Halfnut gets stuck about 1/2way down feedscrew

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hazenyc
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Halfnut gets stuck about 1/2way down feedscrew

Post by hazenyc »

Any tips on how to get a half-nut from getting stuck (cylinder 'skips') about 1/2way down the feedscrew on an Edison model B? Putting slight pressure with my finger when the problem comes up does the trick, but that's not a permanent solution..

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Mormon S
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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Mormon S »

There should be a screw on the carriage that pushes down on the half nut, screwing it in should do the trick. If that doesnt work, the feed screw might be damaged.

Martin

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by NEFaurora »

"There should be a screw on the carriage that pushes down on the half nut, screwing it in should do the trick. If that doesnt work, the feed screw might be damaged. "

My thoughts exactly..

I agree with Martin..

:o)

Tony K.

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Jerry B. »

Both of the above posts are correct. But please know that the adjustment is very fine. If the carriage stops and repeats a small portion of the cylinder, the adjustment screw needs to be turned down (clockwise) so the half nut better engages the turning feed screw. If the carriage bogs down and stops the feed screw from turning there is too much pressure applied by the half nut so the adjustment screw must be turned counterclockwise. A ¼ turn is a gross adjustment. So any turn on the adjustment screw must be very little, perhaps a 1/32 or 1/16th of a turn. Small adjustments will allow you to dial in the half nut. Please let us know if this helps.

Jerry Blais

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Phono-Phan »

If the adjustment doesn't work then I would inspect the feedscrew for dirt or damage in the thread at the point where it skips. I have had luck with adjusting the half nut pressure more than needed and oiling the feedscrew then running the half nut over the area where the problem is. Sometimes the threads need a good cleaning out. Try this a few times and then re-adjust the half nut back to where it just has enough contact to play through all the way.

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by 52089 »

Phono-Phan wrote:If the adjustment doesn't work then I would inspect the feedscrew for dirt or damage in the thread at the point where it skips. I have had luck with adjusting the half nut pressure more than needed and oiling the feedscrew then running the half nut over the area where the problem is. Sometimes the threads need a good cleaning out. Try this a few times and then re-adjust the half nut back to where it just has enough contact to play through all the way.
Just to add to this, any oil you use must be lightweight, like sewing machine oil. 3-in-1 or other thicker oils will be too viscous and just gum things up.

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Chuck »

I'd like to point out here that there's a huge
difference between viscosity, and the tendency for
certain concoctions such as the aforementioned
"3-in-one" oil which does get gummy after a while.

A decent quality oil of any certain viscosity
will maintain that viscosity without gumming up,
getting sticky, and turning to a horrible goo which
impedes the workings of anything it is put on to.

I regularly for the past 40 years, have been using
with perfect success, regular 20W50 automotive
engine oil to lubricate the feedscrews on all of my
cylinder machines. These include shaving machines.

Oils of differing viscosities should be used
according to the specific job required of them.

Down in the heavy, slow running, high powered portion
of the gear train, and in the spring itself, I've used
up to 140 weight gear oil mixed with a bit of graphite
with great success. That thick gear oil stays in there.

A few drops of 90 wt gear oil on the gears themselves
help with overall lubrication in that area of the
spring motor.

Working upwards toward the higher speed portion
of the motor, various weights of oil may be used.
Straight 30 weight, 10W40, 20W50, take your pick.

Then up at the highest speed most sensitive part
of the whole mechanism, (the governor) a few drops
of sewing machine oil on the bearings and the gear
suffice very nicely.

For a noisy governor pinion, a drop or 2 of
STP oil treatment will quiet that right down for
a good long while.

Why do I post this?

It is because I have done many, many experiments
using lots of different weights of oils over the
years and have found that having on hand a wide variety
of them works best for me.

Of course, this technique is definitely not for
everybody because it makes a mess and it is advisable
to have a thick layer of folded rags or paper towels
in the bottom of your machine case to soak up the
excess as it drips down.

But if you want a machine that runs perfectly and
smoothly without any warble, and always at the proper
speed, this technique does work.

This technique also works very nicely on worn out
old clocks that have loose egg-shaped pivots.
Thick oil fills the gap. Heavy stuff down in the
slow, high power portion, lighter stuff up top
in the sensitive time-keeping area.

3-in-one oil is not even any good for a squeaky
screen door hinge....
"Sustained success depends on searching
for, and gaining, fundamental understanding"

-Bell System Credo

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Chuck
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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Chuck »

double post deleted
"Sustained success depends on searching
for, and gaining, fundamental understanding"

-Bell System Credo

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AZ*
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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by AZ* »

Chuck wrote: 3-in-one oil is not even any good for a squeaky
screen door hinge....
When I was a kid, we used 3-in-one oil on bicycle chains and roller skates (the ones with metal wheels and a skate key that provided free skinned knees and elbows :lol:). When you are 7 or 8 years old, you don't know any better. Go outside and play!
Best regards ... AZ*

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Re: Halfnut gets stuck about 1/2way down feedscrew

Post by Jerry B. »

Many helpful replies but did any help? It would be nice to know.

Jerry B.

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