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View Full Version : A question on types of tubes, and another on Depth of Field



David Somers
10-21-2013, 11:58 PM
So….I am continuing my digging to determine if I want to actually buy a laser or not. A few questions I had so far don't seem to have answers in the forum, or at least I didn't recognize them. If I missed them please feel free to say……go look more, or try this link, etc.


My first question was….what is the difference between a RECI tube and a regular tube that you see listed in the Chinese lasers. I have caught lots of conversations about them covering life span, cooling requirements, etc. But what is the difference?


The next question is about the depth of field for a lens. I understand focal length as a concept and how it applies to cameras, and also to the laser. And I understand DOF in the same way. But, in practical application though, if you have a 25mm lens, what is the useable depth of field? On average of course. For a 50mm? 100mm? If you tell me there is a .5mm depth of field, are you saying that .025mm above the prime focal point and .025mm below the focal point will be acceptable? Or are you saying .5mm above it and .5mm below it will be acceptable?


Appreciate being able to lurk and search all through your posts. Been very interesting. I have a feeling that while I might love to have an Epilog or a Trotec or a Universal that might be a bit hard to swallow for a hobbiest with future ambitions. I will probably end up with a Rabbit based on much of what I have read here. That is assuming I end up doing this at all of course. I have a feeling I may be pushing things in terms of what I would really like to do with a laser.


Will have another question later on….but I need to figure out how to frame it intelligently first! Thanks everyone!


Dave

Rich Harman
10-22-2013, 12:24 AM
Depth of field (DoF) is dependent upon beam diameter and focal length. The smaller the incoming beam diameter the greater the DoF but the larger the spot size. Conversely, the larger the incoming beam diameter, the shorter the DoF but the smaller the spot size.

The beam diameter on my 80W Reci is about the size of a pencil. I almost always use a 65mm lens and that gives me a useable range of about a couple mm (+1mm, - 1mm).

David Somers
10-22-2013, 12:37 AM
Rich,

When you say your beam from the 80W Reci is about the size of a pencil, I assume you mean the lead....not the actual wooden pencil itself?

So with your 65mm lens and the 80W Reci, you have about 3/32 of an inch total depth of field. Hmmm. Then my guess is that a 100mm/4 in lens might then have a total depth of field of 1/8", or +1/16 and -1/16. Give or take?

Dave

Rich Harman
10-22-2013, 12:41 AM
No, the whole pencil, about 8mm or so. That is before it enter the lens. I also have a beam expander that widens (and collimates) the beam to twice that, which will provide for a smaller spot size.

Your estimate for the 100mm lens sounds reasonable. So far I have not found a benefit to the 100mm lens. The 65mm lens has outperformed it with every test. I even cut 1 inch thick open cell foam with the 65mm lens with near perfectly straight sides.

David Somers
10-22-2013, 12:54 AM
Rich,

It might not be worth it, but I was thinking specifically of using a 100mm lens with a wide DOF to engrave or cut on a form that has a sloping surface. One of my other questions from this evening focuses on that type of thing. Think about trying to engrave or cut on the shoulders of a vase shape for example. Or engraving or cutting on the sloping rim of a platter. Or the surface of a globe? A broader depth of field might give you more lattitude in how you approached it. Though you would likely have to combine that with other techniques like doing the engraving in bands that are within the useable DOF of the lens, or by modifying a rotary device in some way to keep surfaces aligned with the focal plane of the lens to the best extent possible.

After reading that other post you may all want to contact my doctor and recommend he consider stronger medication for me of course. But what the heck! <grin>

Dave

Rich Harman
10-22-2013, 1:00 AM
Somewhere on the intertubes there is a video of a laser created by someone that cuts or engraved motorcycle windscreens. He made a machine that continuously moved the windscreen underneath the laser to keep the surface perpendicular to, and at the correct distance from the focal point. If you were motivated enough I am sure that you could create something similar.

Rich Harman
10-22-2013, 1:03 AM
Found it!


http://www.youtube.com/watch?v=wDaAHA5ujPM

Robert Silvers
10-22-2013, 1:36 AM
http://www.buildlog.net/cnc_laser/laser_calcs.htm

Rodne Gold
10-22-2013, 3:16 AM
Reci tube is supposedly more reliable , better beam quality and fires reliably at lower powers. Lifespan supposedly much longer than cheaper tubes , and it cost more.

