V-carving questions

[tgrand]

6303
Hi everyone! I'm a new ShopBot user with a Benchtop PRT and PartWizard 2.0. I've been given the task of carving letters into about 60 wooden signs to be used for trail directions. I'm supposed to aim for a result similar to the old signs, pictured above, and I've been given finished and cut pine to work with, also pictured. This is all completely new to me, and while I've read a lot of helpful forum posts, manuals, and other info on the web, I still have some basic questions I hope you can help me with:

1) What bit should I use for V-carving? I need to carve letters that are around 2-3" tall with a depth into the wood of about 1/4-1/2". I've been asked to make the letters as rounded as possible, like the old letters. Should I get a ball-nosed bit, and if so, what diameter? Or should I get a V-shaped bit, and if so, what angle?

2) I plan on using the default values in PartWizard for spindle speed, feed rate, and plunge rate for whatever bit matches closest to what I end up getting. But how can I tell if/how these values should be adjusted? I've read that you generally want a high spindle speed and low feed rate, and should be ending up with chips and not dust, but I could use some advice on what seem like very important parameters...

3) What's the easiest way to paint the carved letters while still maintaining good quality? The wood I'm carving into is already finished. I've been told to try using paint mask, but based on my reading here I have concerns about how well V-carving through the mask will work. (This goes back to question #1.)

4) Any ideas on what kind of paint(s) to use? The letters are supposed to be painted yellow like the old ones, and they'll need to stand up to the cold, snowy winters and hot summers of northern New England.

5) Will double-stick tape work to hold these signs down onto the benchtop while V-carving them?

Any answers or other tips would be greatly appreciated. I've done some design in PartWizard and a test cut (small area clear) on some scrap and the ShopBot worked beautifully, so I want to buy whatever bits and supplies are needed and move ahead with this project. Thanks!

[jay]

Tom, for the painting refer to http://www.talkshopbot.com/forum/messages/315/4716.html?1096208504

For the letters, in the picture, it appears that a ball nose bit was used for both the large and small letters. I would use a single stroke font and machine along the vector for the letters through the mask then paint as per above link.

[bjenkins]

Tom,

It looks like your sign blanks are stained. One option for painting would be, DON'T. You might get really good contrast with the light letters on the darker blank. Just put a poly finish over everything when you are done.

As far as the cutting questions:
Jay is right, but it can be harder than it sounds to find a single line font. It is worth it because you will use it again. The v-carve will have much more of a 3d effect. I prefer the look of v-carve, but it will not match the old signs.

Also, don't try to start on your good material. Go buy some MDF and cut some test blanks. It's cheap and ideal for practice. Better yet, get some pine (less dust and more representative). You can get some #3 pretty cheap and cut around the worst spots.

Bud

[joe]

Tom,

Well it seems you have lots of good advice, so let give you a thought or two.

The examples you posted are not V Carved and I wouldn't suggest it. I believe the font is "Half Round Block" whic is easy to do with a strait double fluted bit. We must have done a couple hundred of these and they money makers.

We would make plywood hold downs for the corners of your panels which would be screwed to the bed.

Painting: This is a easy one. We use a Veterinary Hypo Syrenge, one of the large ones, cost about .60 cents. Suck up the paint, and fill the well of letters.

The proper paint would be a catalysed automotive paint, such as Centari, or epoxy with a couple of tea spoons of One Shot for color. Either way they will dry overnight and last for years.

We put a 2" strip of masking tape along the bottom line of letters. This allows us to move from letter to letter without drips.

If you are concerned that the paint will soak in, as sometimes it does, a very light coat of Shellac applied with a small brush will seal it off.

Wish I were there to give you a hand.

J

www.normansignco.com (http://www.normansignco.com)

[jay]

Tom, Bud, may I suggest some test with blue or pink foam first. It is cheaper than MDF. I purchase all the damaged sheets cheap from Home Depot and or any of the other big box stores.

[normand]

Like Jay said use single stroke font but a bit deeper spraypaint the letter and pass the board thrue a planer

[normand]

Sorry I just realise your board is allready finish

[tgrand]

Thanks for the tips, guys. I don't have to match the original letters - they're just to be used as a rough guide. So, I was asked to use V-carving, presumedly to save time(?) and because it looks good(?). I guess I'll have to try some test cutting with and without V-carving to see what the differences are in process and results. We have plenty of scrap wood already from an unrelated construction project, although it's not pine...

