V Carving Cedar Help

Hi,

I'm just getting started using my new (to me) ShopBot. I've made a nice vacuum jig to hold down boards while I machine them and that works well. I have a Porter Cable router which I bought new - I think it's the 3-1/4 or 3-1/3 hp one. Has a switch along the top to let you select 10k, 13k, 16k, 19k or 21k RPM. I'm able to make sign designs with vCarve Pro 7.5 and export them to the ShopBot. All is well up to this point.

And mostly it carves well, but it tends to tear out the wood. I'm using a new carbide, 90° bit, 1-1/2" wide bit. Seems nice and sharp. I've tried different speeds on the router but it doesn't make much difference. I know cedar is pretty soft. And I don't remember where the settings for that bit came from. Attached are photos of some carving I've done and the settings for that bit.

Ultimately I want to make signs where I paint the top after carving and sand the surface leaving just the carving black - nothing earth shattering. Now I end up with poor edges and ragged places where the woods been torn out and the paint tends to wick along the grain. Not very satisfying.

I've tried figuring out the correct settings but I'm not very confident. I could use some advice about how to improve things.

Thanks!
Attachment 31772
Attachment 31773
Attachment 31773

Hello Steven. Welcome to the forum. I can't really read your speed setting,,,,, I kind of think it looks like 200 inches per minute...… I always do my V-carving at 1 to 1.5 inches per second (60 to 90 IPM). The bad news is that your cutting looks terrible! The good news is that your cutting looks terrible, so bad, that I think it will be easy for people to tell you what is wrong.

When I first started cutting, I had never seen V-carving before, and I thought what I had was not very good, because it wasn't perfect. And the little bit of imperfections I wanted to get rid of was hard to figure out, and I mostly just learned to ignore the little bit of chatter that I had.

I think people are going to want to know your settings right off the bat, so if you could repost your setting so they are big enough to read, it will help. And people will also want to know what brand of bit you have. Your wood looks more torn then cut, so the bit may well also be adding to your disappointing results.

Good luck, Chuck

Sealing the wood before carving will help some with tear out and a lot with the paint bleeding issue. The corners of the letters are not crisp indicating that the bit is not true 90 deg. Try telling the software that the bit is 89 or 91 deg. I can't read your speed settings either but try Chucks recommendation. I would try a different font to eliminate that ridge in the middle, but that's just me. A lot of folks here like the CMT laser point bits for vcarve.

Thanks for the help!
I can't seem to post a picture that's any larger than what's in the OP. I'll just list the settings then.

Diameter: 1.25 in
Included Angle: 90.0 deg
Pass Depth: 0.5 in
Final Pass Stepover: 0.0163 in / 1.3 %
Clearance Pass Stepover: 0.25 in / 20.0 %
Spindle Speed: 12000 RPM
Feed Rate: 100.0 ipm
Plunge Rate: 30.0 ipm

I'll try figuring out the exact angle of the bit - here's the link. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

It seems pretty nice - sharp!
What do you use to seal the wood? That seems like a good idea.

And what about router speeds? I've tried different speeds and none seem to make it better - I think something else is the big contributor.


Oh, and the corners aren't supposed to all be sharp - attached is a shot of the toolpath.
Attachment 31778

Slowing it down to 60 ipm helped quite a bit. I'll try slowing it down further. Most of those ridges along the center of the letters are intact, but some still rip out a bit.

Attachment 31779

Just to make sure the machine and parameters are not to blame, do an experiment with some more forgiving hardwood like maple or cherry. I have had mixed success with softwoods and even with the same species some pieces are more or less likely to tear out.

So the pass depth is .5 inches ? / you are doing all this in one pass ? Perhaps a bit deep and loading up the bit too much ?

sign master / Oklahoma Joe uses a layer of rubber cement on his surfaces before v carving I believe.

It seals well for the painting stage and is removed as the last step.

Steve I think you need to get your carving under control before you worry about paint bleed. You have a vertical grain cedar board that is going to chip out very easily. Look how wide the growth rings are on your board. try to find boards with a narrower pattern which will come from a slower growing tree or an older tree. next you have to run cedar painfully slow (40-60) ipm. I would turn that pass depth down to .2 or maybe .25" and a last pass at .010. Another option is to use a different species of wood. Some of my favorites are walnut, cherry, white oak, Spanish cedar, African mahogany. There are some finishes that work well but no clear coat that I am familiar with will last even a moderate length of time including spar varnish. Once you are happy with your carving we can help you with stopping the bleed.

