Thoughts on Stiffening mod

After doing the 5 bolts in the gap mod, I pressed firmly on the spindle in each direction. The main flexibility remaining was in the belts and the v-wheels, the flex in the modified x-axis maker-slide was minimal in comparison. When stiffening a system, it is important to always focus on the week link in the chain.

I’m interested in how this works out. Let us know if you try it.

My local Lowe’s did not have the correct thickness of aluminum so I decided to go with a steel bar.
I got one that was just a bit narrower than the v-rail and had to pick through the bin to find a nice, straight one. (many were bowed)
Because the bar was narrower than the V-rail I was able to clam both the sides as well as the top and bottom of the whole assembly, keeping sure everything lined up.
Then I used my drill press to drill the holes.
TIP: Use a brand new drill bit and some kind of cutting fluid. I had no problem drilling through the aluminum, but the bar took forever.

I have a an old Shapeoko that I did this the openrail mod. Since Inventables had a Shapeoko 2 upgrade 1/2 off for blackfriday I bought the upgrade to use the new X carriage. Do you know what spacers are required to uses the 40x40 with openrail? I was thinking that I would remove the spacer washer and buy 3mm spacers from McMaster-Carr. From research I found that the proper spacing between the two makerslides is 4.1402mm. So 4.1402mm+2mm=6.1402/2=3.0701mm. Not sure if the missing 0.071mm on each side would make a difference

Angus,

Thanks for the reply but I think something is wrong with you measurements. See the attached picture you will see the rails when using 40x40 with openrail is the same as two makerslide inverted. Thus this means that you would need a total of 4.1401mm spacing like on the original x-carve.

Based on this post it was measured in the cad drawing that the proper spacing was 0.163"=4.1402mm. I think the reason everyone is using 3/16"=4.7625 is because there is no raw stock with thickness of 4.1402mm. Can anyone confirm the official spacing between the makerslides?

Thanks for measuring. FYI I did some quick CAD measurements and you will see the true spacing should be actually 57.15mm-53.0mm=4.15mm. See image

You are correct. I had to use smaller spacer washers inside the V wheel assemblies after using 3/16" aluminum tee, due to the fact that the center of the V rails was no longer in the center of the V wheels. 0.032" fiber washers worked like a charm.

Those are some gigantic V-Wheels in that drawing.

It is to scale the outer yellow spacer washer(1mmx8mm), blue bearing (5mmx18mm), there is a center washer(1mmx8mm). Also got the cad image from openbuilds part library. The images are not in scale with each other but dimensions listed are correct.

“Everything is fixable with violence and vazeline”.

Right? :smile:

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If all you have is a hammer, then everything starts to look like a nail…

Of course, if you have a big enough hammer, that’s not necessarily a bad thing…

:sunglasses:

Hope that’s a metric mallet and not imperial rubbish!

Please, ignore my two previous posts. I did miscalculate the rail-to-rail distance. What I suggested was the same as @jzhvymetal earlier which is narrower by 4.75mm (3/16").

I will delete the above when possible (it seems there is some limitation in the forum).

However… the target 44.75mm width can be achieved by flipping the linear rails (still on a 40x40 V-Slot) so that the rails stick out (instead of hugging the body of the 40x40).

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However… the target 44.75mm width can be achieved by flipping the
linear rails (still on a 40x40 V-Slot) so that the rails stick out
(instead of hugging the body of the 40x40).

I thought about doing that but I’m not sure without supporting the V on the rail it will not deform. I’m going to try removing the 1mm spacer washer and use 3mm spacers to space out the wheels.

Either way should work.

In the flipped rail solution, it is not support I would worry about. After all, there’s a bolt every 50mm (40 bolts in total for the 500m version, 80 for the 1000mm !! ). It is something else (see below).

The way I see it, both solutions address the X axis rigidity issue, but each has a pro and a con.

flipped version (44.75mm)
pro: original spacers, less stress/potential torquing on the V wheel axes
con: free/guide-less alignment

normal version (40mm)
pro: easy guided alignment
con: extra spacers, more stress/potential torquing on the V wheel axes

@jzhvymetal

A small reinforcement you could try with the normal & spacer solution (or the flipped or the original for that matter) would be to replace the top four M5x25 screws that hold the four top V wheels with two M5x80.

This way you update from four stubs to two real axes, which eliminates any worries of micro-bending of the top V wheels.

It can be tempting to do the same for the bottom four V wheels, but this is tricky due to the eccentric nuts. You would have to cut off the head of another pair of M5x80 and add another four extra lock nuts to hold the V wheels’ internal side. Then adjusting the four eccentric nuts independently will be the challenging (but not impossible) part.

Is there a chance that the M5x80 screws would rub on the belt?

Edit: I haven’t looked at it to know… It was just a thought

No, they clear the belt by a lot. They already do.

If you take a close look, the current M5x25’s are 15mm apart… so close, like they want to kiss :smile:

An M5x80 there would provide a nice solid bridge.

Cool. Nice idea.