In the design stage CNC Torch X rails

[millman52]

Getting around to making a few drawings of design thoughts for the X axis rails for my new torch.

First thoughts are to run round rails the entire length (yet undetermined) of my table.

Here is a couple pics. Feedback please.

I will most likely have design sketches similar to this for the entire table by the time I am through. It will not be a complete set of plans but enough to keep my thoughts organised. I will also be keeping a running list of Items I have to purchase. It will not be a complete list either as I have loads of "STUFF" laying around. Leftovers form other jobs, salvaged parts etc.

[massajamesb]

I would consider having a bearing that will ride underneath the rail as well, to prevent the gantry or carriage from "skipping" or lifting.
If you made something similar to the second drawing, but had one on top, and one on bottom, that would help.

[millman52]

You think the gantry will not be heavy enough @6' wide overall to keep from rocking up off the rails? Keep in mind this is an oxy fuel table & really not planning on the rapids being lightning fast.

I do appreciate your opinion. & ideas is what I am after.

I don't think there is any way for me to hook another roller underneath the round. I might be able to put something under the main rail somewhere.

[massajamesb]

well, IMHO, it would be best to overbuild first time around, you never know, you might want to add plasma later??
When my machine was chain driven, I generally only used oxyfuel. Now I use both, and supporting the underside is a must, and the gantry and carriage together weigh about 80 pounds easily. I may also have another solution, I will PM you.

[Arie]

Very interesting conception, but I think it is rather difficult to calibrate these runners when there is a difference in the middle point of the bearings. Will you making the gantry such that this can handle this? Otherwise it may be a possibility to mount the bearings on strips which can be bolted to the carrier with oversize holes to calibrate the bearings.

[arelewis]

this design is similar to a heath shape cutter now made by esab. the support rides on bearings 30" apart and the rack and pinion are verticle so the torque won't make it jump

[MAS]

I build a flame cutter close to 30 yrs. ago with that design. Works very well.
You don't need any bearings underneath. I positioned my rack gear to serve that purpose.

[millman52]

I was looking at some items in McMastercarr a couple days ago & thought I might have happened on a good alternative for rack & pinion drive for my table. Then today I seen this on here: Plasma Table Build Log Including Free Plans Link, & Pictures by Weldtutor post #6 by trevorhinze Figured it would work good on a smaller table but I still question it on a 10-12 foot table. Opinions anyone else????


Driving home from last min. Christmas shopping last evening I had a really original brain storm for my X axis rail(s). Also today I seen this posted on here: http://www.ubcustom.com/cnc/index.php?no=3

So far it seems I'm 0 for 2 on originality. but both these ideas look very good to me.

One question I would have on the round linear rail is. Wonder how well 1045CRS would hold up for the rail????

[millman52]

Holidays are over. Hoping some of the preliminary trinkets I have purchased begin to roll in. Been waiting on a few items to get a better idea of how large overall to build my table. I am wanting to be able to easily position a 4' X 8' sheet of stock without having to squeek it in there with a shoe horn.

Hoping to actually begin the building process soon.

[PlasmaGuy]

mm52,

Glad to see you are back. My current table is 5x10 and I have roughly 5" X & Y to spare. This is way to small! To do it over again I would allow at least 10".

There is a post somewhere on this forum that suggest linear rail over the round stock.

What is your thinking on that.

Take a look at these guys. http://automation4less.com/

I have not purchased anything from them yet but their web site is nice.

Good luck,

Tom

[millman52]

Originally Posted by PlasmaGuy mm52, Glad to see you are back. My current table is 5x10 and I have roughly 5" X & Y to spare. This is way to small! To do it over again I would allow at least 10". There is a post somewhere on this forum that suggest linear rail over the round stock. What is your thinking on that. Tom

I have been working on some preliminary CAD drawings for my table. Right now, allowing several inches on each end of the gantry for mechanical hardware, run off, etc. I still should have a usable area of at least 5' on the "Y" axis. I have the table set at 10' in length, but think I am going to increase the rails to 12'. Once I have a few more things "IN HAND" for my gantry, only then will I actually begin building. I'll probably even gather up & build some of the smaller pieces first. Things like my "Z" axis movement. Determine exactly how I am going to drive the axis(s), Open end timing belt, rack & pinion, etc. All this will then tell me exactly what size the table needs to be.

I am quite sure with time "round" linear bearings would certainly wear into a piece of "mild" steel as a rail. If the linear brearing cartriges had the ball bearings inside them fixed into a helical design, as opposed to straight A "soft" rail would probably last quite some time.

I am going to use the design I have posted earlier for one of my rails. I Own a Wood-Mizer sawmil that uses that same design. I have somewhere around 2500 hrs. on it. Eventually the ball bearings will wear small flat spots down the length of the round stock. The wear is very smooth & even though which still allows only a vertical settling effect. Linear movement should still be along the same exact centerline.
In this case the THC should compensate for any wear in the vertical line of movement.

I priced a few sections of steel last week & was a bit surprised to find that 3/16" X 4" strap (to use for the consumable burning bed) is currently $35.00 for 20'. 1/4" X 4" is $30.80 so in this case more costs less. $42.00 more to be exact. for my table as now designed.

[PlasmaGuy]

Another WM owner Great!

I have a '95 LT40HDG with 1200 hours and the round stock has developed a slight worn spot but not bad. I recall hearing that Woodmizer went through quite a learning curve to find the receipt for their rod. The fixture they use to hold inplace and the weld procedure is unique too. They are very serious about the closed shop policy. I'd love to see a mill but together but I'm getting off topic! Good luck!

Tom