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lakeside53
03-10-2009, 01:30 PM
.. a typical compound or slide dial... Sure, I can turn a chunk of metal to exactly what I need, but how do I approach putting on the lines... I want it to look "factory".

I have a rotary table with indexing plates, so the 100 Div spacing isn't an issue. Crisp clean lines? and really nice numbers?

tony ennis
03-10-2009, 02:07 PM
Engraving the lines as a non-powered lathe operation is common. Getting the numbers to look professional is a different issue.

I believe Evan made some dials last year of paper. I wonder how they are holding up.

Thomas Staubo
03-10-2009, 02:42 PM
Here (http://www.neme-s.org/images/PDF%20Files/Making%20Graduated%20Collars1.pdf) is a good write-up on the subject. The link directs you to a .pdf file that you can download.


.

Mark Hockett
03-10-2009, 03:46 PM
Andy,
You are welcome to come over and use my 4th axis on the CNC mill. I went to Mastercam update training yesterday for the latest version and one of the things I discussed with them was using a C-hook function with the roll die feature to draw the part in a flat plane and roll it into a cylinder to engrave on an curved surface. I should have the new version of Mcam up and running by the end of the week but my mill is tied up for two weeks on a job.

I need to make some dials too so it would be a good practice project.

3t-
03-10-2009, 03:52 PM
lakeside,

here is a link to some pretty impressive work on this subject.

http://www.practicalmachinist.com/vb/showthread.php?t=150571

SGW
03-10-2009, 05:25 PM
I'd grind a sharp V tool from a piece of round rod (a piece of a broken tap might be good) with appropriate clearances, chuck it in your milling machine spindle, clamp the spindle from moving, and use it to scribe the lines by cranking the table back and forth.

Lining up the numbers to stamp them (assuming you do stamp them) may be more of a problem, actually. It would probably be well worth the time it would take to make a fixture of some kind to align the stamps properly and consistently.

Jpfalt
03-10-2009, 06:16 PM
I made a holder that goes into the spindle of a knee mill and ground a set of letter and numbeer stamps to standard length. Given that and a rotary table, you can precisely locate the stamp mark and control the depth by locking the quill and cranking the knee height to actually indent the stamp to specified depth.

motorworks
03-10-2009, 08:56 PM
"Problems worthy of attack prove their worth by hitting back."
- Piet Hein

Thomas Staubo
This quote was in my University physics book.
:)

lakeside53
03-10-2009, 09:31 PM
Wow... Thanks guys... I had to leave the computer and tear apart a surface grinder. I get back "hoping" for a reply, and I'm buried in great ideas...

lakeside53
03-10-2009, 09:47 PM
Andy,
You are welcome to come over and use my 4th axis on the CNC mill. I went to Mastercam update training yesterday for the latest version and one of the things I discussed with them was using a C-hook function with the roll die feature to draw the part in a flat plane and roll it into a cylinder to engrave on an curved surface. I should have the new version of Mcam up and running by the end of the week but my mill is tied up for two weeks on a job.

I need to make some dials too so it would be a good practice project.


Wrapping a flat plane onto a cylinder.. I love it... So.. I assume it can engrave the numbers also. Wow...

Mark Hockett
03-11-2009, 04:17 AM
Wrapping a flat plane onto a cylinder.. I love it... So.. I assume it can engrave the numbers also. Wow...

That would be the main purpose as the lines are fairly easy to make with some of the procedures others have mentioned. Although if you are going to do it on the CNC I would do the lines and numbers all at once.

macona
03-11-2009, 04:36 AM
Wrapping a flat plane onto a cylinder.. I love it... So.. I assume it can engrave the numbers also. Wow...

Thats how I did my rings.

Doc Nickel
03-11-2009, 05:07 AM
When I did a set of small dials, I made the lines as noted above, though on a mill: I had a cheap rotary table, and used a 200-tooth circular saw blade as an indexing plate. I scribed the marks using a small boring-bar like tool in the mill quill. Someone here gave me the idea on the saw.

I did have some number stamps, but they were a bit large, and I didn't want to risk mis-stamping the dial I'd put way too many hours into. So I took it to the local trophy shop, and had them use their cute little CNC engraver.

I don't think it had a rotary axis, I believe the operator indexed the wheel manually for each number. I wasn't there when it happened.

But, I got a very nice and consistent engraving, using an old-fashioned font.

I'll be making another set for another machine here shortly, I'll see if I can get photos of the engraving.

Doc.

Mcgyver
03-11-2009, 08:34 AM
Here (http://www.neme-s.org/images/PDF%20Files/Making%20Graduated%20Collars1.pdf) is a good write-up on the subject. The link directs you to a .pdf file that you can download.


.


that is a great write up - I really like how he uses the flex of the boring bar to get the gradual start to the line, especially as in the first pic. I've done it as SGW describes and it works well, but think Mike Burdick's takes it to the next level

Evan
03-11-2009, 10:07 AM
It's really easy to use the 4th axis to do engraving with Mach III. You slave the A axis to the Y axis and then disable the Y axis motor in Mach III motor setup. Takes about 15 seconds. Then you calculate the circumference of the workpiece and scale the Y axis appropriately so that the engraving in the flat fits the work in the round according to the angular distance per step of the 4th axis drive.

It's a simple conversion factor that you only need to calculate once based on the steps per unit of the 4th axis relative to the steps per unit of the Y axis. Once you have that conversion factor based on a unit circle you can immediately apply it to what ever radius you need when engraving a round object and scale the Y axis appropriately which drives the 4th axis as a slave.

lakeside53
03-11-2009, 01:30 PM
That would be the main purpose as the lines are fairly easy to make with some of the procedures others have mentioned. Although if you are going to do it on the CNC I would do the lines and numbers all at once.

heck, then we'll engrave 10ths on a 6 inch wheel! :D