Redwood V Carving Tips

[Walt_S]

I've been trying to work with some redwood and it's been really hit or miss. I've carved with different bits and with all of them I'm getting "pockets" down in the V, on the sides. I really wouldn't call it tearout, I don't know what it is. Haven't seen it in any other kind of wood, maybe it's the nature of redwood?

The latest one I cut had tearout on the surface, it wasn't too obvious until I painted the letters and sanded it off.

I was under the impression that redwood was easy to work with but I'm not finding that to be the case. I was under the impression that cedar was somewhat difficult to work with but I'm not having any trouble working with it.

I would post a couple of photos but my phone and computer are not talkin gto each other at the moment. :rolleyes:

Any suggestions would be much appreciated.

[Walt_S]

I got them to make up so here's some pics.2953529536

[Burkhardt]

Redwood does that. The dark growth rings are quite hard but the lighter material between is very soft and brittle and can be ripped out easily. A super sharp bit will minimize that tearout but I find it never will be really smooth. On a flat surface you can sand it out easily but for a Vcarve that will be difficult. You may try cutting a few 1/1000" high first and then a finish cut at the final level to improve that. Another idea (I did not try that) would be a finish cut with a coarse v-burr instead of a normal v-bit to get more of a grinding effect.

[Walt_S]

Thanks for that info. I was wondering when looking at the second picture why the tearout seemed to be concentrated in a straight line. I did notice the wood look lighter in that area. I wonder if sealing it with some spray on shellac before carving would help. I have seen that recommended for cedar although I haven't had the need so far. Some say it sort of glues the fibers together and helps prevent tearout. Worth a try I guess. I will also give your idea of a finish cut a try. Since this on is pretty much trashed I may go back and try to cut it again a tad deeper.

[Burkhardt]

The shellac or other wood hardener may work. Just make sure it penetrates deep enough. If it is only a thin hard surface skin, you can make it worse.
Keep in mind that Redwood quality varies a lot. You can find pieces with wide growth rings and lot of the brittle stuff or you can get dense material that is usually also a lot heavier and carves nicer. When I buy redwood lumber I pick through the pile to find good pieces.

[Walt_S]

Thanks. That's good to know. I was looking for interesting grain patterns, but I guess I need to be looking differently now. I was surprised how light some of the wood was compared to others. I will look through my stock closely now before cutting. I also think I will give the shellac a try. I use it after carving and before painting to seal the edges and make it easiet to sand off, so a couple coats before are worth a try. Thank you for the valuble information.

[Chuck Keysor]

Hello Walt. Thanks for the interesting post. In looking at your picture, it does look like the problem you have is associated with the grain of the wood. I have marked your photo to accent the different grain zone.

But I also wondered if there was a connection to the move speed of your bit. When I watch my machine moves while V-carving, the Inches per second move rate, is of course constantly changing, ramping up and down based upon Aspire taking into consideration the up coming curves, etc. So I wondered if maybe you were getting tear out associated instead of with the grain, it was instead with where the bit may have been moving at its fastest IPS rate.... Or maybe it was a combination of the grain with a high linear move rate? This is just my idle speculation.

While you were watching the V-carving being cut, did you notice if the bad areas correlated with the bit moving at its fastest rate?????

Thanks, Chuck

[Walt_S]

Hi Chuck, thank you for posting. That is a good question that I don't have an answer for.

Firstly, I use VCarve Pro, I tried to add a signature but it's not showing it. I don't know if that matters or not with the move rate between VCP and Aspire.

Secondly, with the dust foot on my machine, a DeskTop, I can't see what is happening, so I don't know about what, when, where, etc. as it is cutting :)

So I don't know, but it is an interesting thing to consider, although I'm not sure how one would work around it.

What I can add, is I was cutting at 17000 RPM at 1 IPS, which is what I cut cedar at usually. I know they are different woods, and I have a lot to learn, so maybe I need to adjust some settings also.

Thank you.

[Chuck Keysor]

Thanks Walt for the follow-up detail that your max speed is 1 IPS. I had been wondering if you were at 3 or so IPS, and that most of the time, the actual speed was less on the curves, and maxed out on the straight-aways, creating the tear-out. So you have eliminated a theory, making the grain of the wood remaining the most likely cause. (It was very interesting to note how the grain changed within the band that I circled, and that is where all the chipping took place.) Chuck

[Burkhardt]

You made me curious since I have not done much vcarving in redwood and I did a quick test with a scrap piece of very soft con-heart 2x4. I used a cheap (but very sharp) 1.25" 60-degree bit from eBay. I like that because I can vcarve serious depth without making waterlines.

