Limit Switches for Old Shoptask

[Grego]

I have an old Shoptask 1720 Gold with a Flashcut CNC kit. I bought it a while back but like usual got sidetracked with other stuff until recently. It was in a state of semi-assembly when I bought it. I just fixed the stepper drive and was reinstalling the z-drive motor tonight. I know this unit doesn't have limit switches. Do you guys with CNC run without limit switches? I was pretty nervous just jogging the axes around. I'm sure I would be watching like crazy if I was running a program.

Did the CNC come with limit switches? Is there an easy way to add them? I have been collecting pictures of Shoptask machines from the web for a while and I haven't found anything where i can see what would work easily. I'm sure I could come up with something but why reinvent the wheel. I searched the forum but didnt' see anything besides a few passing comments.

Would someone mind posting some shots of your x, y and z switch setups?

Thanks.

[dgapilot]

Like you, I got my Bridgemill almost a year ago and am just getting it set up. The CNC package from Shoptask didn't come with limit switches. I was working on mine over the weekend and took some pictures. I'll download them tonight. Basicly, I'm just using one switch per axis. I used the screw holes intended for the DRO to mount some aluminum angle. Then made up brackets for the switches to be mounted on the carriage. On the cross slide, I'll have fixed ramps that will triger the switch as it gets to either end of the travel. Along the lathe bed, I'll use repositionable ramps to triger the switch. That way, I can adjust the location of the limit switch for operations with or without the chuck, or with or without the tailstock. I haven't made up the Z yet, but I think I'm only going to put a limit with the quil retracted. I'll see when I get to it

[smallblock]

I had a 17-20 before I bought the Patriot. On your machine you should have the mill-drill depth stop on the front. With CNC that becomes redundant, so it would be pretty easy to mount the limit switches on the threaded rod- one above for the down limit and one below for the up limit.

[Grego]

Anything would help, if you can upload those pictures that would help a bunch. How did you use one switch? Also what type of switches did you use?

I did look at the quill stop and it is the easiest place to add them. It's just one of those things where I design a bracket then see how someone else did it and say "why didn't I do that?"

Thanks!

[smallblock]

Sorry- no pics because I don't have CNC- my suggestion was just based on what I thought would be the logical place.

[Grego]

Smallblock: The request for pics was for dgapilot. Thanks for the suggestion.

Grego

[dgapilot]

Grego,
I'm not sure how to get the pictures here, but I posted 3 pics on the gallery with some comments. Hope this helps

http://www.cnczone.com/gallery/showp...0/ppuser/16849

David

[Grego]

Okay, now it makes sense. Thanks for the pics and the explanations! I have always thought you needed two switches one at each end, you have one switch with a ramp at each end. Might be a lot simpler. Definitely easier to wire.

[dgapilot]

Much easier to wire and less $ for switches. Glad I could help. I puzzled over it for quite some time before I came up with the idea.

I made the switch brackets from .025 4130 that I had laying around. Most anything would do. The one on the cross slide is bent to a Z shape to offset it from the saddle. The angle is also spaced out with a washer on each end so it won't drag.

The angle on the lathe bed is spaced with a couple pieces of tubing to act as spacers.

If your machine already has the tapped holes, they are 5 X 0.8 MM threads.

I hope to have mine wired this weekend, we'll seee how it works!