Hardware store design CNC router #1

[Jimmy Southern]

Mike,

I agree with you and Ger. Lets figur on 3' for the y pipes. I really would like to be able to do full 24"x36". Hope thats ok with every one. Let us know if it isn't.

Thanks again
Jimmy

[mvaughn]

I'm not sure 3' for the Y pipes will be enough to get you 24" of travel plus a little extra for good measure.

Consider that just mounting the pipes in your gantry sides you will lose 1.5", assuming that at a minimum your gantry is 3/4" thick on each side and the pipes don't protrude through.

Your 36" pipes have turned in to 34.5" pipes

Then, you take Ger's suggestion of having 2 inches on each side for working around the edges of you part and allowing for lead-ins and read-outs

Your 34.5" pipes are now 30.5" pipes

Add in some gaps of 1/4" on each end for safe limits and now you have 30" pipes

This leaves you with 4 inches of space for the width of your z-axis. Seems a little narrow to me considering the sturdy engineering you guys are putting into the rest of the machine.

A few more inches would make all the difference in the world.

[mikeschn]

This thing is getting wide quick... Lets work backwards...

Let's allow 1" around for working, so we are at 26" of pipe.

Then allow 8" for the bearing shuttle, so we are at 34" of pipe.

Allow a double wide gantry wall plus an adjusting block, that's 2 1/4" on each side or 4 1/2", so we are at 38 1/2" of pipe.

That's a big footprint to get 24" of quality machining in the y direction. Is this what you want to see on the plans?

Mike...

P.S. I don't own a bench that wide!

[Jimmy Southern]

Mvaughn,

Yes I caught that after I posted and started thinking about it. I will have to depend on Mike or one of the other cad guys to figure the correct length of the pipes.

Ger,

Do you know what would be the least we could get by with on the lead in space. I don't want to go crazy on the floor space. I believe this will help the great gents in the cad dept.

Happy trails,
Jimmy

[Jimmy Southern]

Howdy,

Mike I believe you and I will both have a bench that wide soon. If we use Ger's as a model even with 22" we will be almost 38" just figuring on scratch paper. I believe the achilles heal has been found. I think though most will live with the loss of shop space for the quality of the machine we are designing. I'm already clearing out a space for mine. HAHAHA

Any Solutions, I want my cake and a fork?
Jimmy

[ger21]

You can get by with just over the tool diameter, but programming will be more difficult because you have to be real careful where you drop that tool.

You also should have some extra room if you use limit switches. You don't want to be always working right next to limit switches.

When you start worrying about 4", what's the point. Just make it bigger. It was no longer a benchtop machine as soon as you passed 24".

[ger21]

BTW, mine has a Y travel of about 32". You "could" make this all useable, but I'll probably never cut within 2" of the edges. When all is said and done, it'll be about 44" wide, plus the stepper sticking out the side.

[achiestdragon]

hmm if the design is going to be scaleable is the exact size important at this stage

ok so guess the same design could be converted to cope with metric or impeial sized materials ,

btw latest dimentions for the bed here get it to be 1136mm long 950mm wide for a 900*500mm cutting aria ( 44"L,37"W for 35"L 19"W cutting aria)

suppose it would be better to give the size in the following way
required cutting lenth + 236mm (10")
required cutting width + 450mm (18")

for the rail outside the bearing design

only reason im currently sticking to that is i have already have the rails cut
2*1100mm 2*700mm and 2*300mm ,

dave

ps , i should add that i do know that the actual cutting aria of my machine is going to be smaller than stated above ,
but untill built im not shure exactly how much ,looks like 56mm at the moment (2 bits of mdf )
but i only intend using it on 300*600mm matierial so it has not been my biggest concern anything above that is a bonus to me

[mikeschn]

I only had a few mintues today to play with the design... that rush job had to come first!

I quickly threw the gantry together, only to realize that it's a little tight inside that torsion box. I might have to open it up so we can get at that adjust screw in the center.

Do you have any thoughts on this? Oh, btw, the pipe is 39 3/4" long!

Mike...

[ger21]

While you always see everyone using 4 pipe adjustment blocks (1 @ each end of each pipe), you technically only need 1 to align the pipes parallel to each other. Fabrication skill may need to be higher, though.

[ger21]

Mike, for the torsion box to function properly, both skins need to be glued permanently. You can't have access to the inside. It's the skins that give it the strength, not so much the inside framework.

[mvaughn]

Originally Posted by ger21 Mike, for the torsion box to function properly, both skins need to be glued permanently. You can't have access to the inside. It's the skins that give it the strength, not so much the inside framework.

Well that makes it hard to get the the adjustment bolt now doesn't it.

Personally, I think that it's way too complicated with all those adjustment bolts. Like others have said and Spalm proved (Ger used a CNC) it is possible to accurately cut the recesses in the torsion box so you don't need the adjusters.