DOF in terms of lasers is not as defined as in cameras , basically the beam looks like an X, the sharpest focal point is the waist , above and below it , energy density drops as the wattage is concentrated on much more of an area , the DOF of a laser is where that energy density is actually still enough to promote the reaction with the material to vaporise it.
There is a common factor , I forget the exact figure , but I think its calculated where the energy density is about 70% of the energy density at the waist - doesnt mean that you cannot still have more DOF in YOUR laser as if you have a high powered laser , even 50% of the energy density at the waist of a 200w laser could be good for processing the material whereas 50% of a 50w might not promote a reaction.

Obviously on curved material , the spot size will increase with the curve dropping or rising , and thus you would not get great results on very curved or sloping stuff.

Michael Hunter
10-22-2013, 6:39 AM
Lenses and depth of field.

Generally a 2 to 2.5" (50-63mm) "standard" lens will do 99.9% of jobs with good results.
This includes everything from fine detail on anodised aluminium to cutting 30mm thick foam.

Sometimes a 1.5" lens is recommended for very fine detail. Not having one, I cannot say how much improvement one could expect.

Very occasionally a long focal length lens (4") would be useful for engraving curved surfaces or down holes, but I have only ever missed out on one job because of not having one.


PS

I was wary about taking on a job engraving curved skateboard decks : with about 10mm between the highest and lowest points on the curve, depth-of-field theory suggested that the results would be terrible using my 2" lens.

In practice, then engravings came out really well.
With a magnifying glass you could see that the quality of engraving changed across the curve, but the end results looked terrific and the customer was very happy.

Dave Sheldrake
10-22-2013, 7:14 AM
DOF in terms of lasers is an arbitrary figure where the beam size is 1.4x the focal spot diameter in either direction up/down in the Z axis.

Online calculators all make one similar mistake, they all assume the beam is M^2 = 1 when in reality most of the beams from any Gas laser have over 50% of the wavefront at much higher TEM modes. Pure Gaussian beams are a theoretical experiment as few if any commercial lasers will generate a true, pure Gaussian beam mode.

This is a theoretical TEM00 beam

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This is a TEM01 beam

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These profiles don't consider aberrations, noise, wavefront quality/radius or a number of other factors that will effect the beam profile. Unfortunately calculated beam modes and properties rarely have little to do with real world outputs. I just measured a beam with my profiler and the two pics above are totally different to the *actual* beam even a good quality tube is producing.

In general

Shorter focal length = smaller spot = higher power density = less effective depth of field.
Longer focal length = bigger spot = lower power density = more depth of field.

Spotsize is a product of focal length, input beam diameter and wavelength.

cheers

Dave

Robert Silvers
10-22-2013, 9:25 AM
M^2 does not actually change how much depth of field there is, just how much depth of field you need for the work to look good.

Dan Hintz
10-22-2013, 9:53 AM
M^2 does not actually change how much depth of field there is, just how much depth of field you need for the work to look good.

No. M^2 changes how your dots will look/burn. A poor M^2 factor can make your dots look "fuzzy" (for lack of a better scientific term), which also means you cannot get the same power density as with a M^2 = 1 beam. Depth of field, if affected at all, is only from a 2nd-order effect.

Robert Silvers
10-22-2013, 10:09 AM
We made the same point but you said 'no' to mine.

Dan Hintz
10-22-2013, 10:37 AM
We made the same point...

Possibly... rereading it, I may not have read it the way it was intended, but there's some ambiguity I'd like to clarify.

Look at this sentence from Dave again...


DOF in terms of lasers is an arbitrary figure where the beam size is 1.4x the focal spot diameter in either direction up/down in the Z axis.
An M^2 = 1 beam will have a spot size of 'X', whereas a M^2 = 1.5 beam will have a spot size of 'Y', where 'Y' is significantly larger than 'X'. Based upon this loose definition, the lower quality M^2 = 1.5 beam will actually have a longer DoF. But this is counter to what we're after, a small dot size with a high power density. The DoF definition is based upon a perfect M^2 = 1 beam, and while arbitrary, it is not an adjustable value. Saying things like "M^2 change[s]... how much depth of field you need for the work to look good" is open to odd interpretations. I suppose the proper way to interpret it would be along the lines of "Lower M^2 values reduce the usable portion of the DoF", but there is still the major caveat that a lower M^2 beam will never reach the same quality of burn as an M^2 = 1 beam, no matter how much you reduce the useable portion of the DoF. That said, once you get beyond a certain level of quality, it's all academic unless you're looking at it through a microscope.

