Newbie Qu;ery - Banging carriage setting Z

[johnm]

Folks -

Okay, I haven't yet purchased a 'bot, the Wif & I are "fixin' to"...but am using a benchtop at school. When I reset the "Z" depth after installing a new bit, I go through the routine with the zero plate - the Z carriage drops the router to the zero plate, then it bangs and pops back as it tries to JAM the router into the plate - I can see the table flexing! At the same time the display for Z shows the Z depth increasing until it limits out, then the router stops and returns to "safe", but that then puts the "0" for Z several inches above the table. Que?

I'd appreciate your remarks on this, I'll be futzing with it when I go in on Saturday, so I won't be able to call SB for any hand holding. A "checklist" of sorts would sure help, and if anyone is going to be around on Sat Morning (west coast time) that could take a pitiful phone call, or email exchange... Well, I'd like to have your chillun!

[Brady Watson]

John,
It sounds to me like either your wire for your z-zero plate is broken, poorly connected to Output 1, you have a bad ground or you are trying to zero a coated bit. Tin, diamond and other coated bits are electrically isolated from the router. To test for the 1st 3 conditions, just touch the zero plate to the router body or collet and watch for the Input 1 light to come on. If it does, then that rules out problems with ground and broken wires...If not, then check the connections at the control box as well as continuity of the wires (make sure it isn't broken or chaffed). Also make sure that your machine is grounded.

-Brady

[gerald_d]

John, do you have a crocodile clip, attached to the machine ground, that you clip to the bit before you start the zero routine? I get the impression that this clip was not supplied with earlier setups - or your's may have been pinched for a "roach clip (http://en.wikipedia.org/wiki/Roach_clip)" by your star students.

[mikejohn]

Gerald,how do you know these things?

...........Mike

[Brady Watson]

The alligator clip is only needed if your machine ground & control box ground are not connected to the same electrical ground of the router. Not sure if this opens up ground loop issues or not on the newer tools, but I have never had a problem running my PRT with the router or plasma using a common ground. Since all of the tools are powder coated...electricity will not flow through the powder coating...therefore, unless you share a common ground with your router's electrical connection, there will be no continuity. The alligator clip may need to be used as Gerald suggests, if for some reason there isn't continuity between the router body and the brushes/motor shaft.

-Brady

[hespj]

"The alligator clip is only needed if your machine ground & control box ground are not connected to the same electrical ground of the router."

If the router has a ground.

[gerald_d]

Mike, from school programmes teaching parents what to look for on their kids's tables.


Yes John. Some routers are plastic-cased, or double insulated and therefore not connected to the SB ground via the bracket. Brady, if you have "continuity between the router body and the brushes" then something is seriously wrong!

[Brady Watson]

Well let's not get caught up on technical semantics. You don't need the clip as long as you have continuity between the collet/tool and the outer case of the router. The body of the router should be grounded regardless and I believe that on most METAL cased routers there should be continuity thru the bearings. I'm not a motor expert...just trying to help a guy out.

-Brady

[paco]

Here a variation...


3678

[hespj]

Brady, you're absolutely right. Because I, and some others outside the US, have used different brands of router, none of which will have a ground, I assumed this was commonplace. On reflection I can see that in the US, when a router is used (as opposed to a spindle) it will probably (99%?) be a PC.

John

[johnm]

Folks -

I discovered that I had an open wire between the z plate and the computer - the pigtail from the z plate goes into a little two wire connector (white & black) with a couple of tiny wires coming out. I stripped and reconnected the wire as it had pulled out of the socket, having caught on the router carriage.

It all works great now, like green through a goose. I don't know what the little plug is for or what the white lead connects to? There isn't any other terminal or mating plug within plug-in distance. Any ideas?

John

[richards]

John,
The little plug is just a connector to connect the plate, alligator clip and cable together. Inside the control box, the white lead goes to one of the inputs and the black wire goes to ground (at least inside my alpha's control box). When you touch the Z-zero plate to something that is grounded, the circuit is complete and the selected input light turns on.

[johnm]

Mike -

So the white wire is an additional input that can be used to control something, no? Sometimes my mind boggles thinking about the different applications that the tool has...

Hmnnnnn.....

John

[bill.young]

John,

That plug connector is put there to connect a probe...they come with the matching plug installed..but you can use it for anything that needs an input switch connection The white wire is shared between that plug and the z-zero plate and connects to the input switch connection in the control box. The black wire connects to ground in the box. The ground wire isn't used by the z-zero plate because it grounds through the bit when contact is made, but some other type of switches (including the probe) need a ground connection.

Bill