Date: Sat, 14 Jul 2007 12:04:05 -0700
Reply-To: Bob Donalds <donalds1@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Bob Donalds <donalds1@VERIZON.NET>
Subject: Re: exaust removal woes
Content-type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original
I use a shop in Santa ana Ca to do my EDM work mostly on head studs for WBX
engines
Jerry's broken drill and tap they can handle it BUT maybe its time to take
step back and look at the bigger picture
and consider a good used head or a new pair of heads or A fresh longblock
I have any and all of those options available here at the engine exchange
how can I help you
Bob Donalds
Boston engine
508 358 6264
in the shop today and tomorrow afternoon working on my own vans
----- Original Message -----
From: "Evan Mac Donald" <macdonald1987@SBCGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, July 14, 2007 9:04 AM
Subject: Re: exaust removal woes
> The process is usually called "EDM" and should be easier to find if
> searched for that way. Basically, a high-energy arc discharge is used to
> vaporize the metal at the point of the electrode. Kind of like arc welding
> in reverse. Many prototype parts shops use this process to cut metal
> plate, and also to bore small diameter, deep holes. Since there is no
> actual "bit" removing the metal, it cannot break off and get stuck.
> Changing the voltage / amperage parameters allows for better removal of
> different materials. It may be cheaper, though, to get a new head...
>
> pdooley <psdooley@VERIZON.NET> wrote: Even "good" bits will have a heck
> of a time drilling through a tungsten
> carbide drill bit.
>
> The one method I have heard about to do this is spark erosion.
> Apparently some kind of device is hooked up which sends a concentrated
> spark
> through the broken off bit and erodes it away.
> Sounds pretty slick, but that's all I know about it.
> I have never seen it done or know about equipment availability.
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> dylan friedman
> Sent: Friday, July 13, 2007 10:36 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: exaust removal woes
>
> to do it the right way and have it work when you are finished, the head
> should come off and use a drill press and good bits to make a hole for an
> extractor. I have had similar issues in the past. I don't mess with it in
> the van. I pull them and do it so it will last and not make matters worse.
>
> dylan
>
> craig cowan
> wrote: So today my day at work started
> as any would (except discovering the trash
> truck put a sizeable dent in the nose of the vanagon......which will be
> repaired free of charge), and the mecahnics at my work started working on
> my
> vanagon. I popped in from time to time to check the progress. The goal was
> to replace the manifold gasket at cylinder 1, so the manifold had to come
> off as the studs were damaged. Of the 4 bolts that connected to the heads
> and 2 that connected to the collection pipe (1.9L) The collection pipe
> bolts
> came right off, and 3 of the head nuts. One was not so lucky. It snapped
> and
> the mechanic welded a nut to the stud and started backing it out.....it
> was
> working really well....till it broke the stud halfway inside the head.
> So......out comes the tungsten carbide drill bits.......a very accurate
> and
> perfectly executed drilling went horribly wrong when the bit broke off
> flush
> with the head. "You cant drill out a drill bit" boss mechanic said.....so
> over the course of the weekend the entire staff is trying to figure out
> how
> to fix this without removing the head (or even if the head comes
> off.....what do you do?)
>
> Sudgestions so far include "Burn it out" though i dont know how, "Stronger
> Drill Bits" which are on order but have low expectations, and "replace the
> head".
>
> Any ideas are greatly appreciated!!!!!!
>
> -Craig
> '85GL (which isnt having its best day)
| 