Quote:

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Originally Posted by stevenblake

Thanks for the help!
I can't seem to post a picture that's any larger than what's in the OP. I'll just list the settings then.

Diameter: 1.25 in
Included Angle: 90.0 deg
Pass Depth: 0.5 in
Final Pass Stepover: 0.0163 in / 1.3 %
Clearance Pass Stepover: 0.25 in / 20.0 %
Spindle Speed: 12000 RPM
Feed Rate: 100.0 ipm
Plunge Rate: 30.0 ipm

I'll try figuring out the exact angle of the bit - here's the link. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

It seems pretty nice - sharp!
What do you use to seal the wood? That seems like a good idea.

And what about router speeds? I've tried different speeds and none seem to make it better - I think something else is the big contributor.


Oh, and the corners aren't supposed to all be sharp - attached is a shot of the toolpath.
http://www.talkshopbot.com/forum/att...id=31778&stc=1

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Sanding sealer, shellac, then carve and seal again before paint. The sealer will help some with tear out, but the other recommendations will also help. Those tails at the corners are where the bit is supposed to emulate a hand chisel going in from the corner. Should not be round. Not trying to be critical just wanting to help.

One more thing you could try for such soft/brittle wood is a burr bit. That will not tear into the wood with 2 or 3 flute edges but rather grind it to a fine powder. I have used that on cheap and brittle redwood with good success. You may need an air jet to remove the dust and avoid burning the bit and go slow. It won't work well if the wood is resinous and clog the bit grooves.
Something like that:
Attachment 31780

Dear Steven

For my two penn'orth I suggest reducing the pass depth to 3mm or so and increase the RPM to say 19K. Checking chipload calculators would say these (3mm and 19K) are out of range and may burn the cutter. But as you are using this 'Quarter Sawn' (vertical grain cedar board) soft cedar you could give it a go.

Have a look at the end grain of your boards and see if you have any tangential sawn ones and give one of those a try and compare it to the quarter sawn. I'm sure you will see a difference.

Anyway I'll watch with interest to see how ir works out for you.

Sincerely and in good faith
Martin

PS Check the cutter is still in good nick after all this messing about.


Attachment 31783
image acknowledgement guitartimbers.com

Steven,

Good suggestions by all.

Of all the carving techniques using a V bit is a wonderful challenge. It's extremely delicate. I love getting the delicate wire lines it gives.
To do serious work you will need a VCarve program. One that articulates the bit. Without that it's going to have a clunky image.
Looking at your attempts I'm thinking your problem may be the bit. Onsrud is one of my favorites.
Try lowering the bit into the material and toggle it around at different speeds.

Best of Luck

Joe
www.normansignco.com

http://www.talkshopbot.com/forum/att...id=31784&stc=1

http://www.talkshopbot.com/forum/att...id=31785&stc=1

http://www.talkshopbot.com/forum/att...id=31786&stc=1

Joe, can you weigh in on some feeds and speeds and other similar (or different) techniques you use when VCarving? Any particular bits that you run that offer better cutting performance over others?

For good performance in carving like that I'd start out with 2.5 IPS and about 12k RPM.

I would also recommend taking a looking at your ramps. Often time when VCarving the settings on your ramping can cause the machine be a bit "snappy". You can essentially make it a bit more gentle by dialing back some of the ramping speeds. It's not a magic bullet, but it might help. As others have said too, perhaps something with a tighter grain would be a better choice for material.

Check out this article from Brady: http://www.shopbotblog.com/2008/03/a...m-performance/

It's a masterclass in how to tune the ramp rates in your machine.

Eric,

Your suggestion for feeds and speeds are about right.
I'm thinking the problem is the bit. Onsrud is my choice. I use VCarve Pro. Perhaps he should visit Vetric, Vcarve Pro and post over there.