The V-carvable font "Lucida Sans" in PartWizard seems adequate. So, doing some toolpaths for 1.5" tall letters, I get:


6304

I'm still wondering what to buy for bits. The toolpath for V-carving appears to be the same whether I use a V-bit or a ball nose bit. If I use a V-bit, I don't know if 90 degrees is ok, or if I should do 1/4" or 1.25" for the V-bit diameter, or what. If I try to do V-carving with a ball nose bit, I'm not sure what diameter it should be. I'm kind of hoping to avoid buying bits that don't work out for this project.

[bjenkins]

Tom,

There are lots of tips on the forum for good source for bits. You will find a variety of opinions on v-bit angles and there are pros for 60, 90, or 120 degree bits depending on the specific case. Bear in mind that the depth and width of the v-carved geometery scales with the size of your letter. The bigger the letter, the broader and deeper the vee. That can become an issue in a couple ways. If your vee width exceeds your bit diameter, it requires more passes (and precision time) to cut the letters. The deepest part of the vee can get very deep with a 60 degree bit. You can do the trig and calculate the depth verses width for any included angle easily. When you calculate the toolpath you can also see the final z depth. The choice of font also comes into play.

I'd suggest you create a toolpath with each tool and get a feel for the difference in PW. Then get the bit you think works for you. (If you are like most of us you will eventually get several, but it is nice to spread the expenses out.)

Oh, one more thing. I like the her-safe v-bits a lot, but the 1.25 diameter barely fits through the hole in the dust collector attachment. It is great for really big letters, but I prefer my 1" diameter for most cases.
Bud

[joe]

T.

Bud is correct about the stroke of the letter. Although we use Artcam, and can limit the depth of the stroke, I believe you will find the width of the storke of the letter determines the depth the bit will plunge.

The reason I suggested on a flat bottom letter is that it is soooo easy to paint. V letters take much more time and skill. Try both and you will see.

j

[paco]

I select the angle from the largest width of the lettering; example, if you use a 90 deg. on lettering that is 1.5" width at some points, you will dig 0.75" in the pannel... if you want to V-carved a letter that is 4" width at some points, you'll surely want to use something like 120 deg. Software calculate the cutting height of the toolpath from the diameter of the bit knowing that it vary according to its height portion (being small at tip and large at end). The results should be both good but different.
I don't think that a ball end is suit to "V-carving"... is it?!

[beacon14]

Tom,

What you may not realize is the fundamental difference between profiling and v-carving. The profiling toolpath is merely "tracing" the outline of the letter, but offset from and parallel to the font outline, at a uniform depth of cut. You can use almost any cutter, as long as the cutter diameter at the surface of the cut is the same, the shape of the tip wont make that much difference unless the letters are large, especially from a distance. If you try this with a V-bit, however, any minor variation in workpiece thickness, table flatness, etc. will translate into a variation in the thickness of the letter, so a straight or ballnose bit usually work best.

With V-carving, the cutter is being continuously raised and lowered so that the diameter of the cutter at the workpiece surface matches the thickness of the letter at each point along the letter. The tip of the cutter pulls right up to the surface at the "corners" of each letter, allowing the finished letter to look like it was hand-carved. If you try this toolpath with a ball-nosed bit, you wont get the desired results. In PartWizard, you should have had to select the cutter, and therefore the cutter angle before the software would create the toolpath. That's the cutter you need to use with that toolpath to get the desired results. Of course, you can always try it with another bit and see what it looks like!

If all I am doing here is stating the obvious, forgive me.

David B.

[paco]

The obvious is too often ignored or forgot!!! It's good to have different views with different explanations of the same things...

[gerald_d]

Tom, your client has supplied you with finished pine blanks? That immediately waves a red flag against doing a V-carving job. As David explained above, the depth of the cut determines the width of the "stroke" of the font - pine blanks are seldom flat, and you are not going to know how deep the cutter is really going in.

Your starting point on this job is to check how flat your blanks are. My gut feel is that true V-carving is a non-starter for this job.

However, I would still purchase at least one V-bit for experimentation. 60 degree bits are less fussy about flatness than 120 degree bits, but they cut a lot deeper to get the same stroke width. 60 degree bits often have a sharper tip than the others which are sometimes flattened off. The bits with replaceable tips never cut a sharp-cornered groove.

You won't regret buying a 60 and a 90 degree bit with a sharp tips, diameter probably around .5" to 1.0", but maybe you won't get to using it on this particular job.

[Mayo]

Since you have about 60 signs to do, I would try and use the "cut through the masking" idea because it can help you paint quicker.

Make sure you Z zero to your sign blank surface before you put the masking on if you are using a thick masking like sandblast mask. For vinyl masking, it won't make much difference since the vinyl is so thin.

