Mega V XL Bench Setup - Bench a bit smaller than CNC

[JonnieCache]

I'm in the process of assembling my Mega V XL. I didn't know the exterior dimensions of the unit when I ordered it via Kickstarter. Unfortunately, my work bench that I was going to use to set it on is only 41" deep. The depth of the unit is actually about 42 1/2". Will it be okay if the feet overhang an inch or so off the bench? From what I've assmbled so far, it seems like it would be okay, but I wanted to check here to see if this will be a problem.

Any assistance is appreciated!

[Bruce]

You could take a larger piece of plywood, a few inches more front and back, and screw it to the top of the workbench. And set the Mega V on the plywood.

[JonnieCache]

Oh, great idea! Thanks!

[shorthair]

Another option would be to add a 2x4 or 2x6 facing board around your table. That would get you to 44" and leave your table surface intact.

[martin]

I have the same problem, and am also doing the plywood approach -- I'm taking two 3/8" sheets and gluing them together to create a 3/4" slab, which I presently intend to *not* screw to the lower table (well, at least until I see if I can get away with that; vibration might encourage the sheet to slip on the table, in which case I have to fix it).

Mucking around with sag calculations, I think it'll only deflect by a microscopic amount (less than .001" per foot of overhang at a fairly aggressive load, and I have less than a foot of overhang). I am, however, sort of abusing the sagulator equations but eh, it'll probably work.

Note, if you ever plan to do aluminum with coolant, you might want to seal the plywood before putting the machine on top.

[hans]

A couple of thoughts on this:

1) Depending on tolerances and exactly how it's assembled, the Mega V may "sit" on the four yellow, steel uprights that connect the Y rails to the bed or it may sit on the 2 black, aluminum extrusions that connect the front uprights to the back uprights. (or some combination of the two). If it sits on the extrusions, extending the wooden table would not have any effect. Of course it could be that I've assembled mine wrong.

2) Regarding vibration, I've found the Mega V to be substantially more powerful than my Carve King, and when used with the pre-loaded firmware settings, it can produce significant shaking -- especially in moves from one routing area to another. To lessen that, I lowered the X & Y maximum rates and accelerations. ($110 & $111 from 16500 to 5000 and $120 & $121 from 1470 to 500). It calmed the Mega V significantly without noticeably slowing operations (in my non-production situation).

I hope this is helpful.

[Bruce]

I might have to try knocking that max rate down a bit too Hans, It does wip around if you are machining a larger project.

[JonnieCache]

I found a 4' x 4' x 23/32 piece of plywood at Lowe's. It's just big enough to address the size of the machine left to right. After bringing it home, I decided that I don't really want to screw it to my hardwood bench top. So, I'm going to try two ratchet straps with rubber corners to see how it works. I don't know what I was thinking above when I said it would overhang only about an inch or so. The bench is only 25 inches deep.

I'd appreciate feedback on this setup and perhaps this will help others also.

Here is what I have:

Bench: www.lowes.com/pd/Gladiator-Adjustable-72-in-W-x-41-in-H-Hardwood-Work-Bench/1000017977
Plywood: www.lowes.com/pd/15-32-in-Common-Pine-Sanded-Plywood-Application-as-4-x-4/1000068973
Straps: www.amazon.com/gp/product/B01EVCW4MY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I'm thinking I can use the straps from front to pack to secure the plywood to the bench. Then, I'll set up the Mega V on top. I have no experience with sag calculations, but to address martin's concerns, I'll attach the T-plate to the machine after it is positioned on the plywood. Hopefully, this will evenly distribute the weight so it isn't resting on any one or two of the legs. It should allow me to attach the T-plate flush with the plywood. Hopefully the plywood is not warped such that it causes problems, but even if it is, I expect that the weight of the Mega V will address that over time due to the extrusions underneath.

Hopefully, this addresses hans' mention in point #1 above. Then, the only concern will be the vibration and whether that causes any issues.