RE: [CAD_CAM_EDM_DRO] Home built machine setup, perpendicularity

Dave,
The way Jon outlined is the most accurate, but it makes sets of 3 only.
It's a lot of work too...but some of us think stuff like that is fun!

There is a special case where you can make just
one though...I guess I should mention it.

That special case is when the pieces used to make the base and blade
are already known to have edges that are straight and parallel.

Here is the procedure:

1) Drill some holes in the end of the two pieces so they can be roughly
bolted together to form the "L" of a square. Go ahead and bolt them together
but only loosely. Flat ground stock would be ideal.

2)set up a stand on a surface plate with two dial indicators...one high and
one
low. Cheap $8 ones are fine. The stand does not have to be precise or
square...just
reasonably rigid.

3)place the rough bolted square on the surface plate and bring it up to
the indicators so one reads near the top of the blade and the other close to
the
base. The value of the indicators do not matter much...just the difference.
If desired they can be zeroed out to read the same thing. If needed use a
rough
square perpendicular to keep it from being tilted.

4) Now reverse the square so the indicators are reading the other edge of
the blade.

5) If the DIFFERENCE between the readings is the same the blade is perfectly
square to the base! (signs matter here) If the indicators happen to be set
to read the same thing they
will do so on either side of the blade when it is square.

6) If it isn't tap the blade slightly to adjust it until the difference is
the same
with repeated tests. Then snug the bolts and retest. That's it!

A couple other notes: Flat ground tool steel is offered in 18 and 36 inch
lengths
in a variety of alloys... any would do in a pinch but 4140 prehard would be
best
if you have it. The edges are fairly straight and parallel, but can be made
more so
by scraping them into the surface plate. I really should not say scraping
because it is too hard. Stoning is usually what I use. Starrett uses 120
grit
sandpaper on a wooden stick to bring in their #20 precision squares. A
24x36"
one lists for over $2000!!!

This should work for you if you just need to make a quickie reference 90
degrees
for a few uses.

It actually can be done even if you have no surface plate! (guess how?)

Long to describe...pictures would work better.

Les

Leslie M.Watts
L M Watts Furniture
Tiger Georgia
(706) 212-0242

Main page:
http://www.lmwatts.com
Engineering:
http://www.lmwatts.com/shop.html
Cnc surplus for sale:
http://www.lmwatts.com/forsale.html
Carved signs:
http://www.lmwatts.com/signwp.html


-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]On Behalf Of David A. Frantz
Sent: Friday, July 08, 2005 2:34 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Home built machine setup,
perpendicularity


Is there an online reference to generating squares? Much to be found
with respect to falt surfaces and scrapping, someof which I've done
years ago, but i never learned how to generate a square.

Thanks
Dave

>Tiger Georgia
>(706) 212-0242
>
>Main page:
>http://www.lmwatts.com
>Engineering:
>http://www.lmwatts.com/shop.html
>Cnc surplus for sale:
>http://www.lmwatts.com/forsale.html
>Carved signs:
>http://www.lmwatts.com/signwp.html
>
>
>-----Original Message-----
>From: CAD_CAM_EDM_DRO@yahoogroups.com
>[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]On Behalf Of Scott Riddle
>Sent: Thursday, July 07, 2005 9:59 AM
>To: CAD_CAM_EDM_DRO@yahoogroups.com
>Subject: [CAD_CAM_EDM_DRO] Home built machine setup, perpendicularity
>
>
>I am looking to put together my own home built CNC machine with
>linear rails and ball screws onto a heavy tube frame. I am trying to
>figure out how to drive the main X axis which will move a gantry
>over the table. I am contemplating using 2 ball screws(smaller ones)
>to drive each set of trucks. This way I can assure no racking
>problems and have increased machine stiffness. My main questions is
>if I go to the 2 screw system and I am using stepper motors how do I
>initially when build this machine get my X and Y axis perpendicular?
>Assuming that each X and Y rail setup is straight to start with.
>
>Basically can I measure perpendicularity on a 3' x 3' linear rail
>setup with something like indicators. I do not have access to any
>large right angle plates or things like that. I would think that
>there would be some clever way to measure this.
>
>I used to design machine tools for several years so I know all the
>basics but when we did this setup part it was all done with a laser.
>
>Thanks
>Scott
>
>
>
>
>
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>
>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
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>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.

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>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.

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Addresses:
FAQ: http://www.ktmarketing.com/faq.html
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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........
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