Design - Build feedback

Mostly Printed CNC - MPCNC Hardware Development
1

Hi

I’m just building my LR2 and have come across a slight problem with access to M4 nuts on the XZ Main to XZ &

XZ Side Belts bits.

I’m using M4 as specified as an option in the build lists but there is no room to get a small spanner on the Nylocs when tightening them (pics) - I have even printed one to try

[attachment file=97327] [attachment file=97328]

Across the flats of the nut is 7mm and the spanner I printed is 15mm wide at its widest (as seen in the pics)

Obviously, there’s ways around this in practice but just thought I’d give feedback for a future version.

 

Matt

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20190417_105030.jpg3096×4128 1.18 MB

2

Most of us just jam a flat screwdriver in there to lock it in place.

3

Yes! As I also did, but that wasn’t the reason for my posting the title, in part, it read 'Design… Feedback .

Most of you guys use probably using old imperial sizing - the rest of the world uses metric - I don’t know if these areas are perfectly sized for imperial nuts so this ‘problem’ didn’t present itself at I was just bringing it to the forums attention.

As an addendum to my original post the LR2 mount to 611 plate also has this ‘issue’

 

4

I’ve found the best method is to take a set of small vise grips and use it to hold the bolt at whatever 2 points you can get access too. A little clumsy, but it works.

5

A #6 nylon locknut is actually bigger than 7mm across flats, so it’s not really a matter of imperial vs metric measurements. I just used a pair of pliers, the slightly beefy needle nose ones.

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6

Most have to do it its seems whether or not we’re using either classic imperial or new fangled metric.

I think Ryan has chosen strength in the rigidity of the parts at the cost of this inconvenience.

6HWvGhM.jpg3264×2448

2 Likes
7

Pre thread the nylon in the nyloc nuts and then assembly is much easier. Sometimes they’re quite tight initially.

8

Thanks, it is a known design choice, nothing to do with metric or imperial on the LR. I use a set of needle nose.

The choice is giant parts forever so everyone can use a spanner one time during assembly or nice small parts use needle nose/flat head once and be done with it. Using printed parts has a severe disadvantage to metal in this regard. These sorts of choices have to be made a lot during the design process. rigidity has to be had with the highest of priorities.

Dang it…old thread. My bad.

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9

Or, just use regular nuts, then hit the ends with some superglue.

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10

I actually thought about switching to regular nuts and including some loctite. So many people seem to have an issue with nylocks. Who knew!?

11

I would definitely not do the locktite. Just because I would be sure it wasn’t the last time I installed them. But I guess at that point, it is my own fault.

12

Yeah, deep down I hope that would cause more issues than nylocks…but you never know.

13

The best solution is to pre-thread the nylon in the nyloc nuts. The first time a screw goes in it’s cutting its own threads… which is hard if the nut isn’t solidly locked in. Pre-threaded nyloc nuts are so much easier to install.