Dave Sheldrake
10-22-2013, 11:15 AM
But, in practical application though, if you have a 25mm lens, what is the useable depth of field?

David asked about useful DOF and as Dan pointed out useful and technical are two different things depending on a lot of variables. Online calculators don't allow for variables.

David want's to cut something 3mm thick and his chosen lens set up gives a calculated DOF of 2mm at the power density he's looking for so he buys that lens (the difference between 2 and 3mm is not worth worrying about). When it arrives the useful DOF is 1.2mm when plugged in to a tube with a multimode beam.

cheers

Dave

David Somers
10-22-2013, 11:33 AM
Rich,


Cool video of the faceplate. Not sure I am ready to go quite that far, but cool!


Robert,


Thanks for the calculator link. That is helpful.


Rodne,


Thanks for the great explanations. You also caught my question exactly. The real issue is, how much leeway do I have on a curved surface before the engraver visually suffers. What is the actual useable limit before things start to look...."schnoodly." And one of my other postings from last night basically looks at ways to handle your job when your piece will exceed those limits.


Michael,


One of the other reasons I was considering a 4in lens was one of the circumstances you mentioned. Burning a flat surface that was a distance from the lens. The bottom surface of a deep platter or broad bowl when doing inlay work for example. And of course, trying to maximise the depth of field when burning on a sloped surface.


I was very surprised to hear you say you had to use a magnifying glass to see the degradation in an engraving over a slope that dropped 10mm? That was much more flexible than I was expecting looking at the numbers from Roberts calculator link, and from talking with the local sales rep for Epilog. It might be worth my while to make up a curved surface and have someone burn a pattern of lines on it for me and actually see what the degradation looks like. And perhaps do this with a few lenses. A 2" and a 4' for example. It will be a while before I can arrange to do that, but once I do I will try to take some photos and post them here for the next duffer who comes along asking the same questions.


Dave,


Thanks, That is a nice concise summary of the relationship between Focal Length and DOF.


Thanks everyone! If anyone wants to relate their experiences with where they have found the practical limits in terms of an acceptable engraving on a slope I would love to hear it!


Dave

Dave Sheldrake
10-22-2013, 3:45 PM
Gimme an hour or so and I'll set up a slant job on mine Dave.That should give some idea of where you will be with possible radius engraving (slightly different as a rad is in arc form not flat but pretty good)

cheers

Dave

David Somers
10-22-2013, 4:40 PM
Dave,

Wow. That is above and beyond the call of duty. Thank you!
When i get home from work tonight i will snag a photo of an example piece(s) to post. Got a few hours to go and a long bike ride before I am there though so it will be a while.

Dave

David Somers
10-23-2013, 12:58 AM
So...here are a few photos to show what I was referring to. Just being sure my terminology matches my thoughts.

The first photo shows a possible hollow form that might have engraving done on its shoulders for the sake of engraving by itself. For inlay purposes or for cutting. If it sits on the table of the laser as shown here, the DOF will be exceeded by the slope of the shoulder. One solution might be to do the engraving in bands, each of which stays within the acceptable DOF range of the beam. The issue would be keeping everything matched as you worked, and keeping each band well within the acceptable DOF so there isn't a sense of the banding as you go from good quality engraving to OK quality on the edges of the bands.
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The next file is a small globe for an ornament. This particular piece is about 1.25 inches diameter. I am just using the photo as an example of the shape and a possible solution to the problem of working on a slope.

If you modified your rotary device so that the piece is supported and rotated from the base, and then elevated the far, non drive end of the rotary until the surface you wanted to engrave was parallel to the focal plane of the beam, then the rotary can rotate the piece, resolving many of the issues with DOF on that sloped surface. If you were piercing you would still have the issues Dan mentioned of the wall thickness not being consistent, but that is something that could be dealt with when the piece is turned. I routinely do pieces of consistent 1/8 in walls so for myself this is not a big issue.
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Does that help with the questions i was asking about in this and the post on depth of field?

