Beginners screws ( was ACME ( was Re: leadscrew,

The point I was trying to make here is that if a beginner wants to go
dirt cheap, garage door track and all-thread with plywood tables,
fine. the experience gained will make the better machine MUCH
better. and faster too. learning on some precise and expensive
stuff makes one naturally measure 5 times, CAD it out three times,
then drill three sets of holes to 'fix' for parts that were unseen in
the first place.

If you figure you will one day need a 1" ball screw, but for now have
a piece of 1/2 ACME you can use, then make the table and spaces for
nuts big enough to accept the 1" nuts and flanges and such.

imagine making a table that just makes it, feeling clever how you
made things tight with just barely any clearance, but.. you'd like
just a little more Z space, then upgrade your X and Y to 1" Ball
Screws and raise the bed by over an inch to accommodate....

The other part is buying twice is the other concern.
For my test, I took a 1" pillow block bearing and pressed in a Delrin
block with 1/2-13 all-thread taped hole. I spun the delrin nut to
move the table.

Cost :
$6.00 10 ft 1/2-13 all-thread
$9.00 1" pillow block
$8.00 1.5" dia Delrin
$20.00 for 2 pieces of uni-strut
$48.00 for wheels.

less than $100.00 for the one looong axis., leadscrew, nuts, track
the works.

For my learning experience spending $100.00 is well worth the
investment.

I would not care about tossing the works, but all the parts have
value for other things so are not pure scrap.

Yes, I did have to make plates and mounts and stuff, but all that was
drilled holes, no precision machining.

I think building a mini for experience is a great idea. use wood and
roller-skate wheels and stuff to get an idea what you need to do the
job. learning itself is worth the effort.

and once you do it once, you'll realize just how easy it is to make a
table. it's like Nike says "JUST DO IT"

Dave










--- In CAD_CAM_EDM_DRO@yahoogroups.com, "David A. Frantz"
<wizard@e...> wrote:

> >
> >
> >snipped alot of stuff<<<<<<<<<<<<
> >
> I have to disagree here slightly there is not a huge difference in
> pricing between ACME thredad and all thread. You end up spending

a

> greatdeal of money that you wouldn't otherwise spend if you just

upgrade

> to the ACME in the first place.
>
> Also there are design points where even the tought of designing for

the

> ultimate makes the project impractical. Yes these are often home
> projects but it isn't unheard of in an industrial situation.
>
> So the reality is that the individual has to make due with what he

can

> justify. It does not hurt though to understand that ACME screws

are

> not that much out of line.
>
> Thanks
> dave
>
> >
> >My advice stays the same. DESIGN with the ultimate in mind (ie:
> >leave the space for it), but TEST with cheap crap(cheap

allthread),

> >and INSTALL the best cost/function you can get away with.
> >
> >As a note here, I used some cheap all-thread on a table and found
> >mistakes in the table that would have prevented me from using the
> >ball screws I so desired. the $10.00 for the screw was well worth

it.

> >
> >
> >
> >
> >
> >
> >
> >
> >