My PCB Drill

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
U would like that won't ya..!

The thought crossed my mind so tonight I got the thread.
Now I need to find a suitable stepper.

Using what shortbus said is something I considered and it's a bit too long for the small size I want with this one.

So Now I am drawing the Z axis support layout so I can get me some plastic cutting again.
 

mcgyvr

Joined Oct 15, 2009
5,394
If you were worried about the drill bit being slightly bent effecting your hole sizes wait till you see what a cabinet draw slide versus a real linear slide does.
 

shortbus

Joined Sep 30, 2009
10,045
Now I need to find a suitable stepper.

Using what shortbus said is something I considered and it's a bit too long for the small size I want with this one.
For your stepper and movement, do you have an old 5 1/4" floppy disc drive? A lot of them used a "linear stepper motor" in them, like these -
http://www.anaheimautomation.com/products/stepper/stepper-linear-actuators-list.php?cID=52 It is a stepper that has a screw instead of a rotating shaft. The screw moves in or out depending on the power to the motor. Pretty accurate too, after all they were used to read the information on the disc. Using one of these, it has the screw and motor as one package.

The drawer slides can also be cut down to the length you need.
 

shortbus

Joined Sep 30, 2009
10,045
If you were worried about the drill bit being slightly bent effecting your hole sizes wait till you see what a cabinet draw slide versus a real linear slide does.
While not as exact as a real linear slide, the good ball bearing drawer slides are pretty stable. There are a lot of small DIY PCB machines out there using them. I'm pretty sure BMorse used them in his machines too. They wouldn't work for milling metal, but do for something like this.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
If you were worried about the drill bit being slightly bent effecting your hole sizes wait till you see what a cabinet draw slide versus a real linear slide does.
Thought of that. I have smooth bearings and wait & see till what this evil genius comes up with

I don't think floppy ones that powerful for this app.

They pretty dawn small. My Motor is quite powerful.

I got the thread. Now I am trying to find a solution for back slash problem when using these bolts and nuts.
 

mcgyvr

Joined Oct 15, 2009
5,394
I got the thread. Now I am trying to find a solution for back slash problem when using these bolts and nuts.
If its just regular threaded rod or similar you could just use 2 nuts with a decent spring in between them. The springs will push each nut right up against the threads and keep "backlash" very low.

Not sure if you have a program to run it all yet but I'm very happy with Linux CNC (EMC2).
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Spring idea is what I was thinking all a long,.

I was wondering that would it prevent backslash.

Now I know it would work.

Thanks Mate
 

mcgyvr

Joined Oct 15, 2009
5,394
Spring idea is what I was thinking all a long,.
I was wondering that would it prevent backslash.
Now I know it would work.
Thanks Mate
You really don't even need the spring if you are using 2 nuts and supporting each (and preloading them on the threads). But this can really only work well when your rod is "perfectly threaded". On regular threaded rod you will have differences in the moving force because of unequal preload along the travel.

The spring works nice (for this application) when you only support 1 nut and have the other preloaded into the threads by the spring.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Hey where have u been?
Have u settled down?

I was thinking of finishing ur board today and here u are. :D.

You really don't even need the spring if you are using 2 nuts and supporting each (and preloading them on the threads). But this can really only work well when your rod is "perfectly threaded". On regular threaded rod you will have differences in the moving force because of unequal preload along the travel.

The spring works nice (for this application) when you only support 1 nut and have the other preloaded into the threads by the spring.
As for the spring Idea.

I was going to put spring between two nuts and tighten them without squeezing the spring too much. And Use the Nuts as mounting support to the Motor mount.

U are saying use one Nut. Why is that ?
 

mcgyvr

Joined Oct 15, 2009
5,394
U are saying use one Nut. Why is that ?
I'm saying use 2 nuts BUT only fix/secure one. Let the other be pushed away by the spring but still floating. Like I said above fixing the 2 nuts doesn't allow for any movement at all and can bind if the thread spacing isn't exact.
Or fix the second nut in 2 directions but still allow it to move parallel to the threaded rod to allow it to move if the thread spacing isn't exact. Then the spring holds your preload consistent.
 

BillB3857

Joined Feb 28, 2009
2,570
In large screws with spring preloaded nuts, the nuts are adjusted to provide the desired preload then pinned together with a pin fixedon one nut and free to slide longitudinally on the other so they do not rotate individually, yet may vary in distance between them to make up the minor differences in the thread pitch of the screw.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
In large screws with spring preloaded nuts, the nuts are adjusted to provide the desired preload then pinned together with a pin fixedon one nut and free to slide longitudinally on the other so they do not rotate individually, yet may vary in distance between them to make up the minor differences in the thread pitch of the screw.
Double confusing.. :confused::confused::confused::confused::confused:

I am not a Good freakin' English literate.

Show me something,
 

BillB3857

Joined Feb 28, 2009
2,570
Here ya go! Only one nut will attach to your tool bracket. The pin makes them stay in alignment with each other. The spring between them keeps tension on the screw in both directions to prevent revering lost motion. In industry, the spring tension would be set to a particular value measured by how much torque it would take to turn the nut. For your application, probably not too important other than to not overload your motor.
 

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Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Hey that was exactly what I was thinking.
I can say you just stole my Idea. Cause I was thinking about it yesterday when I went to buy the bolt and trust me I have never seen that sorta picture before.

But my question was why 1 nut ?

I was thinking of attaching the whole nut job to the tool bracket.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Me gonna use this one....:D

I think this one is more than adequate for the Z axis drive Eh !

{ED}
I was thinking that this baby is a bit overkill...!

Do you guys think a smaller stepper would suffice. ?
 

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