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The garage frame building journey

Leafy

Monkey
Sep 13, 2019
542
350
My eyeball online engineer analysis says that the wimpy little ball screws are going to be the weak point. They are going to windup under any real load. But the machine is probably capable enough to make new motor mounts and bearing blocks if you wanted to turn it into something more sufficient. Well that and the high speed low torque spindle motor. Your not exactly going to be able to chuck up a 5" face mill, just small tools spinning fast. It has feedback on the spindle motor, surprised it doesn't seem to support rigid taping, unless I am missing something.
the ball screw doesn’t look that small, only a few mm smaller diameter than a similar length screws from a real vertical. The 8k spindle at only like 2hp kind of is lame but most of the stuff I would do I’d rather have the rpm than the torque, especially with the less rigid machine. No rigid tapping kind of sucks, but if I know where the spindle position is written I can just write the macro to do it.
 

lobsterCT

Monkey
Jun 23, 2015
278
414
Negative, a front triangle will not fit. The idea is to weld up subsections that do fit, then connect them with carbon fiber after heat treating. Hopefully, it will be more like an atherton glue job, than a pole glue job.
 

lobsterCT

Monkey
Jun 23, 2015
278
414
Well, thank you Sir. Its still just an idea at this point, and it will take a couple months yet to really see if I can do it or not.
 

shirk007

Monkey
Apr 14, 2009
499
354
Look forward to following the process.

Atherton's teaser a new bike coming that possibly has cnc lugs.

I think Cadex did welded aluminum lugs with bonded carbon tubes way back in the day.
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
15,827
13,063
Look forward to following the process.

Atherton's teaser a new bike coming that possibly has cnc lugs.

I think Cadex did welded aluminum lugs with bonded carbon tubes way back in the day.
I thought they had to use printing to get the complexity of the double lap (or whatever they're called) joints?
 
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Westy

the teste
Nov 22, 2002
54,232
20,015
Sleazattle
I thought they had to use printing to get the complexity of the double lap (out whatever they're called) joints?

Although not simple, that could be machined from aluminium. I thought the 3-D printing was about being able to easily create custom geometry. Cut tubes, print lugs, glue up.

But it all seems kind of gimmicky to me considering the end results. A friend of mine has the AM150 and the frame probably weighs close to 10lbs. You can do that a lot cheaper with a custom steel bike and they just offer a lot of different sizes, nothing really custom.
 

lobsterCT

Monkey
Jun 23, 2015
278
414
Oh I think you can do it! Just get some tubes of dp420 and you’re off, right?

If dp420 is one of the scotch weld variants, then no.

the scotch welds have the best shear strength of epoxies I looked at, but all of them have very low peal strength. For a design like atherton with the "double lap" or whatever they call it, scotch weld would be the ticket, but my lugs will be simpler, and need peal strength in the epoxy.

I went with one made by an American company called Lord Adhesives.

mcmaster.PNG
 

iRider

Turbo Monkey
Apr 5, 2008
5,648
3,089
@lobsterCT That looks pretty sweet!

I ran out of Argon so I did another project I’ve been meaning to attempt for a while.

I made a linkage for my emoto yesterday. It’s my first time trying to make a linkage at home. I have had friends make them in the past for me. The stock link and shock used to top out AND bottom out while still being harsh. I tried reshimming an RC4 and an Ohlins shock with suboptimal results so I wanted to try a lower leverage ratio and less regression than the stock linkage.

Zero real engineering went into this and I just put the things where I thought they should go. Top link designs have problems and you can only choose where you want them, ime. I have worked with those in the past and have some experience with the limitations. The packaging will limit how much progression I can get and how low I can get the leverage ratio, I think.

A bike industry engineer friend came over last night and we figured out what I should do for v2. Here‘s some pics.

Here, I used the horizontal mill to drill the holes for the pivot points and square off the bandsaw cuts.
View attachment 185688

Boring head for bearing seats.
View attachment 185689

getting there.
View attachment 185690

I’ll make them look nicer when I like the curve. I’m thinking that in addition to a lower leverage linkage, I need to make a longer stroke shock with the body of a 10.5” rc4 and the 76mm fat shaft. I think that plus an extender and then lower leverage ratio linkage will get me in a useable range. That’s my theory anyways.

View attachment 185692

The bike felt so much better and it’s not topping out but it’s still a bit over leveraged, imo. I’d like to come down a bit so I’m not on such a heavy spring.

I also used a shock extender to try and shift the curve towards the progressive side and avoid that regressive end.
View attachment 185694

With an Ohlins cart in the fork and this shock and linkage it feels so much better. Hopefully the 2nd link will cure the last issues I have with the bike. And if not then I’m enjoying learning about this stuff.
View attachment 185695

Vague direction of the one I’d like to make this weekend. Not to scale, haha.
View attachment 185691

@shirk007 You inspired me with your links. I was going to get my friend to make these. Thanks man!
Nice work! So you also put a longer stroke shock in it? Why did you get away from the upper/back shock bolt hole? Looks like you used it and this should be the most progressive one, or?
 

buckoW

Turbo Monkey
Mar 1, 2007
3,777
4,700
Champery, Switzerland
@lobsterCT Sounds good!

