A mod to make z-azix more stiff and easier to adjust

My z-axis v-wheels require frequent adjustment. Perhaps the stresses are higher there. Also, the spacers used in the z-axis v-wheels seem to contribute to flex and to loosening with use. And I find the z-axis v-wheels difficult to work on, due to low clearance for tools.

This modification

  • improves spindle stiffness (z-carriage contributes the most flex after the x-axis makerslide-pair is stiffened)
  • allows separate control of v-wheel holding force, plate holding force, and cam-nut position
  • provides a spacing adjustment for the z-axis lead-screw system, to minimize binding
  • makes getting a wrench on the parts easier (frequency of cussing is much reduced now)

Parts used to modify the two fixed and two adjustable z-axis v-wheels
(4) 30mm M5 standard head steel bolt
(6) M5 nylock nut
(4) M5 standard nut
(4) 1/32x1/2" steel washer
(2) inventables eccentric nut

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Why would you want to decrease the frequency of cussing??? :smile: Nice fix, I like it!

2 Likes

Wow. Nice quick and cheap. Looks like I know my next upgrade. Thanks.

Hi @Peter_Jakab - I’ll try to answer your question here.

Here’s a shot at documenting my assembly/adjustment procedure for the modified z-axis v-wheel assemblies shown in the picture at the top of this thread.

  1. tighten the M5 bolt and first nylock nut firmly onto each z-axis v-wheel (4), this nut should never need to be adjusted again

  2. assemble the remaining nut-washer-stack and attach the v-wheel assembly’s to the spindle-plate

  3. rotate the eccentric-nuts into the open position and tighten them to just snug on the spindle plate (note: the two eccentric-nut v-wheel assemblies are on the other side, not visible in the picture)

  4. mount the spindle-plate to the z-axis maker slide; this is awkward, resting the collect on a block of wood helps

  5. with wrenches on either side of the spindle-plate, working them together, rotate the eccentric-nut to make the v-wheels squeeze the makerslide; I set them so it takes firm thumb pressure on the v-wheel to make them slip

  6. working both wrenches again, tighten the nuts to squeeze then spindle-plate firmly, while keeping the eccentric-nut in its optimal position

With the parts I selected, there was no binding in the z-axis lead screw. But if there was, the spindle-plate spacing could be adjusted by choosing a different width washer. After 10 hours of cutting since installing this mod, no readjustment has been necessary. Before, I was readjusting the z-axis v-wheels after every job.

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Hi Matt:

Thanks for your reply, I understand your process, thanks for explaining it.

One reason I was interested in your modification was that my carriage assembly was binding . This was because the spindle plate was too close to the delrin nut and was actually pushing it and putting a lot of pressure on the ACME screw. The way I fixed it was using longer screws and more washers until the delrin nut could be slid behind the spindle plate without pressure.

I think that with your assembly one could adjust the distance between the plate and the maker slide by adjusting how far the v-wheel screw is into the last 2 nuts and then tightening the last 2 nuts against each other creating the perfect spacing and without having to try different combination of washers to obtain the optimal distance between the center of the v-weel and the spindle plate.

I will try this as soon as I can find some longer M5 screws.

Thanks again for taking the time to reply.

Yep. You can actually adjust the spindle plate spacing finely, by repositioning the middle nut. Could use a nylock nut so that it would retain the spacing adjustment.

The other function of the washer is to spread the load away from the edge of the hole for the eccentric nuts. The size of the M5 nut was too close to the size of the hole for the eccentric-nuts.

Hi Matt,

I am ordering the parts needed for this mod.

For the 1/32x1/2" steel washers, is that a #10 washer or something else? I don’t have a great selection locally so I have to order things online. I been using albanycountyfasteners.com for sometime now and have had good service.

Thank you.

Yes, I used the #10 washers, from Inventables for this mod. Zinc plated steel I think.

Matt,

Thanks for the verification.

In the picture you posted, what kind of spindle are you using? And how did you mount it.

​I’m using an [GMT Air Cooled CNC Spindle 0.8 kW] spindle with a [Delta VFD-M / Inverter 0.75kW 110V]
both from UgraCNC.com.​

I’ve improved the mounting since this picture was taken. It is now mounted using the [Spindle Mounting Plate]​ ​and two [DeWalt DW660 Spindle Mount] brackets from Inventables.​ I did have to file away about 1mm of heat sink on each side of the spindle to make it fit in the brackets. Alternatively, one could file the brackets instead.

This spindle is quiet, strong, and has low runout. I also like the ability to adjust spindle speed on the fly with a knob on the drive controller.

2 Likes

MattWheeler’s mod is an outstanding improvement of the X-Carve. In fact, I think Inventables should make his method the standard method of construction. It totally solved my issues with the Z-axis and 611 spindle holder. I found I didn’t need the M5 bolts since I used the existing ones that came with the 611 spindle holder. Even though the head of the original screw is not very accessible, there’s no need any more since the bolt is locked into place with the first nylock nut. Now, the v-wheels are adjusted with two wrenches that can easily reach the two “outside” nuts. The recommended 30mm bolts were too short for the 611 spindle holder. I ended up only replacing the hardware on the side with the eccentric nuts since the original spacer from Inventables and the two nuts (1 nylock and 1 standard plus 1 washer) were almost exactly the same width (9.5mm). My 611 spindle is now free to move up and down with no wobble whatsoever…thanks!

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Oups… With the dewalt spindle and it’s mount plate… We should use 35mm bolts. i just mounted the v-wheels only to find this. No space for the last nylock nut… Sigh :(. I didn’t see that your spindle mount was slimmer.

3 Likes

Hey mate @MartinLombana,

what kind of washer are you using for this? I have the DeWalt mount plate too but can’t understand what kind of washer to use.

Thanks,
Al

A m5 washer, black oxyde from inventables. And 40mm long bolts (i couldn’t find 35mm and I confirm that 40mm regular hexagonal m5 Bolts work just fine and there is enough space for the wrenches.

You can also use a regular m5 silver washer. Inox steel if possible.

Cheers!

Nice, thank you!

So the mod is (from left to right):

35/40mm screw -> Washer -> V-Wheel -> Nilock nut -> Standard nut -> Washer -> Carriage -> Nilock nut

Is this correct?

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Correct.

BUT, in the right side of the plate,

35/40mm screw -> Washer -> V-Wheel -> Nilock nut -> Standard nut -> Washer -> Carriage -> eccentric-nut

There should be_

2x 35/40mm screw -> Washer -> V-Wheel -> Nilock nut -> Standard nut -> Washer -> Carriage -> eccentric-nut

2x 35/40mm screw -> Washer -> V-Wheel -> Nilock nut -> Standard nut -> Washer -> Carriage -> Nilock nut

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Oh got it!

I made all the mod to the ecentric nut, and now they are solid! The Z axis is my last!

Done! It perfectly work!

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Does anyone have a picture of what the eccentric nut side should look like. I’ve only seen the fixed side.