ZTW spindle grounding

[daedelus]

We discussed this over on the pcb-gcode yahoo groups a while back and I have finally got around to doing it.
I don't think you can add images to the yahoo groups so ive posted here.

Anyway, I do a lot of probing for my software product which essentially means that the tool needs to be grounded.

This is my old setup:

spindle as a probe with clip around the colet

2_e3a3b0cfc162d555d1953eb1f81954c7.jpg (83.44 KiB) Viewed 20808 times

The problem with this clip is that:
1. I can and have forgotten to attach the clip meaning there is no continuity between the tool and surface and therefore the tool often breaks and embeds itself in the workpiece and puts a big hole in the surface.

2. I can and have forgotten to remove the clip after probing and before the spindle starts up. This tends to grind away at the colet as it spins at ~8000rpm, plus it makes a horrific noise.

The only part of the spindle which offers continuity to the tool is the nut at the top.

The solution then:

spindle as a probe with a spring

2_b0a40e7b161c5140ab854502d85039b9.jpg (75.6 KiB) Viewed 20808 times

Here I have used an old feeler gauge to act as a spring to contact the nut. A wire is connected to the spring which is then grounded.
So, the tool is always grounded now which eliminates my problems of forgetfulness.
I realize that this is a solution which is specific to my ZTW spindle and your spindle may be grounded anyway but it might interest you nonetheless.

[KenH]

That is a very good idea - I just might do something like that myself.... just have to insulate the feeler gauge from frame.

Ken H>

[Country_Bubba]

Ken,
You may not have to insulate it from the frame. Use a multimeter to check and see. It may have contact now, but it is un-reliable due to the possibility of an interruption because of the lube in the bearings. By adding the strap as shown, you will be increasing the reliability of the connection.

[Zig]

CB,, how did You attach the piccies to the message? What are the instructions to do so?

[Country_Bubba]

Zig,
From the FAQ, I found this:
"Can I post images?
Yes, images can be shown in your posts. If the administrator has allowed attachments, you may be able to upload the image to the board. Otherwise, you must link to an image stored on a publicly accessible web server, e.g. http://www.example.com/my-picture.gif. You cannot link to pictures stored on your own PC (unless it is a publicly accessible server) nor images stored behind authentication mechanisms, e.g. hotmail or yahoo mailboxes, password protected sites, etc. To display the image use the BBCode [img] tag."

I am still learning this board also, so give it try and see how it goes.

[daedelus]

Art and the FAQ are correct, but I used the "attachment" method.

What I did is...
When you compose a message, there is a tab marked 'upload attachment' just bellow your message. From here you can choose and add files from your hard drive.
Once the file is added, you have the option to place your image inline.

The restrictions are... attachments must be less than 256kb and a maximum of 640x480px.

[KenH]

Your guide to setting up the probe is really good - I'm sure it will be a LOT of help to lots of folks.

Keep up the GREAT work, Ken H>