Bearing Holders and XY drive nuts about cyclone-pcb-factory

[joco-nz]

Check out this pic from my build log in google-groups forum. It shows the setup for the Y axis and the exact same principle is used for the X axis:
https://09809595539352000087.googlegroups.com/attach/8a87b7aebc1c79b6/cyclone2_06.jpg?part=0.2&view=1&vt=ANaJVrEKluamyHXqyzLjFP15KMKyN-xqA9Wmp4m-OdKFclpm91-X0ExmFOyIkD41H-iMiGQ6zYcSiVsKqCynHtijeGAWk3qd_kHigYWKyZZbSP-GSdkF1mM

[ve3sjk]

Thank you, that is what I was looking for to continue the build. I built a Fireball V90 at one point and it had a similar anti-backlash system on it. Any specs on the compression spring used.

[joco-nz]

The RepRap Prusa builds have a similar concept as well.

Anyways, because I live at the butt end of the word aka Middle Earth aka New Zealand easy access to a good selection of stuff is NOT why live here. So I had to make do with what I could find and improvise a bit.

I used a USA made Champion C-676 which I cut to be a better size (about 25mm long). Its full spec in mm is:
11.125 x 53.975 x 0.813

The "cut" end is against the nut with proper wound finished end sitting flush on the washer.

The key I believe is making sure you don't get a wire diameter greater than 1mm otherwise it gets too stiff and puts to much force on the nut. Also don't get a diameter greater than 11mm. It will want to slide over the nut. If you can get this type of spec but in a length of 20-25mm would be ideal. Maybe a spring diameter of 10mm instead of 11mm would be better. 9mm will be too tight on the threaded rod with the potential to bind up.

[ve3sjk]

Luckily here in Ontario there is a home hardware not far away that has just about every spring you could think of in stock, I think they have

A large farming customer base, I was able to find extruder springs off the shelf there.

Thanks again.

[CarlosGS]

Nice build! :)
The bearings stay in place once the X threaded rod is tightened. I
recommend placing another spring to maintain tension there.

The springs I'm using are:
Length 15mm
external diam 11mm
Wire 1mm
5 turns
So basically what James said :P

[ve3sjk]

thanks for the info going to run out today and get some springs

[joco-nz]

@CarlosGS would you be able to post a pic of this spring placement on the X axis in relation to the bearing? I "think" I know what you mean but a pics worth a thousand words. :-)

[ve3sjk]

@joco-nz here is what i did............the springs seem to be working great on the drive nut, about the same force i remember on my Fireball V90 backlash system. the one on the end i will likely shorten, I can see how pre loading the bearings this way could take care of any wobble in the lead screws. There is a washer between the spring and the bearing, can't really see it in the picture

[CarlosGS]

Yep that is exactly the way to put the springs (though maybe not so long
:P)
Thanks for the picture!!
On 5 Dec 2014 21:49, "ve3sjk" [email protected] wrote:

@joco-nz https://github.com/joco-nz here is what i did............the
springs seem to be working great on the drive nut, about the same force i
remember on my Fireball V90 backlash system. the one on the end i will
likely shorten, I can see how pre loading the bearings this way could take
care of any wobble in the lead screws. There is a washer between the spring
and the bearing, can't really see it in the picture

[image: 2014-12-05 16 43 45]
https://cloud.githubusercontent.com/assets/7632604/5323472/7290345e-7c9e-11e4-80ef-061762aabbf3.jpg

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#30 (comment)
.

[joco-nz]

Ah. Hmmm. If I use a nylock nut on the ends I might have just enough room for a 5 to 8mm spring. I cut my rods close to the published V1 spec. So not a lot of remaining overhang.

[ve3sjk]

I am wondering if this may be overkill, i believe I saw a cnc once that used the springs on the ends of the threaded rod as anti backlash, i think that is how its done on vertical milling machines as well. I cut mine two short too, but i have the x axis assembled without the spring i don't see any issues without it.

[CarlosGS]

No worries, it isn't mandatory, it will work just fine without them. Maybe
you will need to tighten the m8 nuts in the future but that's all :)
On 5 Dec 2014 22:58, "ve3sjk" [email protected] wrote:

I am wondering if this may be overkill, i believe I saw a cnc once that
used the springs on the ends of the threaded rod as anti backlash, i think
that is how its done on vertical milling machines as well. I cut mine two
short too, but i have the x axis assembled without the spring i don't see
any issues without it.

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#30 (comment)
.

[joco-nz]

I have two M8 nuts on an end. They "lock" against each other. Given the torque used to lock them together I will be amazed if they come apart. I do like the look of the spring system and if I can easily source suit suitable springs I'll give it a try.

On the Carraige nuts, are you using metal or nylon M8's? I am using metal with some Teflon dry lubricant. But I wonder if nylon nuts might not be a better option.

[CarlosGS]

Oh sorry, I forgot to reply. I did purchase some nylon nuts but it turns out that they were basically locking (they do not turn nearly as better as the steel ones). Maybe there are nylon nuts that reduce backlash though.
You should be alright with teflon grease and steel rod/nuts :-)

[joco-nz]

If you have a 3d printer you can print you own plastic nuts. A little tinkering with settings they seem to work quite well. I'm using a printed nut on the z axis as an experiment at the moment.

Sent from my iPad

On 29/12/2014, at 1:44 pm, Carlos Garcia Saura [email protected] wrote:

Oh sorry, I forgot to reply. I did purchase some nylon nuts but it turns out that they were basically locking (they do not turn nearly as better as the steel ones). Maybe there are nylon nuts that reduce backlash though.
You should be alright with teflon grease and steel rod/nuts :-)

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