lawsy wrote:

I will double check the sizes of everything when I get home and post if it is different.

On another note my ballscrew has arrived from China and I'm machining the end to suit the coupling this afternoon.

I know this is an old post but any updates on it?
I also think about using ballscrew for x and y and would love some feedback if you did it.
thanks

I ordered a ballscrew from aliexpress, excellent quality (for my use at least) and all my problems with the z-axis went away. Also a lot faster to move the z axis now. Recommended

http://www.soliforum.com/topic/10012/sd … installed/

I will double check the sizes of everything when I get home and post if it is different.

On another note my ballscrew has arrived from China and I'm machining the end to suit the coupling this afternoon.

I know this is an old post but any updates on it?
I also think about using ballscrew for x and y and would love some feedback if you did it.
thanks

This math threw me off I had to pull out excel, lol

Yeah, I did the math right but typed it wrong.

[200 steps/rev]*[16]/[.8mm/rev]=4000 steps/mm.

Dimensional analysis.

The X and Y are driven by the same 6MM bore pulley and a pitch diameter 11.5mm (outside path)

So 3200 steps in the servo

Pi*D = distance of pulley
11.5*3.14 = 36.36mm

3200 steps / 36.36 = 88steps/mm

lawsy wrote:

Not sure what you mean. Original steps was 2268, new rod 4501.

The exact amount will change depending the pitch of the thread.

200steps/rev times 16 microsteps/step times 0.8mm/rev (assumes M5-0.8 thread) yields 4000 steps/rev, not 4501

This math threw me off I had to pull out excel, lol

1: the steps per rev is simple
200*16 = 3200 steps/rev  (not in my case I have 1/32 steppers so I get double

Then this is fun math I made the 4501 mistake and got the same results right and wrong way
Lets get to the default 2268 steps per mm in marlin.

Your above math is confusing because you say times .8mm/rev. Because 3200 * .8 = 2560 steps ok. I was like wait that is only marginally better then the 5/16-18 so I backed into that

First _ did 18threadspi / 25.4 convert to mm = .708

ok so the stock sd is .708 so what is 3200 * .708 = 2267.7!!!! wow ok
So same math applied to .8 step = 2560 is this right? No right but what gives?

So what if I divided the 3200 by the pitch (thinking i had inverted wrong somewhere)
3200/.707 = 4515!!! ok so maybe that was mistake above. Still wrong right

SO I converted the 18threads per inch wrong! OK so what, here is the twist.
1/18 then = 0.055 inches per thread then convert to MM

0.055 x 25.4 = 1.411 pitch for the stock rod

so lets go back to stock conversion:

3200 / 1.411 = 2267.7

3200 * .708  = 2267.7!!!

both give exact same numbers even though .708 is wrong. Since if you applied this to another rod (steps x pitch you would be off)

So stock is:
3200 / 1.411 = 2267.7

And 5M-.8

3200 / .8 = 4000

But on my sure stepper I have

6400 / 1.411 = 4535

for upgrade
6400 / .8 = 8000!!!!!

I am a dork sorry for the rant

I assume it is super precise as well, how many steps will that give you?

just to find one in 5mm-5mm.. cost more

One of these as a replacement for the threaded rod. I'm very happy with the M5 replacement however, so fitting this will be a low priority.

Are there .stl files for the coupler and the bed attachment? I am eager to try this out my self!

Take the rod_mount.stl from the very first post. Print twice and you have the coupler.
Then, see my linked post for my custom bed nut holder. It is designed for 12x12x12mm custom machined nut, but there is the openscad design at my github, so you can adjust to your liking. The linked post also has instructions for custom nut machining.

On another note my ballscrew has arrived from China and I'm machining the end to suit the coupling this afternoon.