Dave

Rodne Gold
10-23-2013, 3:33 AM
Its pretty fiddly to set up stuff like that with a laser and ensure consistent results for all situations and shapes.
Even with a long focal length lens and a lot of power , you might have problems.
80w Reci with a 50mm lens and a shotglass that is NOT on a rotary (glass is a product where you can easily see the effects of out of depth of field engraving) you can do a mark of around 1/4 of the perimeter of around a 35-40mm diameter shotglass if you focus on the highest point and then drop the focus a mm or so.. I don't know what the actual DOF is.

Dave Sheldrake
10-23-2013, 6:48 AM
Hiya Dave,

Even with an 8 inch lens (theoretical 12mm DOF) the power density and spot size is going to change quite a bit. DOF isn't where the beam is straight, it's where the spot size is up to 1.4x bigger than the spot so resolution and PD will differ by quite a bit.

I know nothing about wood (apart from a lot of my furniture at home is made from the stuff) so I don't know how badly the engraving will be affected. On metal objects with that kind of surface contour a 4d head or specialist Galvo would be used.

cheers

Dave

Dan Hintz
10-23-2013, 6:48 AM
David,

'Twere it me, I'd set it up as in your second photo... in a rotary and set at an angle. This reduces your problem set to relatively minor ones, such as getting the angle right (easily solved with a spirit level). The major problem will be finding a rotary setup large enough to handle the bigger pieces... and the longer rotaries will also give you problem if the angle is too great (the free end of the rotary will begin to get in the way of the moving carriage). All of that said, file setup itself is easy peasy. File setup for the first method will be a bit painful, not to mention you'll need accurate height measurements for each ring so the focus is good for each.

They both have their downsides, but I think the second method is less error prone once you get the proper tooling (this may mean a custom rotary). Once you have that, everything else falls into place.

Another word of warning... Z depth on a lot of these lasers isn't very much. Smaller systems may only have 3-5", larger systems may be 9-12". Once you've canted the vessel on edge, the opposite end may very well get in the way of the carriage. If you plan on doing larger vessels, you'll need to either purchase a large machine and/or remove the platen and/or cut a hole in the bottom of the machine.

Mike Null
10-23-2013, 6:50 AM
But why would anybody want to ruin beautiful turnings like those with engraving? Sorry---this has been my pet peeve as I'm not one who believes engraving enhances such things.

I would rather see a base with an engraved area.

But to stay on topic I believe each line of the first example could be engraved separately assuming the head of the laser clears the vase. (that can be a real problem) In the second, a properly made device should permit a quality mark.

Dave Sheldrake
10-23-2013, 7:04 AM
Must admit I agree with Mike, adding an "industrial computer controlled" *badge* to a piece of skilled work like that would cheapen it to me. A bit like brush painting a Rolls Royce with hammerite.

I can engrave pretty much anything if I had to but a piece of real art like those Vases takes a skill I can only dream of.

cheers

Dave

Dan Hintz
10-23-2013, 7:16 AM
But why would anybody want to ruin beautiful turnings like those with engraving? Sorry---this has been my pet peeve as I'm not one who believes engraving enhances such things.


Must admit I agree with Mike, adding an "industrial computer controlled" *badge* to a piece of skilled work like that would cheapen it to me. A bit like brush painting a Rolls Royce with hammerite.

To each their own... I have engraved (and sold) a number of pieces over the last year or two, and I've always felt the engraving enhances the beauty of the piece. Of course, you can do things incorrectly... throwing a picture of Snoopy on a sweet burl would be sacrilege, so choosing your subject matter is critical. Western pieces are a good example... nice Arizona-style criss cross pattern can really enhance a piece. And it sounds like David wants to use this for inlay... it would be much faster to create segmented-style pieces using the laser as you can turn a piece whole and then place a pattern over the top rather than creating it piecemeal with small bits of wood glued together, layer by layer. Piercing via laser would also be significantly faster, yet provide the exact same look.

Don't fall into the curmudgeonly ways of "high-tech tools are the devil, purists don't use those kind of tools". Some are content to create using an axe, handplane, and eggbeater drills... others use computers and CNC.

Mike Null
10-23-2013, 7:42 AM
Dan

A curmudgeon I may be but I make my living with computer generated art and I paint in water color and even use gouache, if it suits me, so I doubt that I could be described as a purist.

