A laminator has plastic wheels to drive the rollers that pull the
lamination pouches through heated rollers. If somebody puts something
in that's too thick, the wheels break. I have no idea if spares are
available, but probably not on a Sunday.

I wasn't sure if epoxy would stick to the wheel but I repaired it
anyway. But I'll bet the repaired tooth breaks soon - they always do.

Since everybody will tell me that I can't make gear wheels I thought I
would see if I could. We have no indexing head or anything to make
gears with, so I cobbled up a holder using the old gear wheel which
has 21 teeth. If it had 16 teeth I could have made an indexing plate.
But how do you space 21 holes around a circle?

Here's the broken gear wheel on the left top, and after I repaired it
with epoxy resin, at bottom left.
http://i54.tinypic.com/fviuth.jpg

On the right is the piece of plastic that I turned up on the lathe,
and after I cut the teeth in it using the mill. I considered using
brass but I found this black rod that seems to be some exotic very
strong plastic.
I couldn't find any suitable cutters so the teeth are the wrong shape.
It doesn't seem to make a difference to the horrible piece of
engineering that it's going into, the one that broke in the first
place.
The gears still go around OK.

Here's the setup in the mill:
http://i51.tinypic.com/2uij18m.jpg

I discovered that the holder in the mill has to be very accurate. The
hole in the middle of the gears is 7mm and I don't have any bolts that
size and I didn't want to stop and make one. So there was too much
slop.
Now I think I need to buy an indexing wheel for next time!

In article 8ae6bdbf-4a75-44c4-aafb-f9fe7cc470e2
@r19g2000prm.googlegroups.com, says...
Now I think I need to buy an indexing wheel for next time!

I've had success sometimes making a single metal tooth and melting it
into the original nylon gear.

--
Skipweasel - never knowingly understood.

On Sun, 20 Feb 2011 12:44:17 -0800 (PST), Matty F wrote:

Here's the broken gear wheel on the left top,

Looks suspiciously like a lego technic gear apart from the round hole
in the middle rather than a technic spline.

--
Cheers
Dave.

On Feb 20, 8:44*pm, Matty F wrote:

But how do you space 21 holes around a circle?

21 factorises as 3 x 7

Many gear heads are reduction gear driven through a worm. This is
usually 60:1, as that has plenty of useful factors (2,3,4,5 etc and
their multiples)

The dividing disk on the worm shaft needs to have the necessary primes
on it (you aren't getting them any other way), so there will be a 7
ring on it (probably something that's a product of 7). If it is just
7, then you have to count 20 clicks (or 1 click less than 3 whole
turns).

If you have a milling spindle for your lathe (or for plastics, make a
Dremel mount), then you can use the changewheels to do division.

On Feb 21, 12:05 pm, Chris Wilson wrote:
Skipweasel wrote :

In article 8ae6bdbf-4a75-44c4-aafb-f9fe7cc470e2
@r19g2000prm.googlegroups.com, says...
Now I think I need to buy an indexing wheel for next time!

I've had success sometimes making a single metal tooth and melting it
into the original nylon gear.

The first thing I'd try in a case like this would be to bodge on a new
tooth then use it as a pattern, make a mould and cast a new one - white
metal or resin ... probably resin. And give that a go.

What would you use to make the mould?
40 years ago I used to make RTV moulds and cast epoxy in them. I've
not got around to getting the moulding material. There is a shop that
sells it near here.

On Sun, 20 Feb 2011 12:44:17 -0800 (PST), Matty F
wrote:

If somebody puts something
in that's too thick, the wheels break. I have no idea if spares are
available, but probably not on a Sunday.

Not relevant to the gears, but a clothes iron will laminate around and over
thicker items, given a little experimenting with time and temperature...



Thomas Prufer

On 20/02/2011 20:44, Matty F wrote:
A laminator has plastic wheels to drive the rollers that pull the
lamination pouches through heated rollers. If somebody puts something
in that's too thick, the wheels break. I have no idea if spares are
available, but probably not on a Sunday....

I would look at these people's range for a metal replacement:

http://www.ondrives.com/index.php

Colin Bignell

On Sun, 20 Feb 2011 21:02:33 +0000, Skipweasel wrote:

In article 8ae6bdbf-4a75-44c4-aafb-f9fe7cc470e2
@r19g2000prm.googlegroups.com, says...
Now I think I need to buy an indexing wheel for next time!

I've had success sometimes making a single metal tooth and melting it
into the original nylon gear.

Yes, or key them into the original gear and glue - the gear for adjusting
the height on my freebie camera tripod had around 1/3 of the plastic
teeth stripped out, so I re-made using aluminium.

On Sun, 20 Feb 2011 21:02:33 +0000, Skipweasel wrote:

In article 8ae6bdbf-4a75-44c4-aafb-f9fe7cc470e2
@r19g2000prm.googlegroups.com, says...
Now I think I need to buy an indexing wheel for next time!

I've had success sometimes making a single metal tooth and melting it
into the original nylon gear.

Yes, or key them into the original gear and glue - the gear for adjusting
the height on my freebie camera tripod had around 1/3 of the plastic
teeth stripped out, so I re-made using aluminium.

Matty F wrote in
:

On Feb 21, 12:05 pm, Chris Wilson wrote:
Skipweasel wrote
:

In article 8ae6bdbf-4a75-44c4-aafb-f9fe7cc470e2
@r19g2000prm.googlegroups.com, says...
Now I think I need to buy an indexing wheel for next time!

I've had success sometimes making a single metal tooth and melting
it into the original nylon gear.

The first thing I'd try in a case like this would be to bodge on a
new tooth then use it as a pattern, make a mould and cast a new one -
white metal or resin ... probably resin. And give that a go.

What would you use to make the mould?
40 years ago I used to make RTV moulds and cast epoxy in them. I've
not got around to getting the moulding material. There is a shop that
sells it near here.

For white metal I usually use ...

http://www.tiranti.co.uk/subdivision...tent=RTV%2D101
+Silicone+Rubber+%2D+Silicone+Rubber+%2D+Mouldmaki ng&Subcategory=51
&Subdivision=173

RTV- 01 silicone rubber

And resin I usually use ...

http://www.tiranti.co.uk/subdivision...sp?Content=T20
+Silicone+Rubber+%2D+Silicone+Rubber+%2D+Mouldmaki ng&Subcategory=51
&Subdivision=174

T20 Silicone Rubber

You can get the stuf elsewhere, no doubt cheaper but it's easy for me to
pop into their shop, no connection except as a satisfied customer etc.


--

All the best,

Chris