Re: no thrust bearing - simple design ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "andrewyslee"
<andrewlee@s...> wrote:

> Hi Bob, list,
>
> While not impossible, it is not like walking into

Walmart/RadioShack

> when one wants to purchase things like linear rails, leadscrew,

etc.

> The plans I am looking at uses drill rods for guide. No one here
> seems to know what a drill rod looks like.
>
> So, just to dip my toes in to find out what it is all about, I may
> try to make something simple with drawer slides and threaded rods
> which one can easily pick up at the hardware stores, then perhaps
> become more ambitious later. (I know there are lots

of "professionals

> here, but anyone else went down this road in their "formative"

years?)

>
> How does one attach a leadscrew/threaded rod to a thrust bearing?
> Does one just make sure that the diameters are a tight fit, or are
> there screws to tighten or something?
>
> Thanks
>

Hi Andrew,

I'm not sure of the real question.

It appears like you are in the design process.

drill rod is a good quality steel, not particularaly straight and
typically withing a few thousandths of it's listed size. I found
that some one inch stuff I bought would not fit into some pillow
block bearings.

If you plan on making a table of some sort, my advice is to design it
in CAD and then figure your loads and use the spreadsheet in the
files section (beamdeflection.xls ?)to verify the loads. then make
sure that if you want, next year you can fit heavier stuff. real
easy to do in design, real hard to do latter.

There is absolutly no reason not to use all thread for testing, but
it will not have the same life or thrust as ACME and ACME will use up
more energy than ball screws.

There are lots of us using threaded rod, many use ACME and many use
ball screws.

There are lots of machines made of wood with gears or belts forgoing
screws altogether.

Regarding thrust bearings, you can make a block with a bearing for
the axial load, and attach plates then add thrust bearings. Thurst
bearings are often very very inexpensive so if you have the ability
to use them, do so.

Dave