I'd be interested in seeing some examples of your turnings with engraving. It may change my mind.

Dave Sheldrake
10-23-2013, 7:59 AM
I'm not against either method, I guess I'm more in awe of what some people can do, a gift, a talent like turning a bowl or piece of woodwork or hand engraving something are skills I know I will never have. I get kind comments about some of the 3d models I make on the lasers in my spare time but to me they are just a series of learned responses that pretty much anybody can do given time. On the other hand being able to visualise and create a piece of art has almost a *magical* sense around it.

I've tried for sure, I just don't have that skill set.

A bit like knife making, sure a CNC will do an accurate job of it (and a LOT faster) but watching a master knife maker create a blade from a stock piece of bar is like attending the opera for me.

cheers

Dave

Rodne Gold
10-23-2013, 8:48 AM
I think it will be cheaper and take less time as well as easier to hand chase those patterns , also solves the "made by machine so it's not really art" dilemma :)

David Somers
10-23-2013, 11:10 AM
Its pretty fiddly to set up stuff like that with a laser and ensure consistent results for all situations and shapes.
Even with a long focal length lens and a lot of power , you might have problems.
80w Reci with a 50mm lens and a shotglass that is NOT on a rotary (glass is a product where you can easily see the effects of out of depth of field engraving) you can do a mark of around 1/4 of the perimeter of around a 35-40mm diameter shotglass if you focus on the highest point and then drop the focus a mm or so.. I don't know what the actual DOF is.

Rodne,

That is actually far more forgiving than I would have expected. Still a constraint, but not nearly what I thought it would be. It would be interesting to try a piece like the hollow form I showed, and place it on a shallw turntable with index stops on it so you could rotate the piece manually in small, accurate steps, burn what you want there, and rotate it again. As Dan mentioned, you would have to fuss with your graphic a bit to do that, but once you had it down future setups should be easier. And that would certainly be a low tech way of dealing with it. There was a post here that I found earlier where someone showed a simple jig they made for manually rotating pens for engraving. It was a small index wheel with a stop so the rotation was in fixed amounts each time. The same idea would work here but made with a turntable instead of the setup you would want for traditional rotary devices on an engraver.

Thanks!!

Dave

Dan Hintz
10-23-2013, 12:24 PM
David,

If you're engraving from the top, there's no need for a turntable, your image is just a series of concentric rings. Set the vase directly on the table and laser away, refocusing with each ring.

I think this is the rotary you were thinking of... Ken made it:
http://www.epiloglaser.com/cs_kallenshaan.htm

David Somers
10-23-2013, 1:45 PM
Mike and Dave and Rodne,


For most pieces I wouldn't consider this. And engraving for its own sake isn't what I would be after unless someone asked for it. But I was interested in some of the inlay techniques like veneers, or more likely infill type processes like the metal powder I mentioned. On some pieces a delicate fillagree filled with a silver or brass powder and buffed out would be a nice approach.


I also have a lot of friends in my area who are heavily into their Celtic and Scottish heritage. And others who are into their Norwegian Heritage. There are big...really big celtic festivals and some smaller Norwegian festivals that go on through the year and they have been after to me to do various types of pieces with celtic or norwegian symbols and patterns on them and set up a booth at the festivals. Not something I would want to make a career of, but something fun that these folks certainly seem to want. I would like to see the end result be somewhat organic looking, but use the laser to help make a lot of the detailed cuts that can be so tedious when done by hand. Selling one off hand done items like that at a festival can be pretty counterproductive unless you just don't care about accounting for your time in doing some of the work.


This metal powder infill technique also works well on small Christmas Ornaments. Again, a delicate, thin filagree of silver or brass can be quite striking on the right wood and shape.


Overall though, I just like turned wood as it is and love the figure and feel of the pieces with a minimal finish on them. I have never cared for pieces that have a heavy, plastic like finish on them. I prefer oiled finishes or several thin coats of a hand rubbed finish.


Here is a web site I keep if you want to check out some of my other work. I need to update it badly but it will give you an idea of what I enjoy doing. Nothing is for sale on the site so hopefuly this is OK with the moderators? If not, just holler at me and I will kill the link right away.


http:\\www.turnedwooddesign.com


Like many things along this line, it is the smaller, more "mass" produced items that tend to be your bread and butter, while allowing you the freedom to do the more unique one off pieces that are truly fun and creative.


