rear swingarm and that is pretty much done. We will be welding up the swingarm and the seat stay tonight, and doing some test fitting of components. Over the weekend I hope to finish up the main frame jig and get to that early next week, to finish by wednesday night!

Anyways, heres some pics. The last is of the waterjet getting ready to cut a tooling plate. Shout with any questions/feedback!

 

[ire]

Damn, you guys are moving pretty quickly! I'll be stoked to see the final product

 

[jonKranked]

things are looking good yo! any chance you could weigh the g-boxxxxxxxxxx for us monkies??

 

[HaveFaith]

things are looking good yo! any chance you could weigh the g-boxxxxxxxxxx for us monkies??

I'll try to get a weight on it this weekend. Should be no problem! Im really excited to get this thing done and ridden!

 

[jonKranked]

I'll try to get a weight on it this weekend. Should be no problem! Im really excited to get this thing done and ridden!

Killer! Any chance I could come ride it too???

 

[HaveFaith]

Im more than interested in giving people test rides if they are ever around! This first frame will be a prototype with a couple more built with more dialed stats.

 

[jonKranked]

Im more than interested in giving people test rides if they are ever around! This first frame will be a prototype with a couple more built with more dialed stats.

Just out of curiosity, where are you located? I'm trying to find out how feasible it would be for me to test ride it

 

[cesar_rojo]

Just stupid question, Where are the bearings allocated?

I have posted a few things over in the gearbox bike thread saying I have been designing and getting ready to build a dh race bike utilizing the g-boxx2 and making it sub 40lb for a full build with my buddy Ryan. I figured its at a point that people could check it out, parts are being made and we are getting ready to start building tooling.I feel that 40lb is the threshold where if you can make a gearbox bike this light, it is going to be easier to accept by the general DH race public. Super low CG and unsprung weight are big bonuses and I have a feeling this thing is going to be super snappy and ride much lighter that it is. The specs are as follows:

HA: 65.5
Eff. Top Tube: 22.38
BB height: 13.75
Travel: 7.25
Chain stay: 17.38
Wheel base:45.25 (full droop)
Target frame weight: 7lbs with hardware, no shock (optimized for 165lb rider)
Integrated seat mast

Ive designed this bike a little less slack, but with a decent length top tube (for me) to try and keep the wheelbase a bit longer for stability at speed, but also the rider CG further forward, to natural weight the front end for cornering. The rear end is 4130 steel and the front 7005 AL. I did this to stiffen up the rear end, as in the given volume, you can make the stiffness to weight much better with steel. If you have any questions, let me know. Here are some pics:

 

[dcamp29]

what happens when your cranks explode? you have to order from gboxxx?

i'm not saying those look weak, but stuff happens.

 

[HaveFaith]

Just stupid question, Where are the bearings allocated?

Im using IGUS plain bearings in all the pivot points, with the excepion of the massive roller bearings that are located on the gearbox.

As for the cranks, yes they would need to be replaced by G-boxx. However, I have never seen a stouter set of cranks, especially considering the hollow axle that these guys ride on, probably around an inch inside diameter. They are going to dwarf whatever pedals I put on the thing....

Now, on to the good stuff. We got a good amount of welding done tonight! Seatstays and chainstays (swingarm) were completed and both look really good. They are definitely quite stiff.

 

[dirtdigger]

looks pretty sweet man, what size tube are you using for the seat stays?
i'm guessing thers is not enugh room for the box chain stays to go right up to the main pivot?

 

[HaveFaith]

looks pretty sweet man, what size tube are you using for the seat stays?
i'm guessing thers is not enugh room for the box chain stays to go right up to the main pivot?

The seatstays are 1/2" x .035" wall tubing. Chainstays are 1" x .5" x .035" wall and you are correct, there is not enough clearance to the box for the tube section to continue to the pivot. Still going to add a couple of doublers to the chainstay for piece of mind. Going to do some hand fab today, including cutting AL tubing and preparing material for the beam section where the shock mounts. Also have to finish designing up the frame jig.

 

[ianjenn]

Looking good man!
AWESOME...

 

[Lollapalooza]

That looks like it's really coming together. I can't wait to see the final product.

 

[HaveFaith]

Thanks for the kind words guys. Will be working all weekend to make it happen for Sea Sloth next weekend. I will keep the updates coming...

 

[allsk8sno]

i hope you paint it loud!!

as an engineer i hope to someday design/build a bike...though nothing as ambitious right off

 

[HaveFaith]

i hope you paint it loud!!

as an engineer i hope to someday design/build a bike...though nothing as ambitious right off

Going to leave it raw so you can see the contrast between the dissimilar materials. Should look pretty nice all polished up...

As for the design/build comment, the sky is the limit! This project was a pipe dream 3 months ago, its amazing what can happen when you work hard and plan accordingly

 

[Buzam]

Looks like an awesome project, you guys sure have put a lot of time any money into this. I have to respect that. I can't wait for the next update to this thread.