Re: [CAD_CAM_EDM_DRO] removing backlash from rack/pinion drives wasRe: Shoptask Z-axis - quadralift?

On Thu Mar 6 06:46:41 2003 jmkasunich wrote:
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@y...>
>wrote:
>>
>> Never seen that approach. But...
>>
>> What is typically done is similar. The GEAR is split (or two
>> narrow gears are used if you prefer<G>) and these two "halves"
>> are sping loaded (rotationally) against each other.
>>
>> --- In CAD_CAM_EDM_DRO@yahoogroups.com, ccq@x wrote:
>> >
>> > It might require a wider than usual gear/rack, but what if
>> > you took a slitting saw, and slit the rack right down the
>> > middle. lock one half down as usual, and then slide the
>> > other half lengthwise, one direction or the other, until
>> > all the slop is taken out. Would this be workable, or
>> > just engender extreme wear, or sosmething?
>> >
>
>Splitting the rack will not work here - the "rack" in question
>is actually the quill of the machine! Splitting the gear is
>a possibility, however the backlash will return whenever the
>cutting force overcomes the spring force. You'd need a very
>strong preload spring.

I think I see what you mean, though the possibility of partially splitting a
rack, and sawing half of it off from the side might serve to give a slidable
rack for making the indicated adjustment. I'm sorta beginning to like the idea,
as it would take out _all_ the slop, without having to worry about spring
pressure, as the gear would be physically two-blocked by the rack in each
direction. The idea might just be the berries for a router table, and if/when
wear did occur, it could be continuously adjusted out over time, (assuming
relatively even wear), until there wasn't any worth while gear/rack left to
lock down, so to speak.

Bill

>IMHO, the right way to solve the problem is to eliminate
>the rack and pinion drive completely, and use a ballscrew.
>I've got my Z-axis ballscrew mount designed and half built,
>hope to have it done in another week or so. Tonight I start
>the "banjo" (the part that attaches the ballscrew to the
>nose of the quill).
>
>John Kasunich
>
>
>
>
>
>Addresses:
>FAQ: http://www.ktmarketing.com/faq.html
>FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
>Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
>Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
>List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@..., timg@...
>Moderator: pentam@... indigo_red@... [Moderators]
>URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
>OFF Topic POSTS: General Machining
>If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
>http://www.metalworking.com/news_servers.html
>
>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.
>
>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>bill
>List Mom
>List Owner
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>


--
----------------------------------------------------------------------------
RKBA! ***** Blessings On THee, Oh Israel! ***** 4-19!
----------------+----------+--------------------------+---------------------
An _EFFECTIVE_ | Insured | All matter is vibration. | Let he who hath no
weapon in every | by COLT; | -- Max Planck | weapon sell his
hand = Freedom | DIAL | In the beginning was the | garment and buy a
on every side! | 1911-A1. | word. -- The Bible | sword.--Jesus Christ
----------------+----------+--------------------------+---------------------

Constitutional Government is dead, LONG LIVE THE CONSTITUTION!!!!!

----------------------------------------------------------------------------