Piercings is another thing I would enjoy working with. I should clarify that....in wood turning it generally means cutting through a thin walled piece in various patterns, as opposed sticking items through your skin as in the term "tacks and tats"!! <grin> (laser based body piercings or dermal adornments through scarring isn't a niche I am prepared to occupy! <grin>)


Piercings are often used to create the tracery of veins in a leaf or other similar, delicate filagree type of cuttings. Usually done on very thin walled pieces. The wood you use is typically a very plainly figured wood that is colored or dyed to work with the pattern you are doing. One gal I have watched over the years has done some amazingly delicate pieces where the bulk of the wood on a turned piece is carved away and what you are left with is something that looks like a swirl of autumn leaves being picked up in a wind. I wouldn't impose on her style of course, but there are lots of ideas like that that don't involve the more mechanical look of many engravings that Rodne was mentioning, but that a laser might facilitate in terms of the fine cuts being made.


Rodne...the gal I was thinking of is a Botanist from the University of Ohio who does a very large amount of her research in South Africa. She loves the country and the people. She is also a world reknowned woodturner. You might be familiar with her. Andi Wolfe? Check out her work at andiwolfe.com. She is a lovely person if you have a chance to meet her or hear her talk.


So don't worry folks. I am not attracted to the type of engravings that the laser companies advertise in their brochures. I have other ideas for how it can help me without going that route.


Dave

David Somers
10-23-2013, 1:52 PM
Dan,


That helps. I was thinking that was the modified rotary was the better approach to take. I had some thoughts on doing it in a way that eliminated the non drive end of the rotary (obviously don't want to do this on the $1100 rotary that Epilog sells! <grin> but I need to look at rotaries to see their mechanisms. they look pretty simple from what I can see in the photos.


I have been focusing on the Chinese lasers simply because of cost. In the Epilog/Universal/Trotec world the starting costs are stunning, and when you are in a big enough unit to have some Z height you begin to think about selling body parts or family members to fund it. Not a good thing for someone with my level of use in mind.


I noticed some of Rabbits mid sized machines offer a 10 in useable height. That would be doable with a modified rotary for many pieces. And folks on the forum seem to think well of the machines and of Ray Scott.


Still got lots of pondering to do though.


Dave

Dave Sheldrake
10-23-2013, 4:26 PM
Hiya dave,

http://turnedwooddesign.com

Astounding, I only wish I had your skills.

Ray at Rabbit is a great guy, knows his stuff and an all round decent chap who really loves what he does. I've had a few HX machines and of the Chinese models I've owned they have been the best of the bunch. The review I sent you the link to is the UK version of the Rabbit RL1290 (here it's the HPC LS1290)
I can't speak highly enough of Ray, he's got me out of a jam more than once when I needed some weird bits that my local supplier didn't have on hand.

cheers

Dave

David Somers
10-23-2013, 4:50 PM
Thanks Dave! I keep hearing similar praise for him on the forum! Last time I emailed with them Carole answered and she mentioned she had a 14 week old babe in her arms! I think she is a little overwhelmed with that life changing event, but if you folks who know them happen to write in the near future, you might include a congrats to them!!! And be a bit patient with them as well. I am sure they are sleep deprived and overwhelmed with it all!!

Dave

Dan Hintz
10-23-2013, 9:02 PM
I also have a lot of friends in my area who are heavily into their Celtic and Scottish heritage.

Kinda like this? :)

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David Somers
10-24-2013, 12:02 AM
Dan,

Oh yeah. That and many more styles. I will try to keep things a bit more....artistic than that, but we shall see. They are the ones asking for them. At least I have till early summer since that is when the really big festivals come up. I hope I won't get trapped in too many of the festivals. I do love bagpipes, especially the smaller uillen pipes, but I am not sure I could handle many days in a row of highland bagpipe band after highland bagpipe band! <grin>

