Boss 5 Limit Switches

[amishmafia00]

I have a Boss 5 that i retrofitted with a hilbilly bob and mach3, it's been running great, i've done a couple projects on it and finally decided to iron out some of the bugs.

the thing I would most like to take care of is the z axis limit switch, i've gotten the quill stuck several times after jogging up while not paying attention. i started checking things out, the z down limit switch works, but the z up doesn't If anyone has unput on this i would greatly appreciate it

Thanks

[LowryIndustries]

Your Boss z axis limit switch is probably working just fine.

I have a Bridgeport Boss 6 Rigid Ram and I believe I may know what is going on.

If I am reading your post correctly, what you have found is if you go too far down the z axis limit switch trips, halting the mill.

When you go too far up, the z axis simply "bumps" up against it's uppermost travel and doesn't trigger anything. You could "bump" up forever!

This is exactly right. Nothing wrong here. The Bridgeport Rigid Ram mechanically allows this and is designed for this exact action.

The reason this is allowed is because there does exist a z axis uppermost limit switch of sorts, but it is a reference switch and not a limit switch.

This way, when you click the "Reference All Home" button in Mach3, the x and y axis goes to zero while the z axis rises till it trips the z axis reference switch. You will notice the z axis actually rises a bit above the reference switch and lowers to just the right height. It's a wonderfully accurate way to set the z axis height, specially when it comes to tool changes in the tool table.

This is a good thing. I use this feature extensively to raise the z axis to a repeatable consistent position, then set the z axis to zero so the reference position and axis positions are all zero, then measure the tool length down from that point to the top of the material. If you set it up so that all your tools have a negative height (-2.11, -1.65, etc.) then you can program your tool table for tool changes.

It works perfectly.

(As a note, the z axis should be 1 - 2 inches below the uppermost limit when referencing home otherwise it cannot rise above the reference switch because it's already above it, and therefore the z axis cannot reference. Simply lower the z axis and try again.)

[LowryIndustries]

I forgot to mention.

I have put together an excellent resource of materials for the Bridgeport Rigid Ram Boss mills.

Goto Affordable High Quality Adjustable Night Sights. Radical new design helps acquire proper sight alignment quickly, day or night at a price anyone can afford.
scroll to the bottom of the page and click on the Bridgeport Manuals link.

[amishmafia00]

you've got it pretty much right, i haven't used the ref all home. When this happens is when i'm jogging the Z up. And yes there are two switches. neither of them will trip the e stop and when I forget how close I am it will actually jam the ballnut and won't jog back down unless I use some mechanical persuasion. This is what I need to avoid as i've been told that this can damage the ball nut. If i'm correct the original controls use the first switch to slow the z speed to keep it from hitting the second switch too fast.

Does the ref all home use the lower switch as it's home point?

The pc that runs the mill went down so i'm in the process of setting up another. Once I get it running again i'll have to try messing with the ref all home

Thank you

[LowryIndustries]

I'm glad I can help, amishmafia00.

Heaven knows others helped me and it's good to pass it along.

A couple things you mentioned will need to be examined.

First, you mentioned nothing triggers the estop. Something's wrong here. I can't say if it's the switch or the connection to Mach3, but at the very least the lower switch should estop while the upper switch should trigger Home.

I can't say from here if it's a mechanical problem (extremely unlikely) or if it's a connection to Mach3 (possible) or how Mach3 is setup (very likely).

You've got a bit of troubleshooting to do. Par for the course on this type of installation.

This is what I suggest. You need to go to my webpage on how I installed Mach3 and:

First, reexamine your Mach3 setup. Be sure it is setup as per Dareks instructions found in the file "How to convert a Bridgeport to Mach3.pdf" file. The settings and wiring are very explicitly laid out. It's important to do this correctly or you will get the exact problems you are detailing.

Second: If the above doesn't work, download the "Series II Maintenance Manual.pdf" file and examine pages 8-2 and 11-6 thru 11-8. These pages show how to check and adjust the quill switches.

Both files are found at Affordable High Quality Adjustable Night Sights. Radical new design helps acquire proper sight alignment quickly, day or night at a price anyone can afford.. Scroll to the bottom of the page and click on the Bridgeport Manuals link. The files are on this Bridgeport page.

Between the two of these steps you should be up and running!

[LowryIndustries]

Oh, I forgot to answer "Does the ref all home use the lower switch as it's home point?"

Nope, the lower switch triggers the estop. The upper switch triggers the Home.

So, when the quill goes Home, it retracts almost all the way leaving not much more than a total of 3/8" of upward movement left. That's it. So you have to setup all your cuts into the work and clearing fixtures as negative z values.

When Mach3 is setup properly, the lower quill switch will estop, while the upper switch will cause mach3 to give the message "z stop ignored" or somesuch, and cause the quill to move toward home.

This is why I believe there is most likely a mach3 setting which is incorrect rather than a mechanical problem.