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Discussion Starter #21
quote:Originally posted by Geeto67
in a motorcycle engine are the forces great enough to actually round out the big end on a Ti con rod?
An XT500 piston is about 1lb, revving 8000rpm causes some 4000g
acceleration to it at tdc, i.e some 1.8kN inertia force is created
("the piston pulls with almost 2 tons"). Everything flexes, titanium
more than steel, so both big- and smallend tend to ovalize under this
load which may cause trouble in terms of seized wrist pin or bigend
bearing. Webs help to minimize this deformation without adding too
much weight.

quote:didn't know about the fatigue...good to know.
Yep, in this regard Ti6Al4V behaves similar as a good tempering steel.

quote: what's the flareout on a machine that has enough strength to cut Ti with just a jet of water? I have to imagine you are in the 10s of thousands in terms of pressure....how far off is the backside from the front side?
Though this machine works with some 3000bar (over 40,000psi) and a
.014 jet, water alone can only be used to cut soft materials as steaks
(no joke, afaik waterjetting has its origins in the food industry),
rubber or plasics. To cut metal an abrasive similar to the one being
used for sandblastig must be added.
The machine itself looks like a swimming pool with a steel grate at
the surface of the water where the workpiece is put on. A kind of
beam hoist carries the jet, which is put down close to the upper
surface of the workpiece and then driven with little feed (depends
on what is being cut of course, we had some 2inches per minute) along
the contour. Doesn't sound much different than a high pressure washer.

Best regards
Sven
 

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Discussion Starter #22
quote:Originally posted by Makr

Cool. I think an I-beam is a better design from an engineering standpoint. What are you going to use to between the rod/crank sides? Maybe leave the outer bearing race wider than the rod?
Yep. I been thinking about an axial guide in the smallend (flanged bronze bushings snuggly fitting between the piston skirt) but
I guess some hundredths excess length of the race will be the easiest and best solution.

Best regards
Sven
 

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Discussion Starter #23
quote:Originally posted by Makr

Cool. I think an I-beam is a better design from an engineering standpoint. What are you going to use to between the rod/crank sides? Maybe leave the outer bearing race wider than the rod?
Yep. I been thinking about an axial guide in the smallend (flanged bronze bushings snuggly fitting between the piston skirt) but
I guess some hundredths excess length of the race will be the easiest and best solution.

Best regards
Sven
 
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