Rodne Gold
10-24-2013, 2:55 AM
Amazing work by both of you.
Looking at her blog , she was actually in the same town I live in in South Africa , Cape Town ..I have visited all the sites she has pics of
I was thinking , We use a manual pantograph type engraver , a Gravograph TX3 with a rotary attachment to put text and logos on large holloware items like bug cups,
The nice thing is that you can use different cutting bits in it and vary pressure or depth by hand or with a nose cone , far more precise than a laser
It use V shaped bits to engrave , so if you apply more pressure , the engraving stroke can widen and go deeper as the V bites deeper , can lead to some amazing stroke effects and variable depths
You can do flat work on it as well
The rotary attachment is indexed
For complex stuff , I engrave patterns on our laser and then using the follower to trace them which allows the engraving bit put those graphics on the objects.
Depth is no problem as you can see from the pic , you can tilt the rotary as well
Obviously , as the bit is vertical , there is still a limitation as to how much of the diameter you can use before rotating the item
Does all sorts of other engraving as well and will cut shim stock , plastics , will hog, diamond burnish etc etc ---
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Dan Hintz
10-24-2013, 6:08 AM
Oh yeah. That and many more styles. I will try to keep things a bit more....artistic than that, but we shall see. They are the ones asking for them. At least I have till early summer since that is when the really big festivals come up. I hope I won't get trapped in too many of the festivals. I do love bagpipes, especially the smaller uillen pipes, but I am not sure I could handle many days in a row of highland bagpipe band after highland bagpipe band! <grin>

Attended many a festival in my day, kilt and all. Of course, it helped dating a bagpiper at the time. Still keep in touch with her, me passing along bagpipe equipment vendors (such as yourself) and her passing along vendors that fit into my laser and woodworking stuff (she just cost me over $800 after passing along a custom bookbinder I commissioned to do a piece for my parents).

Mike Null
10-24-2013, 6:51 AM
Dan

My compliments on your photography.

Mike Null
10-24-2013, 6:57 AM
Here are some examples of inlay that I find very appealing.

http://www.missionfurnishings.com/category/Inlaid-Plaques.aspx

Dan Hintz
10-24-2013, 8:33 AM
My compliments on your photography.

Thanks, Mike. This is one of the first photos I took when I really started to play with the settings on my camera (used it for the first couple of years in practically point-and-shoot modes), so it's nowhere near where it could be. For example, the dark portions of the wood (and the dark backdrop reflected in the gold) tend to make the edge of the pen less than well defined. A bit of HDR would help, but I'd like to get the settings just right for such circumstances.

I have (what I feel) are better pics...

273650

273651

And this one came out a little darker than I would have preferred... I should have checked it before moving on:
273652

David Somers
10-24-2013, 10:18 AM
Thanks Mike!

Those are lovely inlays. Make me think of an Art Nouveau style. Very distinctive and attractive.

And I like Dan's treatment on the pens. Nice pieces of wood applied to them. And nice pen fittings as well.
Have you played with doing one piece, "desk style" pens at all? Although they are a single piece in some ways they are trickier to do than a two piece pen because of the long, blind drill hole needed (typically 5/32" depending on the insert you use.) One of the fun things though is you have no clip or end cap, or middle band and can be a bit more organic with the shapes, especially the top, where you can do finials or apply any other treatment you think your users would enjoy. I don't do pens often, but when I do my wife will always grab the one piece pens for herself at her desk rather than the two piece. If nothing else, they are a fun variation on project. For what it is worth, I generally just use the insert from a Bic Cristal pen. The drill hole needs to be about 5.25in long, and 5/32" diameter. That will give you a snug fit with the insert. I made a sort of mandrel out of 5/32 drill rod to give the blank some stiffness after it is drilled, and so I have a thickness guage to shoot for on the size of the end of the pen. Other than that....pretty simple. Drill slow and clear often would be my only caution. 5.25" is a long blind hole and it is a bit too easy for the bit to wander.

Sorry.....diverged from engraving into wood turning. <grin> Remember to use a nice font or graphic when you engrave this pen in your UL PLS4.6 60W laser with rotary! (there....thread hijack reversed....whew!!!! <grin>)

Dave

David Somers
10-24-2013, 10:31 AM
Rodne,

That is an intriguing looking machine. Do you have any photos of output from it you were really pleased with? I knew those existed but had never seen one.

If you have a chance to catch Andi Wolfe next time she is in your area give her a try. She is an enthusiastic person and her talks on botany and wood turning have always been fun and interesting.

Dave