Back to Ganoksin | FAQ | Contact

Rolling mill uneven rollers


#1

I have a Durston C130 mill, and the rollers have somehow become
uneven, ie the gap at one side between the rollers is greater than
the gap on the other side; result, wonky, “flared” sheets. I am
wondering what kind of technical expert I need to adjust it? The
firm that sold it is on mainland Australia (I’m not) and the postage
would be prohibitive for me to send it over there. Any help much
appreciated!


#2

On mine, I just lift the adjustment wheel to disengage it from the
two gears, then rotate one or both gears independently until the
rolls are parallel. Do it by one tooth at a time, roll a bit of
copper and measure it with a micrometer; it takes a while but quite
doable yourself.

Regards, Gary Wooding


#3

You could try sending an email to Matt at Durston for a suggestion.
@ durston.co.uk


#4

Anna,

What you might want to do is to first remove the rolling mill’s top
adjusting wheel. Older Cavallin mills just pull straight off, but
the Durston’s have a retaining ring just above the top rollers. This
is easy enough to remove with a round-nosed pliers.

There is a plastic cover plate on the new Durston bench mills, held
on by 4 bolts that come off with an allen wrench.

Once you’ve pulled off the adjusting wheel (or “T” bar on
Cavallins), you can easily turn the two big gears which tighten or
loosen the top roller. If you adjust each gear to pull the rollers
together evenly so they touch all the way along the rollers length,
then you are ready to re-insert the adjusting wheel and gear back
between the two gears. In this way, the rollers should be adjusted
perfectly flat once again.

The retaining ring can be put back onto the adjusting wheel shaft to
keep the wheel from coming back out of the machine again.

It’s a good idea to not keep the rollers all the way together with
pressure on them.

When not using your mill, I’d recommend oiling the rollers and
keeping the mill covered.

Jay Whaley


#5

Anna,

I’ll make certain that Jay whaley sees your post. Also Matthew
Durston is very good about answering messages such as yours. He is
usually in tucson during the Gem Show, and at Rio’s Catalog in
Motion.I believe it is a rather simple adjustment, but I will let
those who know best advise you.

Hugs,
Terrie


#6

Hi Anna,

A mysterious gremlin “adjusted” the alignment on one of our mills out
at school. (A Durston, conveniently enough.) And I was moved to take
pictures while I fixed it, and write up the “How to fix” procedure
for my website. You can find it here:

http://www.alberic.net/Toolbox_Index/TabMill/tabmill.html

Regards,
Brian.


#7

You’ll need a pair of circlip pliers to remove the retaining circlip
under the adjusting wheel on the mill. Before you pull the center
adjustment gear up to make changes take the time to mark the current
relative position of the three gears. You may then adjust the
relative position of the two gears to the center gear one tooth at a
time till your mill rolls stock relatively straight (make sure the
test pieces you roll are cut from evenly thick sheet equal in length
from side to side). I recommend you also visit the Durston rolling
mill website: this topic is covered under the “Rolling mill care and
tips page 4” here:

http://www.durston.co.uk/lan-en/online-guide-p1-en.htm

You can also access the Durston site through their banner frequently
seen on the top of Ganoksin web pages.

Another satisfied Durston owner,

Michael Edwards
Flying M Designs


#8

Hi Anna, You will aleady have recived the answer by now but just in
case:

The height adjusting handle attached to the centre gearwheel/cog
(which engages the two big cogs) can be lifted up and out of
engagement. When the centre cog is lifted or removed completely,
then each of the height adjusting cogs can be turned independently.
I presume the Durston works this way because this is how rollers
mysteriously get out of alignment…someone lifted the centre handle
while making an adjustment and managed to turn only one big cog
instead of both of them.

There are many methods to get the rollers parallel again. I set the
rollers about 0.3mm apart and view the light through the gap between
them. Lower the roller using the centre handle and watch the line of
light as it gets to zero. It should disappear equally along the whole
width.

Regards, Alastair


#9

Hi Anna, if no one else has suggested this, you can actually fix this
yourself. If you befriend a mechanic, he may lend you a small
measuring tool which they use (SHIM?) to adjust the engine, it is
paper thin pieces of metal moving up in scale to several mm, and you
just slide the measure along the roller from one side to the other,
leaving the left alone and adjusting only the right hand, this way
will ensure your rollers end up exactly the same height. Should you
not understand my explanation, simply email me and I will ring you as
I am also in Oz and explain it. I have done this myself. Good Luck.
Kath.


#10

Thanks Kath, great suggestion. I’ve adjusted them at the moment so
that the metal is even on both sides, at last - thank goodness. Great
to know the list is read by others in Oz too!

Cheers
Anna
www.annamwilliamsjewellery.com


#11
If you befriend a mechanic, he may lend you a small measuring tool
which they use (SHIM?) to adjust the engine, it is paper thin
pieces of metal moving up in scale to several mm, and you just
slide the measure along the roller from one side to the other,
leaving the left alone and adjusting only the right hand, this way
will ensure your rollers end up exactly the same height. 

From an engineering aspect, this is NOT the way. When a rolling mill
is used, the pressure required to squeeze the metal being rolled is
transferred to the bearings at each end of the rollers. After a
period of use there will, inevitably, be some wear in the bearings,
making them slightly oval instead of round.

For the bottom roller this is not a real problem because it’s own
weight ensures that it settles with the gap above the roller axle.
The top roller is a different matter. When the gap between the
rollers is measured with a feeler gauge, or piece of shim moved
across them, it doesn’t lift the top roller to make the wear gap
below the axle, which is where it is when actually rolling something.
In other words, any adjustment made without pressure being applied by
the bearings will ignore any wear that has developed.

The correct way is to take a bit of copper sheet, about 3mm wide,
and roll 20-30mm of one end at the left-hand end of the rolls, then
reverse the direction to take it out and then roll the other end at
the right-hand end. You then carefully measure the thickness at each
end and adjust the rollers accordingly.

I usually take a longish strip of copper, bend it into a long "U"
shape so that the two ends are at either end of the rollers, and
roll both ends at the same time. I then measure with a micrometer and
adjust as required.

Regards, Gary Wooding