Molishing problem

I have an 8mm thick, 20mm od, 8mm id spacer that's pressed into a 20mm
id hole. I have no access to one side of the set up but full access
to the other. All material is aluminium alloy

The spacer is pressed in and I need it out. It can be destroyed in
the process but the surrounding material must be unaffected so I can
put a new one in.

I can't see anyway of pulling, tapping or levering it out. Thinking
to repeatedly drill into the spacer at 3 o'clock and 9 o'clock using a
3mm drill across the width of it. As I know it's 8mm thick I can make
sure the drill stops short of the material underneath that needs
preserving. This should mean that the top and bottom halves then
become loose and can just be levered out.

Sound sensible?

 

Not sure, suspect not.

How about tapping the 8mm ID hole and then screwing a bolt into it and
attaching a slide hammer to that to pull the spacer out.

Alternatively get a strong piece of steel, drill three holes, one takes
the bolt going into the tapped hole and the other two go through the
plate with nuts underneath it. Have these two rest on some part of the
casting (pack them out with something) and wind them through, bit by bit
pulling the plate (and hence the bolt screwed into the spacer).

 

That would involve buying a tapping kit and a slide hammer.

Not that I need an excuse to buy tools.

That may be molishable with stuff in the workshop. I'll have a look.

 

If you feel lucky. I'd either use a dremel and cut across it in the
positions you've suggested then collapse it and pick out the pieces or
try tapping it and using a slide hammer as suggested by Steve. If you
need taps email me your home address and I'll post a set when I get
home next weekend along with a piece of stud bar to screw into it.
Your 3rd choice is to drill it out to 10mm (or somewhere near) tap it
M12 them screw a 12mm bolt in and jack the spacer out.

 

Padsaw - which is basically a half hacksaw blade in a handle. Cut slots
in it at 3pm and 9pm, but the time of day you do it is entirely up to
you.

 

Ben escribió:

Many years ago, I'd have used an arc welder for this.

 

That would be my suggestion, but it depends on not needing to preserve
the hole that continues in at 8mm (as it will need to be partially
tapped in order to get the spacer fully tapped).

 

It'd be ok, but I'd rather not if I can help it.

 

That's pretty much what I had in mind with the drill.

Thanks for the offer, will let you know. I'm delaying the job until
I've sourced the replacement spacer anyway.

 

An M6 RawlBolt might do the job. But if it's not some freaky hardened
alloy, I'd fit a suitably worn (i.e. 7.9mm) cutting disc on the dremel,
stick it a couple of mm down the hole, cut a groove out all the way
round, knock the top out with a chisel, rinse & repeat. Shouldn't take
more than a few minutes if it isn't hardened.

 

What about the bottom of the well that the spacer sits in? If that
could stand a couple of shallow holes you could drill and tap your
spacer at 3 and 9 o'clock and then use Steve's method with a four-hole
piece of steel.

 

Waiting 6 hours between cuts is a bit extreme


--
Lozzo
Versys 650 Inter-Continental Hyperbolistic Missile , CBR600F-W racebike
in the making, TS250C, RD400F (somewhere)
BMW E46 318iSE (it's a car, not one of those 2-wheeled pieces of shite
they churn out)

 

That sounds like a reasonable plan of attack as well.

 

Nope, the material of the well can't be damaged at all. It'll weaken
it.