A) 1.25ips and 12krpm one pass there is serious tear-out
29538
B) 0.6 ips, 12krpm but 1st pass 0.01" high and second pass at full depth: almost no tear-out (2nd image) however some chipping of fragile protruding features (3rd image)
29539


29540

My conclusion: redwood is just too brittle for such stuff, maybe except for larger carvings without small features.

[Walt_S]

Chuck, I was thinking about your post last night, if you look at the straight lines in my second photo above, the painted version, there was no tearout what so ever on those lines, which went all the way around the piece. There was also some smaller text with the same font below the shown text with no tearout. So I think we can probably conclude it is the grain indeed. I recut that text last night with a different 60* bit and used a start depth of 0.01" to see if it might clear someof it up. It did, but it left some new tearout places, too, although not as bad. Both bits are fairly new and sharp.

Burkhardt, thanks for the examples. I was thinking of some other pieces I carved for Christmas gifts. They were from a different piece of redwod, which looking at it last night is noitcably darker and has much finer grain than the one above. I also cut them with the grain running vertically instead of horizontally. They were both a large font cut with I think a 1/4" 90 bit. I'll have to find the pictures, but they turned out perfect. So maybe you're on to something with your last sentence. Lol, maybe if I rotate my design 90* and turn the board with the grain running vertically it will help. :/

Btw, do you have a link for the ebay bit? I buy some of mine there with good success.

[Burkhardt]

I bought mine a few years ago for $6 but it looks like similar ones are nowadays only $1.58 with free shipping. http://www.ebay.com/itm/60-Degree-Router-CNC-Engraving-V-Groove-Bit-6mm-x-22mm-1-4-Shank-22mm-Tool-mw-/322349768719

Quite ridiculous but the one that I bought back then works absolutely fine. Sharp carbide, maybe 15/1000" tip width and no unbalance. That said I do not run it over 12krpm due to the heavy head and slim shank.

They say 1/4" shank but it is actually 6mm and a 1/4" collet will not work well.

[joe]

I love carving Redwood.

I haven't had problems like those shown. I'm suspicious it's the bit. On this kind of work you should have the best, sharpest cutters on the market. And they should be be kept sharp. Second, if you take a look at the example posted in, "First Sign" you may notice the redwood is vertical grain. That was done on kiln dried stock. I've found kiln dried lumber is much less likely to have tear out since the sap have been converted.

My favorite is the 120 degree bit. It doesn't cut very deep on letters with a heavy stroke. A finish pass is always a good measure.

Joe Crumley
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[Walt_S]

Thanks Joe.

So the wood in my photos is mixed grain, correct? Does vertical grain carv better than mixed grain? And it is kiln dried. I believe after looking at my stock the larger 1x12 is vertical grain and that is what I had cut previously that turned out well. Since I have no lumber yards close to me I can't be too choosey, I have to pick from what they have. But I'll look closer at the grain now. Is there a trick to cutting mixed grain versus vertical grain?

[scottp55]

Joe,
Was it you that said when you went through the stack, you always looked for as close to vertical grain as possible, and tightest growth rings unless you were sandblasting?
Walt's looks like the edge of the heart/sap line flat sawn and close to horizontal growth rings.
I noticed with a couple softer hardwoods, that the pith layer falling exactly wrong for small VCarving and 3D's caused problems, and was wondering if clear vertical grain redwood was better cutting.
scott

[Walt_S]

I found one of my Christmas plaques that turned out well. This, as is the other piece, is sold as "kiln dried heart B redwood D4S". I wish they had rough cut like they do their cedar, but it's better than nothing, if I can carve it that is.

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edit - I had carved the above using the same bit I carved the one this post is about, it is an 1/8 60.

[joe]

Walt,

There's a couple of advantages to vertical grain. The first reason is our signs are exterior. When the grain is on end it's less likely to warp and split. But most of all, when sandblasted, it will carry more detail and show wood texture best.

Perhaps you could look, on the web, for "Kiln Dried Redwood" or "Clear Heart Redwood" to get a better idea. Since you aren't using much of this kind of wood I'd suggest getting the cost delivered to your shop.

