Re: [CAD_CAM_EDM_DRO] Re: Ball screws for CNC plasma cutters

Well, I had to read that one thru a couiple of times....very carefully the
second time...before I reaslly understood it.

For those of you who are still lost....he's using a split nut (something
like those on a lathe used for threading) mounted inside a cylinder. The
split nut is free to rotate within the cylinder (which is rotationally
stationary). The cylinder obviously is fastened via some means to the
longitunally moved part.

I'm sutre this would work well....provided you have the room to mount it
that way. I'll have to go with the spring mounted between two captive
nuts...which does the same job, allows for wear, is EASILY replaced by
standard ball screws when the lead screw is changed, it need no adjustment
and takes up less space.

Smoke

>Hey Smoke,
>there is a much better way to get rid of back lash.
>What you propose always will have the back lash as soon you force the nut.
>I apply frequently the self adjusting system my italian lathe has. (Last

time adjusted 4 years ago:

>back lash in the beginning 0,01mm, now 0,04mm on radius)
>Ok: where you screw normally the nut to the cross way, you put an accurate

cylinder with

>slots were the screw passes through.
>The acme nut you make has to be sloppy on the screw and has to have the

groove tip narrower than normal. The out side form is

>cylindrical and has to fit perfectly in this cylinder.
>Out side of the thread from the top you make 2 or 4 threads passing

through, drill open until the height of the thread and counter

>bore the diameter of the head of the allan screws nearly to the depth of

the drilled part ( about 4 or 5 mm less). Until now you

>part the nut horizontally on the center line of the thread with a saw type

slot mill (width 2,5 to 3,5mm depending on the size of

>the scew). Don't forget a oil hole.
>The nut you assemble with springs below the allan screw heads. After

playing a little you find out what is the right spring pressure

>and all backlash that will be left is the play between the nut outside and

the capture cylinder. The nut moves smooth and will

>collapse on the worn parts of the screw.
>
>Of cause you are able to use the same system on a normal screw. And this is

not invented it is working really good.

>
>Good luck
>Sven Peter
>
>
>
>
>Smoke wrote:
>
>> I'm just wondering...I've seen plasma cutters in use. It appears to me

any

>> attempts to hold
>> REALLY CLOSE tolerances seems to be a lot of overkill. I've never seen a
>> plasma cutting torch
>> yet that will cut a really smooth edge, hence the lack of necessity for
>> holding close tolerances.
>>
>> With this though in mind, i don't see why a person couldn't use threaded

rod

>> for the lead screw?
>> Manufacturing an "antibacklash nut for this would be as simple as placing

a

>> heavy spring between
>> a couple of hex nuts which are trapped to prevent rotation.
>>
>> I've even seen commercial nuts (used on acme screws) made this way.
>>
>> Smoke
>>
>> -----Original Message-----
>> From: ozzietwo2001@... <ozzietwo2001@...>
>> To: CAD_CAM_EDM_DRO@yahoogroups.com <CAD_CAM_EDM_DRO@yahoogroups.com>
>> Date: Sunday, February 11, 2001 10:22 PM
>> Subject: [CAD_CAM_EDM_DRO] Re: MillWizard + MaxNC-10, SuperCam &
>> Millwizard...
>>
>> >Tracy,
>> >I've found the website for Techno-isel and have found mountains of
>> >interesting stuff, but it's daunting to try wading through it all.
>> >Can you give us an idea of prices; for instance your 20" table, and
>> >if you know, ball screw and nut prices.
>> >
>> >Thanks,
>> >Jerry
>> >
>> >
>> >
>> >
>> >One major "upgrade" I've
>> >> made is using 20" X & Y tables from techno-isel to give me more
>> >area
>> >> to work with. It works great but really needs stronger stepper
>> >motors
>> >
>> >
>> >
>> >Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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>[Non-text portions of this message have been removed]
>
>
>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

discussion of shop built systems, for CAD, CAM, EDM, and DRO.

>
>Addresses:
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>Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
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>bill,
>List Manager
>
>FAQ: http://www.ktmarketing.com/faq.html
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>