Router lift project

[Corruptor]

Hello everyone,
I'm building a table mounted router lift as my "intro to CNC" project. My first step is to get the motion under manual control, and then add the drive motors and necessary electronic components. My ultimate goal is a simple lift with a DRO and a keypad for numerical entry, plus a couple of hot keys for pre-defined heights.

Attached is a first draft of the project. I'm thinking of using an acme 1/2-10 x 12" to control the lift. I'm not showing the bearing blocks for the threaded rod, the table insert plate, or the rest of the table. I'm still working on the design.

My question: will an anti backlash nut (dumpster CNC) hold a running router in place, or will I need some sort of locking mechanism to keep it from losing height? I'm worried that vibration + gravity will cause the router to "slip" and lose height as I'm cutting. The anti backlash nut seems like it should hold, but this is all new to me...

I know I don't need the accuracy provided by this type of system. I'm building a router table soon, and I thought this would be a great way to set it up. I guess it's really a convenience thing (and a healthy dose of "best toys on the block" ).

Thanks,
Jay

[Oldmanandhistoy]

Originally Posted by Corruptor My question: will an anti backlash nut (dumpster CNC) hold a running router in place, or will I need some sort of locking mechanism to keep it from losing height? I'm worried that vibration + gravity will cause the router to "slip" and lose height as I'm cutting. The anti backlash nut seems like it should hold, but this is all new to me... Thanks, Jay

Hi corruptor,

As long as the stepper motor you use has enough holding torque there will be no problem holding position of the spindle.

Excellent idea and would save a lot of time.

John

[Zumba]

Under manual control, it absolutely will not hold.

[Corruptor]

Originally Posted by Zumba Under manual control, it absolutely will not hold.

Well, that's a bummer. Any ideas what I should do? I'm not locked in to any particular hardware, so there's no problem changing screw types if necessary.

[Zumba]

Don't worry. A simple solution for you to use until you get the stepper attached is to drill and tap a hole in the acme nut and use a set screw to hold the acme screw in place. Preferably one made of a soft material like brass with a plastic knob/handle (from McMaster). You don't need to tighten it down too much, just enough so that vibrations from cutting don't cause the scew to budge.

[Corruptor]

Hmm, that sounds simple enough. Thanks for the info. Now it's off to do some part shopping!

[vger]

You might get away with a fairly tight worm gear drive to the acme... may take a bunch of turns on a crank to get much movement out of the router, but wouldn't be as likely move unintentionally.

[Corruptor]

Originally Posted by vger You might get away with a fairly tight worm gear drive to the acme... may take a bunch of turns on a crank to get much movement out of the router, but wouldn't be as likely move unintentionally.

Something else I didn't think of. Thank you for the suggestion. As soon as I get my hands on a slide, I'll be able to start pinning this thing down.

Speaking of slides, If I use a "wide" rail and bearing car, can I get away with one car or will the weight of the router (and the forces applied during operation) require two cars (on the same rail)?

[lgalla]

Ar you designing an inverted pin router?I would be easier to start with a plunge router.There is a thread,one Z rail.

[Corruptor]

Yeah, it would be easier to work with a regular plunge router, but where's the fun in that?

I picked up a couple of slides last week, a stepper and driver board, no I'm just waiting on my lead screw. This is really just an intro to CNC building, leaving me with a nice router table. When I finally have the room I'll be moving on to bigger and better projects.

[aspenelm]

I am interested in how this progresses. I would like to make one as well. You would need a way to zero it (not difficult with a touch height sensor or whatever they are called), and how would you zero it with a bearing on the router bit.

One idea for holding position is a electronic brake, alot of servo motors have them and usually take 24vdc to energize. You may be able to find a brake for a stepper or one that is independent from the motor.

for the dro, I have seen people bolt on one of the chinese scales to the side and use it for feedback, but I like your idea of going to preset positions with a motorized setup.

[Corruptor]

If I've done the math right, the 60oz stepper should hold keep the lead screw (1/2-10) from turning without additional brake power.

As far as the zeroing goes, I'm thinking of a simple setup at first: and Alu.or steel straight edge, a battery, an LED, and a wire with aligator clip to the router bit.

Down the road I'd like to add true surface / zeroing functions, but I've got to wait until I can leave it hooked up to a PC. My whole problem right now is that the table will be in my carport, chained to the wall. I don't want to mess with a PC setup until I can enclose the garage or otherwise move this stuff indoors.

I thought about the DRO, but it just adds too much $$$ to this level of project, especially considering that I'll eventually replace it with a PC. THey make a nice add-on to those scales, a remote screen w/ function buttons. Together it would be around $100, effectively doubling the cost. I'm not an electronics guru either, so I think I'm stuck eyeballing it and doing more test cuts for now.