Not at all sure this is a thread for me.

http://www.talkshopbot.com/forum/att...id=31788&stc=1

http://www.talkshopbot.com/forum/att...id=31789&stc=1

Joe

In response to the questions about the Waterford Letter Style I believe it comes from the LHF font Desire. Created by Charles Borges de Oliveria. This one has the Glyphs package.
It's been my habit to purchase the best fonts on the market. That, by it's self, can set one's work apart.
www.letterheadfonts.com

http://www.talkshopbot.com/forum/att...id=31787&stc=1

Nobody asked about the font... Are you on the wrong thread again? Either way I don't think new fonts are going to solve the problem :)

Steve did you try looking at ramping or trying some tighter grained material?

With Vcarving in solid wood and plywood, I have taken to like the setting 90ipm XYZ at 12k rpm with my machine (see sig line for specs). I mainly us a 3/4" wide Freud vbit. It leaves smooth edges that don't require much cleanup. I'd much rather it take a little extra time on the machine than spend time doing hand work. I have ran things as fast as 180ipm in plywood that turned out ok, especially if you've masked the flat part with vinyl and are going to spray paint the carved areas for a rustic look.

All that being said though, I think most of your problem is the soft wide grain quarter sawn material you're using.

Quote:

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Originally Posted by joe

In response to the questions about the Waterford Letter Style I believe it comes from the LHF font Desire. Created by Charles Borges de Oliveria. This one has the Glyphs package.
It's been my habit to purchase the best fonts on the market. That, by it's self, can set one's work apart.
www.letterheadfonts.com

http://www.talkshopbot.com/forum/att...id=31787&stc=1

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Joe, do you have any problem with LHF vectors ? Their fonts really look great. Jerry

Jerry,

Letterhead Fonts are premium and glitch free. Chuck Davis is the founder and reviews every one. He's always available to help with any problem.

It's neat to know all these letters are made by practicing sign artists. For years most of these have only been for sale by LHF. Another advantage is, the memory bank maintains fonts you purchased so if your computer drops the fonts, they are available at no charge.

One precaution about the letter style "Desire". It's huge. It took David eight years to build and for sure professional designers tool.

www.letterheadfonts.com

Joe

Steven Blake:

How did you make out with your tests? Looks like a common thread that people are saying is roughly 2-3 IPS and about 12k RPM. Also, using some tighter grained wood seems to be a common suggestion. I'd be interested to see how it all turned out for you.

Quote:

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Originally Posted by joe

Jerry,

Letterhead Fonts are premium and glitch free. Chuck Davis is the founder and reviews every one. He's always available to help with any problem.

It's neat to know all these letters are made by practicing sign artists. For years most of these have only been for sale by LHF. Another advantage is, the memory bank maintains fonts you purchased so if your computer drops the fonts, they are available at no charge.

One precaution about the letter style "Desire". It's huge. It took David eight years to build and for sure professional designers tool.

www.letterheadfonts.com

Joe

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Thanks for the push Joe , I will be doing business with these pros. Thanks again. Jerry

Steven Blake,

I'm with Eric, how's it coming?

Joe

My two cents. I've made thousands of vcarved cedar signs (used to take my smaller CNC to the Christmas fair every year and make signs to order - fun and hectic). Sharp bit, 60-70ipm, 15k, mostly Artcam toolpaths which basically carves each side of the groove separately, don't know about Vectric, about every font that you can imagine. 2002 PRT w/upgrade box. Very few issues like pictured. I was carving into blanks prefinished with Helmsman Spar Varnish, so it may be a coat of Shellac or other sealer may help you. And, as mentioned in an earlier post, I tried to buy clear, vertical grain cedar, though always ended up with something of a mix of grain patterns. Don't know if any of this helps, just wanted to post a system that works for me.

On a side note, I had a lot of issues with bleeding, the worst was kinda borderline to me, but nobody ever complained. Best results were consistently with close growth, vertical grain, worst with flat grain. When in the shop, using a mask and spraying the vcarve with shellac before painting helped a lot on prefinished blanks. Raw wood, shellac before and after vcarve helped.

Donn,

Like you I've carved tons of signs without anything like what's been shown. Using ArtCam Insignia with hardwoods, soft cedars, redwoods, MDF, and Trupan I can't remember any problems.

Those of us making a living at it move past errors like this with speed. Note all the suggestions with no photo examples. This is a visual business and suggestions are more effective if seen with a snap or two.
Joe