Trotec Rotary Attachment Mod for Pen Engraving

[Keith Outten]

I have been looking for a solution to attach pen blanks on my Trotec Rotary attachment for some time. I came up with this solution yesterday morning, it is not elegant but its accurate and easy.

I found two pen turning bushings that fit the shafts on my rotary attachment then went through every pen kit I have in my inventory to try and find the right size Nibs, they came from a couple of my click pen kits. As luck would have it the fit is perfect, combined with the spring action on the rotary its easy to load and unload pens to engrave.

I haven't used it yet but I hope to be able to engrave some pens tomorrow.
.

[Dan Hintz]

Nice, Keith... I'll make a set up for myself when mine comes in next week.

[Chuck Stone]

that should work just fine. It is similar to what I've been doing since I got my laser.
I did find that (since I engrave 360°, full coverage) I don't need to measure each
blank.. I have a master file for small (slims) medium (Sierras) and a Large (Jr tops)
I take an average pen blank from each size, measure the diameter and make the file
size HEIGHT at π x the diameter. Make the file length longer than you need.


When you open the file, measure your tube length and draw two vertical lines in your
file that distance apart. Label them Sierra, Comfort etc. for that tube. Put them on their
own layer. You can toggle them on and off as printable. The reason for that is that each
pen tube will sit just a little differently on your 'center' so the file could start further left
or right. With the cover open, run the file and adjust the position of those lines until you
see them hit the edges of your blank exactly. Now you know for sure where to place any
text or images in the file.. and know that you could print edge to edge if you needed to.
My pen files have a half dozen sets of lines in them for different pen kits. Makes it much
easier to get everything aligned, and a LOT fewer ruined blanks! Just call up (or pull down?)
the set of lines for the pen you're about to do.

[Keith Outten]

Chuck,

Thanks, I had to read your post a couple times before I understood your technique. I get that you are using one drawing for every type of pen, placing your construction lines for each type of pen kit on individual layers. I doubt I would have thought about setting up your way but it makes sense and saves having to deal with multiple files.

Thanks again!

[Chuck Stone]

Yep .. that's what I was trying to get out..
this English thing .. it's kinda tricky at first..

I do have a couple of files, though. I'll share tube length in a file, but
the thicknesses make a difference when engraving photos. So I'll have
a thin tube file, a medium and so on. You don't see much difference when
engraving a .550" diameter file on a .595" tube . .but you would see the
problem engraving a slimline file onto a Jr Gent top tube.

[Jeff Belany]

Why doesn't someone make a rotary like that for the Epilog? That looks like a nice machine. Using gravity and rubber rollers to turn an object has never impressed me. I know a few people (much smarter than me) have modified or made their own rotary units but what about the rest of us?

Jeff in northern Wisconsin

[Keith Outten]

Jeff,

The Trotec Rotary attachment comes with two large cones for engraving large mouth glassware types of jobs and it also has a set of gravity rollers.
To engrave pens I have been trying to come up with a set of cones, the first set I made were not perfectly concentric so the pen barrel wobbled when it turned. My second attempt was the pen turning bushings and the pen kit nib combination above. The nibs were a press fit into the bushings and the bushings were a perfect slip fit on the rotary shafts. The result is a set of smaller cones that turn perfectly and they can be removed in just a few seconds should I want to use another setup.

I had an Epilog Legend Rotary attachment that had the gravity rollers in the past. I know what you mean about how difficult it is to engrave small lightweight items.
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[Mike Null]

As i recall there is a spring loaded hold down device built in to the roller assembly on the Trotec. I doubt that it would work for pens but could be used to press larger items onto the rollers.

[Chuck Stone]

IT shouldn't be too hard to make an attachment, though. Make two discs that will
ride (gravity, I know..) on your rollers. In the center, put two cones that can hold
your pen barrels. You could even shape the discs like a pulley, so they can't ride off
of the rollers.

[Keith Outten]

I expect it would be possible to take Chuck's suggestion and use a pen mandrel between the discs. Two small Corian discs on a mandrel would have enough weight to sit on the gravity rollers reliably, the down side it that you would have to remove one disc to remove or replace a pen blank.

The reason I decided not to use the gravity rollers is because the Trotec Rotary attachment tail stock is spring loaded and I wanted to be able to take advantage of the feature. Pulling the pen blank back towards the tail stock opens the Rotary so changing pen blanks is a matter is a couple seconds and it self aligns.