OzVMX Forum

Clubroom => Vintage Track => Topic started by: mattsaggus on April 16, 2010, 09:21:43 am

Title: building a press
Post by: mattsaggus on April 16, 2010, 09:21:43 am

Hi all
      The pushing out of jawa big end pins is a bit of a job, i buckled my 25 ton press doing the last and that was only maintenence, not a seize.
What capacity press do you think i need to make to push out stubborn pins?

Cheers Matt.S.

Title: Re: building a press
Post by: Lozza on April 16, 2010, 11:15:08 pm

 The force needed is dependant on the interference fit beteween the crank pin and the crank pin bore. What temp do you get the webs to before starting to press?

Title: Re: building a press
Post by: Freakshow on April 19, 2010, 12:19:47 pm

Do you freeze webs before you press in ?

Title: Re: building a press
Post by: matcho mick on May 03, 2010, 10:25:44 pm

no  freaky,freeze pin going in,my matcho crank has jawa pin,neb rod,went in with nitrogen the 1st time,(overkill i thought :o),poofter to get out but ;D

Title: Re: building a press
Post by: Freakshow on May 04, 2010, 07:41:20 pm

so you heat the webs then ?

Title: Re: building a press
Post by: Lozza on May 04, 2010, 09:51:54 pm

See if you can work it out ::)

Title: Re: building a press
Post by: Curly3 on May 04, 2010, 10:04:48 pm

Just like the constipated mathematician.
Had to work it out with a pencil.

Title: Re: building a press
Post by: Freakshow on May 04, 2010, 10:54:45 pm

well if you think about it if  you heat something expands so why doenst the hole enlarge and close up ? which sends you into having to shring the other in side. 

if you just froze the first part then why do you need to do the other ? lawance all you asked was what temp was his webs > seems arse about.

we freeze bearings yet we heat barrels - i think we should just beat the crap out of everything with a hammer , to make it all simpler. ;D

Title: Re: building a press
Post by: TT5 Matt on May 07, 2010, 07:57:21 pm

some people just shouldn't own tools not even just a hammer,leave it to the people that KNOW how to and how the right tools to match their knowlage,way cheeper

Title: Re: building a press
Post by: mattsaggus on May 24, 2010, 09:51:30 pm

Heating and freezing is all well and good in assembly but my main concern is disassembley of a seized big end.

I used a friends 100 tonne press which obviously did the job, but it had no gauge to tell me pressure exerted to push it through.

Heat and freeze fits are always fun, the bastard either drops straight out the far side or gets stuck half way.     :o

Matt