Frequently Asked Questions

How do these leadnuts work?
The way that these work is that the spring pushes the sleeve away from the flange and against the angled end of the main leadnut body causing the slotted fingers to close on the lead screw, this puts even and constant pressure on the lead screw and results in a smooth - low friction movement with little to no measurable backlash and plenty of automatic wear compensation.

What kind of accuracy can I expect?
This is a loaded question. I would like to be able to guarantee less than .001 backlash, but there are too many other variables involved. On my cnc router and converted mini-lathe, I am getting less than .0005 backlash and have backlash comp turned off in Mach3. I've had many reports with the same results. There are many sources of backlash besides the lead nuts including motor endplay if direct drive and belt-pulley sloppiness if not. Leadnut mounting method is also a source of backlash as is a non-thrust bearing setup. Friction is one variable that can cause backlash with these lead nuts, I've tried these on a Sieg X2 mini-mill and with the gibs tightened, the backlash was .008-.010 due to the natural flexing of the Delrin... the tighter the gibs, the more the Delrin flexed. The high friction of the mini-mill gibs makes these a poor choice for that type of machine.
The bottom line: If the mechanics of your machine has no backlash and you have low friction linear motion, these leadnuts will give you near zero backlash.


How long will these leadnuts last?
Good question, I've never worn one out. I used a set of the 1/2-8 (2 start) for over a year before I upgraded to another size, when I removed them, they looked like the day I put them on. If you run your machine 10 hours a day - 7 days a week, obviously they will wear faster than a casual user. The design will hold the accuracy to the end, however.

Single start?, 2 start?, What the...?
A 1/2-10 (2 start) screw actually has (2) 1/2-5 threads side-by-side. They will move an axis twice as fast as a single start thread at the same rpm taking advantage of the higher torque at lower rpm of the stepper motors. Multi-start screws are also much more efficient.
NOTE: If you are using a single start screw, then you must use a single start leadnut, same with the others.


What if my nuts are too tight?
Umm... ok... They shouldn't be too tight, only snug and you should be able to turn them with a finger and thumb, you shouldn't have to grip them for them to turn. All lead screws are not created equally, if you use a different supplier than I recommend (sometimes even the same supplier!), they may fit differently. We've had good luck when I suggest to file 2 or 3 notches around the last 2-3 threads of the lead screw and force it through the back of the leadnut only under the flange area, basically working as a custom tap; it usually doesn't take much. You are welcome to try this, otherwise, you can return them and I'll see if I can open them up here.

Do these leadnuts need to be lubricated?
No, Acetal is internally lubricated, although oil/grease will not hurt them if you choose to. I've had good feedback that the finger slots in the leadnuts hold in lithium grease very well.

Are there any lead screw preparations?
The lead screw (mainly the UN threaded rod) you buy may be a little rough with burrs and may need to be sanded and polished before use with any leadnuts to reduce wear of the leadnuts. Using a lathe is recommended, if a lathe is not available, you can insert the end of the screw in a power drill to sand and polish it. Just remember, the smoother the screw is, the longer your leadnuts will last! Generally the better quality ACME screws are very smooth and need no prior polishing.

Can you make custom sizes?
In many cases, I will custom make sizes for you that I do not currently stock for similar pricing. I will then add that size to my stock. Due to design limitations, 5/8" sizes are the largest I am making for now. e-mail me with your needs. Be prepared to send me a sample piece about 6-10" long for test fitting.

Do you guarantee your work?
I take great pride in the quality of work I do. I will offer a 1 year free replacement guarantee on products that fail due to design, material, or fabrication. Simply put: If its my fault, I'll replace it. If you drop it and step on it or leave it in the toaster oven too long, I'll be glad to sell you a replacement. : )