@iRider I ended up there on the highest and most rearward hole but in those photos I hadn’t gotten around clearance issues, yet. I was working through it and that wasn’t the end goal. I’m trying to lower the leverage ratio and increase the progression. With max progression I had a too high leverage ratio making a 650lbs spring feel too soft. I changed some pivot points and managed to come down to a 600 without bottoming and the compression and rebound adjusters are now in a useable range.

I took the body off of a 267 and mated it to a 240 to make a 255x75 with an extender to get the progression and lower the leverage ratio. I’m very happy with the results. Working compression and rebound is much nicer! Here are some pics.

408EBCE4-A496-4AF6-A4CD-ECF40D595ACD.jpeg


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DB5C74D4-850B-407B-9830-8FC31F43E1B4.jpeg
 

slimshady

¡Mira, una ardilla!
Soon I might have a little project to add to this amazing thread. I dreamed of building a dirt jumping frame about twelve years ago, and that little dream brought to my life one of my best friends, the one who has the bike shop.

Today we started cutting the dropouts, and I can't contain the excitement I feel.

IMG_20221207_220314_083.jpg
 

buckoW

Turbo Monkey
Mar 1, 2007
3,777
4,700
Champery, Switzerland
Soon I might have a little project to add to this amazing thread. I dreamed of building a dirt jumping frame about twelve years ago, and that little dream brought to my life one of my best friends, the one who has the bike shop.

Today we started cutting the dropouts, and I can't contain the excitement I feel.

View attachment 185957
That’s awesome! I’m looking forward to seeing what you come up with!
 

slimshady

¡Mira, una ardilla!
Thanks guys! I have been scavenging parts for this little project for over a month now. The idea is to use as many standards from the BMX world as possible, so another friend is machining the headtube for an integrated headset and the BB shell to accept a BMX Mid BB. It's going to have BMX hubs too, although with 26" wheels.

We are making v0.1 out of straight gauge 1.2mm 1045 tubes as 4130 is really expensive down here, but once we have the building details sorted out I'll surely be on the hunt for a set of 0.9 chromoly tubes, butted if possible.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,777
4,700
Champery, Switzerland
Thanks guys! I have been scavenging parts for this little project for over a month now. The idea is to use as many standards from the BMX world as possible, so another friend is machining the headtube for an integrated headset and the BB shell to accept a BMX Mid BB. It's going to have BMX hubs too, although with 26" wheels.

We are making v0.1 out of straight gauge 1.2mm 1045 tubes as 4130 is really expensive down here, but once we have the building details sorted out I'll surely be on the hunt for a set of 0.9 chromoly tubes, butted if possible.
You could harvest the headtube and bb out of an old bmx frame too? I can send you tubes if you’d like. I have extras at home. They all fit inside each other (31.8,35&38) so the package would be a single tube. Let me know if that’d be helpful.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,777
4,700
Champery, Switzerland
This dood is making loads of cool shit. We have lots of friends in common and ride in the same places but haven’t met in person yet. Check out his latest mutant.
He calls it the Ghettoblaster


CD82C3E2-0F94-4932-BC23-B215C33698C3.jpeg


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Nice!
D75957D3-7348-4B37-8898-D3C0C16ADEB9.jpeg
 
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buckoW

Turbo Monkey
Mar 1, 2007
3,777
4,700
Champery, Switzerland
I managed to regrind my seatpost reamer on a belt grinder with a 3m Trizact belt and an angle table. It worked great.

429948FB-824E-4A3C-8AF3-025F3FFE727A.jpeg



38F9265F-CC67-43CF-A57F-058ADB498875.jpeg


Now that I had a working seat tube reamer I made some progress on a seat tube assembly.
Some pics from yesterday.
2B44F447-A6E5-4550-824D-014B51828807.jpeg


4E1DEE54-E40A-493D-868B-89641DF1E011.jpeg





F1300519-05A9-434A-8D4F-E9CC183F24BD.jpeg


I’m out of gas so that’s it for now.
 
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slimshady

¡Mira, una ardilla!

sikocycles

Turbo Monkey
Feb 14, 2002
1,530
772
CT
Front end mitered. Now clean and tack.
I go it by Headtube bottom. I know the distance from center of BB to top of the jig. Add the amount for the piece that holds the tool and then that minus what bike cas give me and set the Headtube bottom. I use the TT length for the distance
 

rideit

Bob the Builder
Aug 24, 2004
23,058
11,300
In the cleavage of the Tetons

sikocycles

Turbo Monkey
Feb 14, 2002
1,530
772
CT
Are you going to use a smaller diameter tube and go through for a one piece pierced design or two tubes looking like one continuous tube? Gonna be sweet!
Yes it is a 19mm or 16mm tube. Still deciding on size. Asfor pierced I am still deciding. Not sure my trigonometry is up to it but will decide soon.