Using Z conduit as pipe for vacuum?

Mostly Printed CNC - MPCNC Advice
#1

I have this design in my head for a vacuum that uses one (or both) of the z conduits as a pipe. A vacuum hose would be attached to the top of the pipe by the z motor and a custom nozzle would attach to the bottom of the pipe allowing close positioning of the vacuum to the cut.

Before I run down this road and spend the time drawing it and printing it, I’m wary of Ryan’s instruction/advice to not attach anything to the z assembly above the tool mount. I am wondering if attaching the vacuum hose as described is going to cause problems as it will be supported from above.

#2

I’ve seen someone else doing that, but don’t forget, half the pipe is closed off for the nut traps.

#3

Yes if attached to the Z motor this is generally a bad idea. The Z section is like a teetertotter.

Stone-see-saw-true.jpg
Stone-see-saw-true.jpg1917×1002 65.2 KB

#4

Trying to picture this in my head…it really has to do with something pulling on the top of the Z assembly. For instance, let’s say I have the hose supported directly over the center of the bed well above the top of the Z assembly but it is attached to the top of the conduit pipe. When X/Y is moved from bed center to bed perimeter, the hose is now tugging the top of the Z assembly toward the center (albeit slightly) making the bit no longer square to the X/Y plane…and the fulcrum point has the potential to multiply the change at the bit.

Now I’m worried about my z motor control wires and my DW660 power cord doing the same thing!

#5

I have been considering the same.
I have previously successfully printed molds for silicone objects, and I thought a silicone hose adapter (top) and dust shoe might be a good idea ?



-and maybe design a smaller nut trap for better airflow.

#6

@Tom.

The motor wires and control wires aren’t going to be pulling on the top of the Z assembly near as hard as a vac hose though. I still think if you are milling out plywood, the z conduits are going to clog up. I get strings stuck in my dust shoe with a shop vac sized tube.

#7

Ok, y’all scared me off…So I threw out the conduit idea and made this! It uses the 660top1.stl and 660bot1.stl from Ryan’s standard DW660 mount on Thingiverse http://www.thingiverse.com/thing:944952 These are the parts that bolt to the standard MPCNC tool mount. I designed new 660top2 and 660bot2 brackets so they would hold the pipe and nozzle. The new parts will be called 660top2_vacpipe.stl and 660bot2_vacpipe.stl respectively.

The nozzle is from a design on Thingiverse by Csatti at http://www.thingiverse.com/thing:536091 It has been scaled to 84% from the original design so the 3/4" pvc fits tight when printed with PLA. BTW, I printed the nozzle WITHOUT any support on my MK2!!! Amazing!

The nozzle height in the photo allows for a 10.5mm depth of cut with the 1/8" shank bits that have the depth collar properly set at .800". I think I can get another 5mm with a redesign of the lower bracket, but right now I’m not motivated. The lower bracket already requires a little support when printing, and such a change will require even more…sorry Ryan!

I also removed the “Tool Free” collet collar and replaced it with a cover I designed. The collar was bulky and clunky and just got in my way. I now just use a 5/8" wrench. This was inspired by pictures and video from Barry.

I also need to design the vac hose adapter that goes on the top of the pvc pipe. I just happened to have one that fit, so I’ll revengeneer it.

I’m not quite finished. For one, the PVC is too long (same leverage problem as conduit idea). Once I decide on a vac hose I will cut it accordingly. Looking at bilge hose for that… http://www.gandermountain.com/modperl/product/details.cgi?pdesc=1-1/8-Bilge-Pump-Hose-per-foot&i=23604

When I am totally finished, I will pack all the parts together and put them in a zip file and post it here.

2017-01-24-08.45.22.jpg

2017-01-24-08.45.51.jpg
2017-01-24-08.45.51.jpg490×653 50.9 KB

#8

this looks tasty! thanks for your work I will be watching this thread.

Neil

#9

TRy and attache the hose directly to the mount, any rigid tube there is a bad Idea. Especially off the front of the cutter, it will act as a breaker bar and move the bit all over the place.

Also, I recently found out most hose not designed for vacuum…whistles very very loudly with a vacuum. I bout slightly thinner stuff for the lowrider and it whistled louder than the dewalt.

#10

Yes, with the long tube, it is easy to see the leverage issue by tugging on the top, so my plan is to attach the hose right at the upper mount. It appears, based on my ultra-scientific super precise engineering test of “tug and look,” to be less of an issue with the tube mounted to both mounts.
I have not bought any hose yet, so thanks for that tip. Home Depot has some good lengths of vac hose for a reasonable price.

#11

You actually don’t really need the nut traps. On my MPCNC I’ve just used nuts and it works fine.
A bit difficult to put them in place the first time, but once it is done you usually never have to remove them anyway.
So, without the nut traps i suppose you should be fine using the tubes.

#12

I posted final pics and a link to all the files in the hardware development section.