Engraving Brass Name Plates

Thanks guys. I got my stock of brass name plates in a while back and they all have a paper coating on the finished side. I was wondering if I would
get a better looking result if I engraving it first peel and then peel the paper or if I peel it first. I am using a spring loaded drag engraver in my mini mill to do the engraving. Figured I would mill a tight pocket in a block of wood and just drop the plates in it to do the work. Then there is no messy fidgeting around with placement.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Regardless of how many answers you get here, I would try both. Engraving it first might be better because you do not get scratches on the smooth surface. Or it might be worse because it is a pain to peel the paper off after engraving.
One experiment is worth ten theories. Please let us know what you find out.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Best bet is with a D point engraving point that is turning fast. If you are mechanically dragging take the paper off! More force in reverse.
Martin
snipped-for-privacy@krl.org wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Well, I have the same old hassles all over again.
I cut a beautiful pocket in a block of wood. Measured it. Yep. Just right. I tried to drop my first brass plate in to engrave it and discovered... they vary in height and width by up 1/16 inch. Most over sized. Sigh. Time to over cut my pocket and rig up some kind of narrow clamp for them at each edge.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I'm not sure about your nameplates but we machined damaged portions of Boeing 707 trim tabs by sticking them to a vertical milling machine table with double back tape. Of course the "tabs" were as long as the table but the idea might apply.
Or you might use a similar system as an engraving vise, movable jaws with pins which hold the work piece. Try http://www.progresstool.com/pd_grs_engraving_microblock_ball_vise_with_4_pins.cfm It should be easy to modify a conventional milling vise to add the pins.
Regards,
J.B.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

http://www.progresstool.com/pd_grs_engraving_microblock_ball_vise_with_4_pins.cfm
I just need to break down and start machining a fixture plate with screw in cams like the twist pins in a clamping miter box.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Do you have a diaphragm vacuum pump? Or a shop-air venturi pump? Mill out your pocket a bit oversize to allow for rubber, make two big holes for the vacuum, and drape a sheet of inner-tube rubber on top.
Get a decent seal and enough differential pressure built up, and It Will Not Move. Until you turn off the pump. And if they are slightly undersized the jig will compensate.
Don't raise the drawbridge, lower the river.
--<< Bruce >>--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Well, I do have a brake bleeder hand pump, but I don't think that will cut it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Nope, not gonna do it. You need a small (1/6 to 1/2 HP) diaphragm pump or carbon-vane pump rated to pull (guessing) around 20" of vacuum. An oil-ballasted high vacuum pump would be overkill.
An air-venturi pump like they sell at Harbor Fright for doing car air conditioners would work but they are massively inefficient with shop air, you need a true 5 HP compressor to run one.
The hand pump would work if you sat there squeezing the handle every few seconds, but any leakage and your workpiece is likely to pop out of the tooling halfway through the process, which is bad.
--<< Bruce >>--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bruce L. Bergman wrote:

(...)
Could one modify a small compressor to do that? Vent the exhaust to atmosphere and plumb the input through a trash trap?
http://www.instructables.com/id/convert-a-tire-inflator-type-air-compressor-into-a /
--Winston
--

Congratulations Robert Piccinini and Steven A. Burd, WalMart Publicists of the
Year!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

You could, but no matter how much effort you put into polishing a turd it isn't going to get a whole lot better...
Try something cheap/used but meant for the purpose, like... https://www.surpluscenter.com/item.asp?UID"52122500000550&item=4-1669&catname=air
Ore this one that is just the pump on a pedestal, you have to belt or direct drive it yourself -
https://www.surpluscenter.com/item.asp?UID"52122500000550&item=4-1808&catname=air
Many small diaphragm and carbon-vane compressors have a vacuum rating, but you have to dig into the makers' cut sheets to find them.
--<< Bruce >>--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bruce L. Bergman wrote:

(...)
Heh!
https://www.surpluscenter.com/item.asp?UID"52122500000550&item=4-1669&catname=air
https://www.surpluscenter.com/item.asp?UID"52122500000550&item=4-1808&catname=air
Cool. Thanks!
--Winston
--

Congratulations Robert Piccinini and Steven A. Burd, WalMart Publicists of the
Year!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Would a water aspirator work?
<http://en.wikipedia.org/wiki/Water_aspirators
Joe Gwinn
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.