V-carving bit slop question

[Chuck Keysor]

QUESTION: Are there big (1" and 2") 90 degree solid v-carving bits ( 1/2" or so 45 and 60 degree) that can actually cut fine lines? (Like .01" in some instances.) If they can't cut that narrow of a groove, what is the best that can be hoped for? How is this parameter specified on a router bit spec sheet, or is it even spec'd at all?

Background:
In an early test, I am doing some very detailed V-carving of an owl, and for this purpose, I recently bought a 45 degree v-bit and a 60 degree v-bit. (The company has been recommmended by users of this site. These bits were made in China.) Yesterday, I used my 45 degree bit for the first time, and was dumbfounded as I watched all the fine lines (some were supposed to be only .008" wide) being cut way too wide! My carving was trashed...:(

When the spindle was finally off, I manually rotated the chuck, and observed that the tip of the bit was not turning on the axis of the bit body! I took this bit, and the unused 60 degree bit, and mounted them one at a time into my drill press chuck. With the drill press turned off, I pulled the bit down and pressed the lightest possible hole into a soft piece of pine. Then I turned on the drill press, and made the lightest possible hole in the wood. This confirmed that on both bits, the tip of the bit was rotating excentrically.

The 45 degree bit static minimum hole size was .027" wide, and rotating, the minimum hole size was .048". So you can see why my carving with some lines that were supposed to be only .008" wide would be all messed up!

The 60 degree bit static minimum hole size was.013" wide, and rotating, the minimum hole size was .066" wide! If you look, you can see that instead of drilling a hole, it actually cut a circle, because the tip of the bit was so eccentric!

As a sanity check, I put an American made bit with replaceable cutters into my drill press chuck. I found the smallest hole I could make with the drill press turned off, was smaller than I could measure with my calipers, it was a pin prick. With the drill press running, the smallest hole I could make was about .004" in diameter.

With all of that as a preamble, I eventually want to carve some large plaques made of oak, with lots of detail. I have read on this forum that some people have had problems with the replaceable bit style cutters breaking in oak. And their small diameters would make the cutting times be even more astronomically large! And with the larger plaques I want to cut, there are areas that get to be close to an inch deep. (The deepest line on my little test owl plaque is only .089" deep, so I could use my Amana replaceable bit cutter there, I just hadn't thought of it before I had my problems with the Chinese bit.)

So, for cutting large oak plaques with lots of detail, I would need some big, very sharp V-bits. Are these available? Your suggestions and advice are appreciated! Chuck

[myxpykalix]

chuck,
check these out:
http://www.magnate.net/index.cfm?event=showProductGroup&theID=117

I honestly didn't read your whole post (borrr-iiing:D):rolleyes: just kidding but here are some 2"+ bits. However i don't think they are as sharp tipped as the bits from www.centuriontools.com.
The difference with centurion bits is they are no bigger then the .5" shanks but they are far more precisely cut angles and better tools, imho:)

[knight_toolworks]

if you are vcarving wood anything less then about .02 deed is not going to work well. it is hard to have the material flat enough and at .01 the depth of cut is pretty sallow and does not show much.

[steve_g]

I use a lot of the Magnate big bits but find that the CMT laser point bits get the best detail... downside is they are only 1/2" CED

http://www.cmtutensili.com/show_items.asp?pars=RB~7/8/958~2

I can no longer get them locally but see they are available online.

Steve

[Brady Watson]

Chuck,
For the smaller stuff, I like to use either a 1/2" 60 deg or 90 deg Mill/Drill. It looks like a combination of an endmill and a v-bit. They are solid carbide and the angles are absolutely exact...plus they run true. You can't use your drill press as a gauge on runout - they are notoriously sloppy, even with a good chuck and quill adjustment. Stick with the spindle to make your measurements.

If you want to engrave at a specific depth (as this will absolutely dictate line width), you would do a machine along vector or 'ON' profile toolpath - NOT a v-carving toolpath. It is imperative that you flatten your spoilboard before machining & machine/engrave your parts immediately after to eliminate fluctuations in Z & inconsistent depths. For smaller projects it is sometimes more economical to put another sacrificial board on the table so that you don't have to machine the whole bed. You can carpet tape or screw (countersunk) a piece of 1/2" or 3/4" MDF and then surface it flat before you engrave your piece. This will give you a nice stable flat area to work in.

I would shy away from all 'mainstream' home-owner type router bit companies for your tooling selection. Start looking at the tools offered by Amana, Onsrud and metalworking tooling companies. The metalworking tools are dead on and held to a much higher standard than router bits. I like Harvey, Micro100, SGS and OSG. Get your machining area (bed & machine) tip-top, then start analyzing the tooling results. If you don't get your XYZ dialed in properly, your tests will show faulty results.