Vertical grain does not mean the grain is close together. I have used construction grade wide grain redwood on some projects. Also I've used common grade Yellow Pine vertical grade with success. I love that wood and it's cheap. It will not crack or split, even though it's not kiln dried, if you choose the vertical grain boards. What I do is go to the end of the boards to choose. I'll see if I can fins a photo.

[scottp55]

You can see by where in the log it is affects the growth/pith rings.
You want it to look as close to Quartersawn end grain pattern as possible probably.
The round plaque looks close to rift sawn:)

[Walt_S]

Thanks Joe, between your explanation and Scotts pictures I know what to look for now.

Thanks Scott. I was just looking at some of those diagrams myself. :) I think I got it now and know what to look for. As for what I have on hand I have to figure how to deal with. :(

[joe]

Scott's illustrations are excellent but what you should consider is how close together the growth rings are. For V carving you want tight grain. But still, I think your main problem is the bit. Try a Onsrud 100 or 120 and I think you'll be surprised.

Joe
www.normansignco.com

[Walt_S]

I tried a 90 I have becasue of Joes suggestion. It did cut a lot cleaner. The 90 is the same make and age as the 60 I had used, which may or may not mean anything. So what is it, the angle of the cut that doesn't produce as much tearout? Main problem with this one is I'm matching the font from a business card and a 90 or greater isn't going to get into the fine parts of the letters. I was barely getting there with a 60.

[joe]

Walt,

I would encourage you to compare the detail rendered with a 120 degree to a 60 degree bit. The sharpness and detail should be the same but the readability from distance will increase with the flatter angle. I've found the sharpness of these bits to be extremely critical with this kind of carving.

Onsrud offers these bits with a 2" wide diameter. That's so important when working with beautiful wide stroked letters like Caslon Graphic or most any of the Black fonts. The letter quality can also make a difference in the outcome. What you and I have to do is make lots of tests in order to refine our techniques.

Joe Crumley

[Walt_S]

Joe, I'm not doubting or disagreeing with you. However on this particular plaque, which is only 5.5" x 12" with a very fine and narrow calligraphy type font, a 120 bit is not going to work. Even a 90 bit looks totally wrong. I need to be using a 60 at the most. The 90 did cut nicely, but it won't work for this application. I will try to post some example in a bit.

[Tom Bachman]

I use the 37-82 which is the 60* V. Which number are the 90, 100, and 120 degree bits? The listing on the web page shows nothing but 60* bits. http://www.cncrouterbitsxp.com/toolsxp/pc/37-80-c155.htm

I would like to have other choices, but don't seem to find them on the page. I'm hoping that you guys tell me that the 37-87 is 90*, the 37-92 is 100* and the 37-97 is 120*

[Walt_S]

Page 19 has the standard V bits info https://www.onsrud.com/files/pdf/OC-12-ProductionCuttingToolCatalog.pdf

[joe]

When I discovered, a few years back, the extra machine cut in the tip section of Leitz, Gerber and Onsrud Vbits I haven't used any other cutters. It could be this is standard machining for bit manufacturers today. But this little machining inclusion seems to clean out small detail better. Without that little cut in the tip a V bit operates much like a common flat paddle bit.

Sharpening: I've not been all that sure about having bits re-ground. The "Sharp" life of a bit depends on the substrate one carves. One thing for sure, when I'm carving on wood that's been blasted, the life is short. I have two of these to do in a couple of weeks. It's a yellow pine project I've done before.

Joe

[Walt_S]

Here is the plaque in question in whole. The name was cut with a 1-4 90, the spacing is off because they are spaced to be cut with a 60. The small "Stylist" was cut with an 1-8 60. The small text represents the font on the business card perfectly, the name text looks like an elephant next to a mouse, even if I spaced the letters to be cut with a 90 they are too big and bulky for this font for this purpose. I have ordered an Onsrud 60 conical engraving bit to see if it might help with the tearout.

29552

[Walt_S]

When I discovered, a few years back, the extra machine cut in the tip section of Leitz, Gerber and Onsrud Vbits I haven't used any other cutters. It could be this is standard machining for bit manufacturers today. But this little machining inclusion seems to clean out small detail better. Without that little cut in the tip a V bit operates much like a common flat paddle bit.

Joe

Joe, what do you mean by this?

[joe]

I'm sure your bits have this little cut in them.http://www.talkshopbot.com/forum/attachment.php?attachmentid=29568&stc=1

[Walt_S]

Hmmm, interesting. I've never seen that before in a tip diagram and my 9x magnifier isn't going to get near that close to see that.