Re: Reverse Engineering Parts

Jeffrey Lebowski wrote:

"John" <amdinc@xxxxxxxxxxxxxxx> wrote in message
news:466387EE.FF39BB64@xxxxxxxxxxxxxxxxxx
"F. George McDuffee" wrote:

On Sun, 03 Jun 2007 20:09:58 -0400, John <amdinc@xxxxxxxxxxxxxxx>
wrote:

Repair parts for machines seem be the ones that walk in the door. Our
shop does quite a bit of emergency parts where the factory parts are
not
available or have a month lead time. One of the big problems is
metalurgy.
==========
From conversation with local general service machine shops [SE
Kansas] it appears this is a growth segement. In many cases the
equipment is so old that the manufacturers are no longer in
business or have been sold to overseas companies.

Several people have told me that when they attempted to purchase
replacement/repair parts, they were bruskly advised to buy a new
machine. As several of these still had the WPB [war production
board] indicating 50 to 60 years of use, this is most likely a
good idea, although I understand that the boss almost went into
cardiac arrest when they got a quote.

At least in this area, many of the machines requiring repair are
so old that the material is almost always some version of cast
iron or mild steel. Some of the shops are getting quite good at
metal spraying, brazing, or welding to build up the worn out
parts and re-machining, and a few are developing the skills
required to replace castings with a weldment.

Anyone have to machine a replacement from the solid [yet]?

Gears still appear to be available [at a price] from the gear
companies such as Boston, but gear assemblies and shafts with
splines or integral gears are an increasing problem requiring
considerable head scratching and modification/adapting of stock
drive products.

Unka' George [George McDuffee]
============
Merchants have no country.
The mere spot they stand on
does not constitute so strong an attachment
as that from which they draw their gains.

Thomas Jefferson (1743-1826),
U.S. president. Letter, 17 March 1814.

George, we do all of that on occasion. Splined shafts are not a
problem if you have the machinery to cut them. A horizontal mill with a
long table does that. Who do you think made the original parts in a
machine. The good machine fairy. Machinists made them. The problem is
that the knowledge of the past is being lost. You need more than a cnc
button monkey to make some of these parts. I did a double lead screw and
nut a while ago in an emergency repair. No one in their area knew how
to make the screw and nut.... sad. My prices on parts usually are about
half of the factory new price for the same part and the delivery and
guarantee are a lot better. I stock bearing bronze and bar stock for
emergency repairs. I have a working relationship with a foundry close
by and can get just about anything cast that I would need for a repair.
There are a lot of tricks to make repairs on worn parts. Shaft repairs
are one of our specialties. If you haven't done long shafts you better
have a guy around that has.


I have need for a set of gears...metric module spurs, one is 21T the other
47 T

Both have internal spline....Kubota has discontinued.

Exploring having a gear shop do it but not havin a whole lotta luck--probly
gonna have to do myself.

Maybe I should take some pictures....

--

wire edm the inside spline... The external gear teeth can be cut on a
number of machines or wire edm ed too.



John
.

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