Can anyone help me to ream a bush near Manchester?

[gasket999]

Hi folks,

I was wondering if anyone in or around Manchester could help me to sort a small problem with an undersized bush?

I had an overdrive unit rebuilt for my old Land Rover, it looks great and is ready to fit. However... when I come to mate it to the gearbox I've found that one of the bushes used is fractionally undersized and will not fit over the corresponding shaft.

It is a well known problem with the current supplier of this particular bush and I have been told to have the bush on the overdrive unit reamed out to about 1-2 thou greater than the size of the shaft, I think the term is "blind reaming" as it would have to be done with the bush in situ - located at the base of a female gearshaft.

The bush looks like this:

... it is a metal bush with a yellow plastic mesh liner.

The overdrive unit is only small -about the size of the shoebox and you can see the bush in the picture below - it is the yellow thing at the back.

I don't have the tools or the skills to do this but am sure that someone here could help - I will of course be happy to supply beer-tokens in exchange for an hour or two's help.

Essentially I would need to drive to your premises - spend about 30 mins removing an access cover at the back of the gearbox - exposing the corresponding shaft so that we could accurately measure it with a micrometer before reaming the bush to match.

I've approached a few engineering companies locally but they don't really want to bother with such a small job.

If anyone can help or if they could recommend a suitable engineering firm within a few miles of Manchester City Centre, could you let me know?

Really appreciate your help.

 

[MattF]

It's somewhat hard, (not a pun ), trying to resist the obvious answer to the thread title.

Have you tried making a little flapwheel with a piece of dowel slotted to accept a length of emery or suchlike and just lapping/linishing it? Plonk that in a drill on slow and it'll regulate itself on the surface. Probably going to be your easiest option, and you can keep taking off a gnat's until it's spot on. You'll obviously just need to make absolutely certain that you clear any dust out of there once you've done.

 

[gordon stephenson]

As above, Or is the shaft size such that a standard fixed reamer will clean out a smidgin from the bush bore, It's probably only closed a little due to being an interferance fit when pressed into the housing.

 

[stormin]

Any idea of the size of the shaft? I have a few David Brown type adjustable reamers which may do the job provided within the size range. It's a while since I had a series gearbox in bits but I'm thinking about 3/4 to 1" diameter.

 

[Pete.]

You could scrape that bush in minutes, the material is soft. Make a hand scraper by grinding all the teeth off a small half-round file.

 

[Robotstar5]

You could scrape that bush in minutes, the material is soft. Make a hand scraper by grinding all the teeth off a small half-round file.

How many folks know what scraping is let alone how to scrape these days? it's not something taught to todays apprentices.

 

[Pete.]

True but if there is a recommendation for 2 thou clearance pretty much anything would do, you could get a piece slightly-smaller steel tube and grind the end off flat with a nice sharp edge and go around it with that taking small scrapes of plastic. I find it odd that they would put a plastic liner in a bronze bush - are you sure it isn't just paint?

 

[wyn]

I'd have thought reaming a glacier bush will just wreck it.

 

[gordon stephenson]

The bush is probably ok to scrape/ream, those sort of bushes are mainly there for support and not carrying the full rotating shaft load.

 

[Paul.]

I'd have thought reaming a glacier bush will just wreck it.

The bush is probably ok to scrape/ream, those sort of bushes are mainly there for support and not carrying the full rotating shaft load.

True but if there is a recommendation for 2 thou clearance pretty much anything would do, you could get a piece slightly-smaller steel tube and grind the end off flat with a nice sharp edge and go around it with that taking small scrapes of plastic. I find it odd that they would put a plastic liner in a bronze bush - are you sure it isn't just paint?

It's somewhat hard, (not a pun ), trying to resist the obvious answer to the thread title.

Have you tried making a little flapwheel with a piece of dowel slotted to accept a length of emery or suchlike and just lapping/linishing it? Plonk that in a drill on slow and it'll regulate itself on the surface. Probably going to be your easiest option, and you can keep taking off a gnat's until it's spot on. You'll obviously just need to make absolutely certain that you clear any dust out of there once you've done.

There are various types of glacier bush, the one shown is a DX type, these are available in a finished size ready to use and have the prefix PM on the part no.

There is also a machinable version prefixed MB, these have a slightly thicker coating and are designed to be reamed to size after fitting, the inner coating is a polymer also found under the name delrin and will ream very easily, using an abrasive as suggested above will just tear up the surface, (seen it done), these type of bearings are known as pre lubricated, this term is often mistaken to mean that the bearings have lubrication built in but will actually need assembling with a lubricant which is held in the indentations in the bearing surface.

There is also another type of glacier bush type DU which is a dry fit bearing lined with a lead and ptfe mixture, I've fitted hundreds, possibly thousands of these glacier bearings over the years when building and servicing packaging machinery, and fitted properly they will last a very long time, but when fitted incorrectly I've seen them fail in a matter of hours.

 

[Lawnmowerboy]

A bore adjuster emery on a stick Will just tear up the surface . Scraping is the best way to go.

 

[wyn]

Nice bit of info Paul.........The DU type of bushes i've always seen in motorcycle forks