-B

[Chuck Keysor]

Thanks Jack, Steve, Steve and Brady for providing your helpful feedback.

a) Sorry for my long description, but I often get confused by short postings that don't give enough info, and somehow I tend to over-compensate! I hope that others will continue to add suggestions.

b) I later realized that for my concentration on the trees, that I had not discussed the forest. To that end, I have attached an image of what I am trying to carve (and hopefully I won't stop getting input on my original question). The owl image is a woodcut print, from around the year 1500. A number of years ago, I took a class in art printing, and really enjoyed it. But the issue of actually carving the wood printing plate (MDF was the standard material) was mind numbing. You take a new photocopy of the existing image you want to print, lay it on the blank MDF printing plate, then soak it with acetone, to transfer the image to the MDF. Then you have to carve away all of white areas of the print. This can take endless hours and hours to carve even a simple image. So I want to use my Shopbot to improve this process, so I can focus on the images, and not the carving.

I like many old woodcut prints and want to be able to print them using real ink, on great paper. On some images I have worked on, they are clearly based on the original image, but I tend to revise them, to correct things a woodcarver in 1500 couldn't do when he slipped. He didn't have plastic wood (or Photoshop!). So I am not out to even make exact copies by any means.

Since I like these images, I also want to be able to directly carve them, as I am now starting to attempt. After I can get the process down for making regular plaques, I will move on to making reverse image printing plates. Or that is my hope. (Each printing plate can make tons of prints, so the long carving times are small on a per print basis. The plaques, that are just single copies, are instead just for my own enjoyment since they would be cost prohibitive to hope to sell with such huge cutting times.)

With that explanation of the forest, I hope I can get some further feedback that will help to steer me away from disaster and dead ends.

Thanks again, Chuck

[steve_g]

Chuck

I tried to do something similar a few years back... I V-carved away all but what I wanted to print and to use it like an ink stamp. I was disappointed with the ink stampings...My results were never flat enough after carving in solid wood (warping from carving) to stamp well. I always intended to try it with a linoleum block but never did...

Steve

[knight_toolworks]

not sure but you might get away with doing these in mdf. if everything is very flat. but plastic or other hard material and a drag point may be the way to go. but that requires a spring loaded tool.

[myxpykalix]

I think they call that "woodcuts"? I've never tried that but it looks interesting

[Chuck Keysor]

The print making class I took at my community college spent probably 1/3 of the semester on wood cut print making. The standard material for making the printing plates was plain old MDF. The teacher praised it for its uniformity, low cost, ease of carving, stability and large sizes.

Some students made woodcut prints that were at least 3 feet by 3 feet. These were artists, so they drew their artwork by hand right onto the MDF. (And they took into account that the final image would be reversed when printed. Well, usually they did!) Then they carved away all the white areas by hand. The printing block was then carefully inked up, the paper layed on top, and then it was run through the school's large format flat printing press.

The process, as you might imagine, is very low tech. But as with any skill, there is a lot of technique to pick up, like how to apply the ink, what types of ink to use, preparing the paper, what pressure to set the press at, etc. But this is all fully covered in just one third of a full semester.

As to the diamond bit, and dragging that on a printing plate, that was another printing technique. I think it was called dry point, and we did that on a copper plate. With that technique, everything is made with super fine lines, that are very shallow. The copper plate is inked up, and then all the ink on the surface is wiped off with only ink remaining in the finely scratched grooves. Essentially, this is the opposite of wood block printing, where you don't wipe off any ink as the printing is done by the remaining flat surfaces. The copper plate engravings require a higher printing pressure, and is a much more touchy process. Again, it was fascinating in its own way, but I was more intrigued by woodblock printing, because I liked so many of the old time German woodblock prints.

I have never seen a posting on using the Shopbot for printing, though I haven't searched. When I took my printing class, in 2007, my teacher, with his MFA in printing, had never even heard of CNC machining. I discussed my idea with the graduate teaching assistant, who was on his way to an MFA in printing, and he scoffed at using a machine to do the carving! He said it would remove the art from the process.

[adrianm]

For really fine work I use three flute engraving cutters. They can cut a very fine line and when doing deeper VCarving they leave really crisp edges.

As I'm from the UK I get mine here - http://www.wealdentool.com/acatalog/Online_Catalogue_Engraving_60_degree_719.html - but I expect there are plenty of US suppliers as well.

[Chuck Keysor]

Back to the point of making a printing plate with a drag bit on a copper plate,,,,, I have attached our one class assignment made using that technique. All of the fine lines you see were made with that method. But since my fine lines were simply too fine, I had to go and hack and chop with my diamond point scribe, to try and make wider lines. This print also has a number of other techniques, like acid washings, etc (I don't even recall, but we had to use multiple techniques for the assignment.) so the print is kind of gloppy. And, I do not have the hand eye coordination, or the touch of an artist to do something like this well free hand.

As a note, the assignment was to make an image that tells something about your life. A few months before, I had been laid off when the company I worked for was effectively closed. It was my first job, right out of college, working as an electronics designer for a company called Dukane, that started in 1979. In 2002, Dukane was bought by EST. And in 2005, EST was purchased by GE. So you will see all those names in the print. The sunrise represents the cheerful optimism of my youth, (and and the company's original logo when founded as OPERADIO in 1922 included a fancy art deco sunrise). The grimey drain, and nasty bugs represented my age altered view of things after being laid off. (We were told we could re-apply for our jobs if we were willing to move to Florida!) So the title of the print is I Feel Drained. In addition to the obvious drain in the grimey floor, there is a drain in the circuit as well.

