Need to know the specifications for the lead screws and nuts for the crossfire pro, I’m used to metric measurements so a short explanation of what the imperial measurements mean would be very helpful
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A basic explanation of lead screw pitch and starts can be found here. https://buildyourcnc.com/leadscrews.aspx
The Pro table uses an 3/8" 8tpi 4 start lead screw on the Y and a 1/2" 10tpi 5 start lead screw on the X. You can ignore the diameter of the screw in terms of movement, because the pitch and starts are what determines how far it moves per revolution. In the simplest terms an 8tpi 4 start screw and a 10tpi 5 start screw move the same amount per revolution, because if you divide the pitch(tpi) by the number of starts you get the same number (2)
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Thank you so very much for your help, and for your time. I’m glad there is such a helpful community
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So just to reiterate to see if I’m correct, both of these lead screws move one inch every two rotations?
Also is there a reason that the x axis and the y axis have different start amounts?
That is correct. It would sometimes be referred to as a .5" pitch, since it moves .5" per revolution. If you know the steps per revolution on the stepper motors, you can calculate the number of steps to move a specified distance.
I have to assume they went with a larger diameter on the X because it has a longer travel and the thicker screw has less chance of whipping(wobbling) at high speed. The 1/2" lead screw is probably not available in an 8tpi 4 start, so the 10tpi 5 start provides the same movement per revolution or step.
Are you planning to make the table larger? That is the only reason I can think of for needing to know this information. I have contemplated making it a 4x4 by changing out the Y lead screws with longer 1/2" 10tpi 5 start screws and getting longer rails, but then I would have to make a new water table.
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That makes a lot of sense now. I am planning to extend my table a little. I am worried about the whipping and wether or not having a longer lead screw will make some issues regarding the torque of the steppers.
For me the only limiting factor is the lead screws and the torque of the stepper motors, although hopefully that won’t be a problem if I don’t make the gantry any heavier
Luckily for me my employer allows me to use the work tig welder so I could build a nice stainless water table
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Cool, keep the forum in the loop on your mods. Considered same thing. I think shipability has a role in the PRO not coming in at 48x48.
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If I’m successful I’ll be sure to share, I’m surprised I haven’t seen more do it. I’m hoping that’s not because it’s a bad idea lol
I think there are.some threads, search up top.
Hello everyone
I’m looking for a link for lead screw nuts for my pro 3/8 and 1/2. Ive done a search here on the forum and can’t find it. I remember someone posted it a while back I believe Amazon. Any help would be appreciated. I need back up parts.
This place has them listed. I have never bought anything from them. 304004 Delrin AB-nut 3/8-8, 4 st acme .5"/rev CNC router leadscrew anti backlash - IMService
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That looks like what I’m looking for. Thank you very much.
@ds690 ’ve been trying to find some lead screws which I thought were the trapezoidal screws but I looked on the Langmuir website and it says they are ACME, have I been searching for the wrong thing?
They are Acme screws. You probably need 1/2" x 10tpi - 5 start lead screws.
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