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Post by jiterbug on Dec 3, 2015 2:16:06 GMT
Any thoughts on custom frames?
The ones I've seen, are tube with welded construction. Lots of Harley based frames which doesn't interest me. Spondon style frames are WAY cool.
My end game for Redemption is to build my own frame. But not welded construction.
Let me explain. I am a machinist. I've done 5 axis, programmer/process planner, program and design with MasterCam, program on the control.
So, my plan is to use aluminum. It won't be one piece though. I can make it in sections, and fit the sections together with ball and socket type features that fit together where the sections meet. So, once the pieces are bolted together, they can't move in relation to each other. The sections would be machined in an I-beam shape for strength.
I don't know if I explained that well enough.
Feel free to comment.
I understand there is going to be safety concerns here, so let's hear the good and bad . . .
Duane
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Post by bigkenxx on Dec 3, 2015 5:57:36 GMT
I'd say have a go , if we didn't experiment we would all still be walking everywhere
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Post by jiterbug on Dec 4, 2015 12:07:49 GMT
That's cool stuff slim. The reason I started this thread is talk about frame ideas so let's have em.
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Post by gsexr on Dec 4, 2015 13:50:06 GMT
As you are bolting them together i guess you wont need a jig......... what about sideway,s movement...  |
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Post by gsexr on Dec 4, 2015 14:48:51 GMT
engine stress ? swingarm twist under load,
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Post by bluedog59 on Dec 4, 2015 17:16:35 GMT
There have been plenty of bolted together frames over the years, many of them in racing. They have been done in both alloy and steel and, if they are designed properly, there is not problem with it. One advantage of bolted together frames is that there is no heat affected zone around welds ( the normal place a welded frame will fail).
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Post by quazi on Dec 4, 2015 20:56:45 GMT
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Post by stellafella on Dec 4, 2015 21:05:11 GMT
 this might be a good book to have a look at mate
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Post by jiterbug on Dec 4, 2015 22:56:09 GMT
Slim. Almost all your examples has crossed my mind as well, except for the complete single sided frame, I need to wrap my head around that one yet. I thought of hanging the suspension off the frame too, that will require some in depth re-engineering.
stellafella, I'm going to look for that book. Thanks
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Post by bluedog59 on Dec 5, 2015 9:15:34 GMT
I have found that the John Robinson book is a little "cat sat on the mat" so to speak, I have found both the Tony Foale and John Bradley books far better. For the real world actual practicalities of building a motorcycle John Bradley's "A technical guide for constructors" volume 1+2 is far better.
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Post by jiterbug on Dec 6, 2015 2:31:48 GMT
Nice. I need to find some books.
Cheers guys.
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Post by tonynitrous on Dec 6, 2015 3:08:25 GMT
I like the idea of a custom frame but my pockets aren't deep enough.
Spondon, Harris, Martek, Egli etc done to my specs would be ace.
Build my own ? No thanks, not for me.
160+hp motor pushing a fat sticky 190 tyre up the road at 150+mph
and grabbing a handful of big radial brakes on an USD front end is
something that I'd leave my frame building to those that know better.
Chops and customs for the sake of being different do little for me,
I'd want something that works well, and I couldn't build that.
I'd still have one if I could afford to get it done right though.
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Post by kokolis on Dec 6, 2015 8:54:49 GMT
The problem with a bolt on construction is that parts have to perfectly fit and where them are bolted together has to be absolute no slak, otherwise the frame will eat the bolts away.
I think the trick was an inner sleeve on the in section and thicker washer on the out both welded iirc
As said its done before, but it needs more time to get it right than a welded frame.
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Post by bluedog59 on Dec 6, 2015 11:09:17 GMT
You'd be suprised at the force a bolted up joint can withstand. The headstock fitting could be a dowelled fit but a number of people have done frames with a bolt on, adjustable, head stock. The Ducati Panigale headstock bolts to the engine along with the rear suspension.
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Post by jiterbug on Dec 6, 2015 14:21:46 GMT
I agree with the point of the bolt being the weak point. As noted above, I would use dowels along with bolts. Also, I would use keen-serts for the bolts, which are stainless steel inserts that thread into the aluminum.
As to the point that inside and outside features need to be a perfect fit, I am in complete agreement. But that is the beauty of designing the whole frame together. And I can machine features to within 0.0005". If the feature can't move relative to each other, they can't wear.
Everyone is making good points. This is great.
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