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-   -   Pedal Bush Redesign (http://www.haynes.co.uk/forums/showthread.php?t=6618)

andysredmini 13th June 2011 01:15 PM

Pedal Bush Redesign
 
Hi
I am currently building my pedal box and have a bit of spare time and a new (to me) lathe to play with.
Im thinking of producing a 2 piece top hat bushing instead of the straight through design in the book. Im thinking I will probably reduce the steel tube length by about 6mm and have a 3mm flange on each end of the bushing with the same outer diameter as the tube.

Any thoughts on this? i know its probably overkill but like i said i have the time and a lathe waiting to be used.

I was also looking at the oilite bushings but have told not to bother using them when using a threaded pivot.

Cheers
Andy

davedew 13th June 2011 02:25 PM

Andy,

I changed the design of mine slightly. I used a nylon insert with a stainless steel crush tube. Very similar to the wishbone idea. Works a treat and the pedals operate really smoothly now.

Cheers

Dave

trick-kit 13th June 2011 03:09 PM

It's how 3GE always did it, if your going to do it do it right ;)

TK

flyerncle 13th June 2011 07:10 PM

3GE ones were excellent quality and value.

andysredmini 13th June 2011 10:55 PM

Did you do them like a top hat or straight through with a crush tube?

Andy

Quote:

Originally Posted by davedew (Post 60043)
Andy,

I changed the design of mine slightly. I used a nylon insert with a stainless steel crush tube. Very similar to the wishbone idea. Works a treat and the pedals operate really smoothly now.

Cheers

Dave


les g 13th June 2011 11:11 PM

oh yea top hats are the way
bought an 18 inch piece of acetal off the bayŁ7 and TJ turned them down on our lathe ....simples
oh and we didn,t shorten the tubes we just moved each support out by 3 mm wanted to keep the tube lenght for balance and increased bearing area
cheers les g.
we did post pictures for them on here

les g 13th June 2011 11:33 PM

acetal delrin all the same
the post and pictures were in general discussion
titled todays job was pedal bushes and clevis,s
HTH
cheers les g

davedew 14th June 2011 06:06 AM

I just went straight through with mine.

andysredmini 14th June 2011 09:51 AM

If someone had far too much time what would be the perfect money no object method of pivoting the pedals?
Would it involve roller bearings?

MarkB 14th June 2011 10:21 AM

Acetal etc shrinks after machining/drilling....spooky stuff and will annoy confuse the hell out of you...:D

andysredmini 14th June 2011 12:23 PM

Is the shrinkage enough to worry about?

MarkB 14th June 2011 01:25 PM

Quote:

Originally Posted by andysredmini (Post 60081)
Is the shrinkage enough to worry about?

It is if you want something like a bolt to run through it unless you go over size in the first place...have a play is the best answer really and see for yourself how nutty the stuff is:)

les g 14th June 2011 08:52 PM

Dont worry about him he,s just an old fart. :p
he probably thinks we are talking about teflon ...lol
loads and loads of our plant use modern day plastics like delrin as bushes for pedals and linkages etc and they are out in the sh@t and elements all the time, modern plastics are a bit more stable nowadays.
so use a good quality one.
As for the pivotif you are going to use a bolt use a shouldered bolt so the delrin is not running on threads.
cheers les g

Davey 14th June 2011 09:26 PM

As it happens I`m about to make thebushes for my pedals although mine are top hung. I`ve opted for simple nylon to make them from as it is cheap, hard wearing and with top mounted pedals easily replacedif needs be.

D.

MarkB 15th June 2011 08:50 AM

Quote:

Originally Posted by les g (Post 60105)
Dont worry about him he,s just an old fart. :p
he probably thinks we are talking about teflon ...lol
loads and loads of our plant use modern day plastics like delrin as bushes for pedals and linkages etc and they are out in the sh@t and elements all the time, modern plastics are a bit more stable nowadays.
so use a good quality one.
As for the pivotif you are going to use a bolt use a shouldered bolt so the delrin is not running on threads.
cheers les g

Acetal is bonkers. I spent hours machining stuff when I worked for a motorsport firm at Silverstone only to find the holes I bopped up the spout were undersized yet I used the right drill bit...it seems the speed of the machine and how quick you bop the holes has an affect as well as I never had one hole that was the same.......freaked me out, it was as if some ghostie type changed the drill bit each time i used it.

Facing off a rectangle of acetal in 3 jaw chuck was just as frustrating...:D

baz-r 15th June 2011 07:47 PM

its just because its soft and flexible think of trying to drill a hole in a block of rubber :confused:

les g 15th June 2011 10:45 PM

Quote:

Originally Posted by MarkB (Post 60126)
Acetal is bonkers. I spent hours machining stuff when I worked for a motorsport firm at Silverstone only to find the holes I bopped up the spout were undersized yet I used the right drill bit...it seems the speed of the machine and how quick you bop the holes has an affect as well as I never had one hole that was the same.......freaked me out, it was as if some ghostie type changed the drill bit each time i used it.

Facing off a rectangle of acetal in 3 jaw chuck was just as frustrating...:D

you really should be locked up.....for your own safety......lol
you,ll be using four jaw chucks and trying to self center hex bar next :D
slow and steady wins the race
proper center to start
nice sharp new drill bit nice and slow and all is well
and a reamer helps as well
if you go at it to fast it can pull off centre
cheers les g

MarkB 16th June 2011 09:06 AM

All depends how hard you pedal, some go steady some go hell for leather:)


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