But copper plate engraving would also lend itself very well to the Shopbot. It would make it so people like me with poor hand-eye coordination could make something that looked reasonably acceptable. HOwever, it was my feeling at the time, that printing with copper plates was much more challenging than for woodcuts.

[myxpykalix]

chuck,
check out widgetworks for a drag bit to make your thin engravings or if you need something thicker in places check out centurion for their 120 degree vbit. That thing is sharp and comes to a great point and will stick you and make you bleed:eek:

I think i recall a famous woodcut of a morris print?. It is a woman walking thru a field. I believe that is a woodcut. I have seen pictures somewhere of where guys have cut this and it looked great.

[GioAttisano]

I think the high quality woodblocks were cut into endgrain, especially boxwood. Now more commonly maple. Keeping an endgrain slab flat is a trick, and might require great thickness, and some care to flatten first, before engraving, when you know for sure it has equal moisture throughout, and then keep it that way. But you can get get much better detail in endgrain than facegrainwood, or I would think MDF.

[steve_g]

When I tried it a number of years ago I was using the face of maple... I rolled the Ink on with a brayer roller and pushed the block face down on some paper... I didn't know to try a press! The higher quality MDF will hold remarkable detail, that along with some sort of press makes me want to try this again! If I start now, maybe I can have Christmas cards ready by December...Maybe.

Steve

[Chuck Keysor]

Thanks for the interest in the printing. As I recall from printing class, the wood that is to be cut away, to leave the white areas on the finished print, needs to only be cut down 1/16" to no more than 1/8". In addition to MDF being a good material for fine detail and being easy to carve, linoleum is also used for this purpose.

I did some on-line checking, and there is good information on the Dick Blick web site. They have some basic, but good videos, and they sell ink, brayers, papers, and anything else one would need.

I have some comments on other interesting replies others have made, but will wait until tomorrow. Chuck

[steve_g]

Well... I just couldn't wait to try it! The MDF was a scrap that had been sitting around absorbing moisture for quite some time and it still worked many times better than when I tried it last... Also I didn't have any Ink so I sprayed some Red spray paint at it and hand stamped it. Very promising indeed!

Steve

[Chuck Keysor]

Per Brady's request, I went back and measured the sharpness of my USA made carbide "In-Groove" RCK-360 bit in my spindle. Turning the spindle by hand, the smallest diameter mark I could actually cut, was around .005" dia. (Measuring this small with my dial calipers is a little subjective.) But it was a tiny pin prick, put non-technically.

I first painted a piece of ultralight MDF, as it was clean and very flat. I had my RPMs at 13000, and a feed rate of 3ipm (setting in Aspire, so maybe the Shopbot followed this setting, I forgot to try and check, but it looked like the bit was moving fairly slowly.) The lines that were cut looked to be appropriately narrow. So at first I was encouraged. But as the cutting continued, the surface began to get all fuzzy, and in places, the MDF surface just crumbled away. (This seemed odd, as the cuts were shallow, and roughly speaking, the narrowest lines were about .010 wide, with a bit more than .020 between the closest lines.) This problem showed up fairly soon. After letting this run for about 30 minutes I ended the test.

Since I felt it may have been a mistake to use ultralight MDF, for my next test of cutting the owl image, I used a piece of 3/4" good plywood, with maple veneer, and what seemed to be a very hard, smooth factory applied finish.

I didn't stay and watch, but came back 30 minutes into the test, and the surface was fuzzy, but the lines also looked to be too wide. I looked at the end of my new, expensive replaceable bit, and it clearly had lost its sharp point! Yikes, sigh.....:( more money wasted. (Other posters had complained about these bits breaking in oak, but not MDF or plywood. These cuts are really shallow, and happened somewhere in only 60 minutes of running time.) I remeasured the tip, and it is now cutting about .030 for the minimum width. So now, I don't have a good sharp tip to even do my testing with.

I will thankfully, at least be able to go back and read through your recommendations, and look for a good SHARP V cutting bit.

After I get some sharp solid bits to test, I will repeat this test with regular MDF, and some melamine. In looking at Doug Haffner's post about his middle Earth map, he used a sheet of PVC. Maybe that will cut without falling to pieces. But I don't know off hand where to buy PVC sheets.

Chuck

[twelchPTM]

i buy my all my plasticcs from Total Plastics inc. I know they have locations across the us but not sure how close to Elgin they are

[Chuck Keysor]

As noted on a post to Jack Jarvis, as of late, I have switched over to using "VCT" vinyl composite tile, aka kitchen floor tiles. They stay flat using my Widget Works pressure foot, and hold great detail, at least enough to carve the Owl image I posted earlier.

The drawbacks though with this material is that color selection is limited, to colors I mostly don't like..... And all the grooves get plugged up with "gunk"/residue vinyl that I can only remove with an Xacto knife. For fine lines, this is intensely laborous, taking a couple of hours on some of my more detailed carvings.

But my CMT "laser" 60 degree bit has been fabulous for this work! Chuck