View Full Version : 10 20 451WA & 10 20 452WA Question

Thu 08 January 2009, 13:45
We're getting close to welding up the gantry and we have assembled (bolted) correctly (I think) the Near Gantry End Sub-weldment and the Far Gantry End Sub-weldment. However, drawings 10 20 451WA and 10 20 452WA have us scratching our heads just a little. Is it possible that the Right side views of these parts in both drawings are actually the Left side views placed on the right side of the Front view? If this is the case, we've got everything placed correctly and we can weld away, if not, we've got some more head scratching to do.

Thanks for your help,:)

Jeff and Erick

Thu 08 January 2009, 21:16
I think we've got it....as near as we can tell anyway...:o



Gerald D
Thu 08 January 2009, 22:48
Jeff and Erick, you spotted some errors there. ....452W's right view can only be correct if it is a section cut. (Similar on 400W). Looking from middle out. The photos from all the guys who have built those parts prove that they didn't read the drawings as well as you, but their intuition saved the day! :)

Edited to add:

Except in this unlucky case where the slot is on the wrong side:


The note on 10 20 451 W says SLOT FACES INWARD if 10 20 458 B is used. Not so serious - it is just to tidy up the motor wire going around the corner before it enters the gantry cross-tube.

Fri 09 January 2009, 08:47

This is one of the great things about this site and the process of building the machine yourself. A great many lessons to be taught (and learned for me) to a young person just starting out...

For all my life I've drawn using orthographic projection. So, I guess I thought this process of representing 3 dimensional objects was all the same. Last night we did a little research and learned that there is third-angle orthographic projection, used in the U.S., Canada and a few other areas the world, but that there is also first-angle orthographic projection used widely in Europe and many other parts of the world. So the lesson is, you are never to old to learn something new. It took me until I was 48 to learn about first-angle orthographic projection.:o Erick learned it at 16.:D

Thanks again Gerald.

This is a great design and process. We are having a blast.:)

Best wishes,

Jeff and Erick

Gerald D
Fri 09 January 2009, 09:00
I didn't realise that the Americas peferred 3rd angle projection. My drawings are supposed to be mostly 1st angle.


Fri 09 January 2009, 12:29
Man I love this site !!! I took drafting in highschool and we did third angle. Neat to learn the other processes.

I agree that the knowledge we are learning in building these machines is as good or better than what we will end up with at the end.

I think this would be a great project for a trade school to build over the course of the year. CAD, Welding, Metal Shop (Cuts and Bends), Body Shop, Electronics shop, Motion Control/Robotics, CAD/CAM rendering, Wood Shop, Structual Building could do all non welded assembly.

It is like a whole trade school built into one system and people on this site are all teaching each other.

Thanks again to everyone out there for sharing this knowledge.

(Slogan thread - Mechmate - "A wealth of knowledge" )


Fri 09 January 2009, 23:44
Most of the manufacturing industry in SA uses 1st angle. Production lines etc.
Why I don't know. :confused:
Construction and plant type of companies all use 3rd angle.
3rd angle is a lot easier to read when you work with semi skilled or inexperienced workers. The views are placed next to the views edge in the direction that you look at. A lot easier!
I prefer 3rd angle and my daily work is done this way.

Wed 11 March 2009, 16:07
about to weld gantey. just noticed i recieved 3 pieces 10-20-456 all identical therefor i can not face all slots inward an as per10-20-451. I am using one along with 10-20-457 on one side and two on the other therefor one slot has to face outward on the farside with the same two pieces. not sure if i should be consernred since have not recieved any 10-20-456 had i there would be no slots. bents were from alabama and all snaped together fine. would reccomend their work anytime

Gerald D
Thu 12 March 2009, 01:53
Al you your post is hard to read and I don't have a clear picture of your situation. . . .

10-20-456 do not have the side slot. The side slot is only on 10-20-458. You do not mention 10-20-458?

The reason for the side slot in 10-20-458 is only for cables/wires to pass through. It is not critical, you can pass the wires around the bracket instead of through the bracket.

Thu 12 March 2009, 06:24
gerald, thanks for the answer from what yousay i should be ok. to clarify i have 2 10-20-458 on one end on the other end i have 1 10-20-458 and 1 10-20-457. that means on the side with the 2 10-20-458 one slot has to face outward.

once again thanks,

David Bryant
Sun 30 May 2010, 18:08
Once I found this thread:
"I didn't realise that the Americas peferred 3rd angle projection. My drawings are supposed to be mostly 1st angle.


It made understanding the drawings a lot easier. I have built things all my life and mostly used 3rd angle projection, to the extent that I had forgotten about first angle projection.
(This note is just to get the idea back onto the list for those starting out.)

Sun 24 June 2012, 14:35
I'm about to make order for laser cut and bend parts. I stuck on note in the drawings "...this plate should be drilled after bending..."
Shall I tell my contractor to cut outer profile and after bending make second pass for holes?

Gerald D
Mon 25 June 2012, 00:50
The drilling is only for the "countersink". You can decide your own sequence, but it is much easier to make the countersinks before welding.