X carriage stiffening mod

So I have just edited this whole post now that I have pictures, it was pretty confusing with just a text description.

Problem: I feel that the M5 hardware holding the V-wheels on in the X carriage is flexing under load and contributing a fair amount to the deflection in the Z axis and X axis

Solution: I replaced the nylon lock nuts on the top V-wheels in the X-carriage with a solid internal threaded connector. It is very easy to do. I ordered four 5mm internal hex connectors (37mm wide with a 10mm outer hex size) from McMaster Carr. I then measured the distance between the bearing in the V-Wheels (33.65mm on my machine) and I used a belt sander to carefully grind down the 37mm long connecter to the 33.7 mm and bolted it in place with some blue Loctite on the threads.

For the bottom I did the same thing except the 5mm Cap screw going from the outside through the eccentric nut and then into the carriage, then washer, then spacer. The bottom setup is a little confusing at first and you will see once you try to put it all back as you now have three threaded things happening (nuts, bolts AND connector). If you place the eccentric nut on the bolt about halfway down and then make sure the should is properly seated into the hole on the X-carriage THEN drive the bolt into the connector it goes together very easily. The bolt also acts as a jam nut on the eccentric nuts making them virtually impossible to back out.

I am very happy with this mod and feel that it has cut my flex in the Z axis/X carriage by half. Super easy and very effective.


I am also going to replace all the M5 Locknuts on the machine with these new wide flange M5 locknuts I also picked up from McMaster Carr for something like 5 bucks for 100 pieces. I believe that they will reduce the deflection of the hardware on the other V-wheels and idler wheels that use locknuts.

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I 'm looking forward to trying your stiffening mod. I’m having some difficulty finding the hex coupling nuts you ordered from McMaster Carr. Do you happen to have a part number?


Larry J.

I can’t find an exact link to the product but this is a snap shot from my order history.

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Much appreciated.


-Larry J

Did you ever try this?

So far it has worked very well and reduced my chatter. I also find that the lower eccentric nuts keep in place a ton better and I have yet to need to readjust them after assembling this modification.

This looks brilliant, I’m going to give it a try next time I make a McMaster Carr order.

I want to do this, but i still havent had an excuse to order something and get this as add ons

I’m still waiting for parts from McMaster Carr. But I will let you know how it works out. Thanks again for the information.
Larry J.

This past weekend I ordered similar standoffs from Amazon http://www.amazon.com/Standoff-Stainless-Female-M5-0-8-Length/dp/B00PKM8T42/ - pretty sure these match up spec wise aside from being 40mm vs 37mm

I have two concerns about the part you ordered.

  1. I see the outer diameter in the specs is 8mm apposed to 10mm it may or may not matter but my goal was to get the thickest most rigid piece to span the two screws.

  2. The inside depth is listed as 12.7mm if that is true I don’t know there is enough room left inside the standoff once you cut it down to thread the screws in. These standoffs at this kind of length are not completely hollow they are just drilled out to a certain depth. I think there is over 10mm of screw sticking inward from the v wheel bearing. If you remove roughly 3.2 mm of material from each side to get the length correct you are down to about 9.5mm depth inside.

Just my speculation, but then again specs for hardware on places like amazon that don’t have the CAD drawings are usually not listed correctly anyway so none of this might even apply.

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