If you use water based paint, try to get a masking that has a solvent based adhesive. This way the paint won't soften/dissolve the adhesive of the masking and there will be less chance of paint creeping under the mask.

For paint, I would first use exterior latex primer for bare wood and then use exterior latex house paint. Most good brands of house paint are supposed to last for 20 years or more.

I would not recommend putting a clear or polyurethane sealer on. The only thing that will do is make it look shiny for a short time. Then the sunlight and UV rays will attack the clear coat, it will change color, and eventually peel and flake off, leaving your signs looking like a bad sunburn.

V-carving will look more classy and more formal than doing the same letters with a ball nose bit, which will give them a softer look and a little more casual. Also the ball nose bit will make a letter which may need repainting less often because there are less sharp angles and crevices to hold moisture from rain, snow, etc.

Hey Joe:
Did I meet you at a Letterhead meet? Maybe Belvidere IL or Mazeppa MN or Vinton IA or Milwaukee WI ? I have a business card here from your shop... At the time I may have had my shop vehicle "painted" with black beauty smalts on one side - and a huge bar code along the other side. Signs By Mayo was my shop name.

[tgrand]

Thanks again for some very informative posts! I have a much better idea (I think) of V-carving thanks to your help. I ended up ordering a 1/8" ball nose bit and a 90 degree V-bit for testing.

As for the blanks, they are finished and they seemed very smooth but I'll take a real close look.

Also, I now realize that 2D profiling inside the letters won't work, and I understand the single line font recommendations. I'm going to try doing some letters with the 2D area clearance strategy and see how that goes. Once these bits show up, I'll do some tests with and without V-carving and post the results.

This forum is great!

[gerald_d]

On this website (http://jat.esmartweb.com/cape-town.htm) you can see the most-photographed sign in Africa. (Ball-nose cutters (two sizes), centerline (or single-stroke) font, on marine ply)

They actually have two signs, one on display and one back at the workshop, and they get rotated a couple of times in the year to make sure they are always perfect for the tourists' photo's. We were offered the contract to make the local park signs (including this one) but the contract is too big, and it includes the fieldwork and maintenance/rotation.

Normally the tourists stand behind the sign while someone takes their photo for them. The sign is about waist height. Notice the rock - it is for someone in the back row to appear a bit taller.

[fleinbach]

Gerald,

That smooth hill area behind the city looks like a whale. I see an eye, a fin, and a tail. Is this just my vivid imagination?

[gerald_d]

That is a wonderful observation, and the very first time I have heard anyone say so! Well maybe I should point it out to the locals and see if they want to rename Lion's head (the tail) and Signal Hill (the head)..... That particular view is from Robben Island, and only a few people (mainly prisoners) were able to see it as you have done. The more common view (http://www.capetownskies.com/0708/17_lhead_city_ri_saddled.jpg) is from the city center where the whole thing looks like a lion lying down on its side with one ear pricked up (the back end of the lion is Signal Hill to the right). But it is whale season now, and they do visit around here

[joe]

Mayo,

Perhaps we have been crossing paths. Yes I did go to the last Muster. I have been a LH since the "Bash" at Jacksons back in 1980. My shop was about a mile from his back then. He is a good friend and I need to visit Darla and him before I get too old.

What are your next Letterhead plans. Perhaps we could finally meet.

I have enjoyed you posts on Letterville and here, which are chucked with good hints.

J.

www.normansignco.com (http://www.normansignco.com)

[kerrazy]

Tom,
as the leeters will be 2-3" 's tall, I would suggest a 90 degree v-bit with a 1.25 diameter. These are available through your Gerber dealer and I would also at the same time pick up Gerber Mask 2 from the same supplier.
As the sign blanks are finished, you will then just be able to apply the mask, secure the blank to your table Cut very quickly, and literally paint and prime with a mop. Make sure you use either a good quality acrylic latex exterior grade house paint, or One Shot chromatic yellow. This process will make the job very easy.

An important thing to remeber though is to Z-Zero your tool for each sign blamk, as inevitably they will differ slightly in thickness.
Good Luck
Dale

[vcabinet]

If I am doing 12" letters in 3/4" wood. What steps should I take not to go through the wood? Can I vcarv? I have many bits for this. Most of my work is panel work. I need a new business sign for my building.

[ron brown]

Gary,

I have a car. It is blue. What size tires do I need?

You will need to supply more information if you want an answer. Even better, you could use "TypeSetter" and answer the question yourself. Hey! how about that?

HTH,
Ron

[paco]

Unless your letters are very thin, you will need to use a VERY wide inclued angle... or adjust the depth of the cut in the software V-carving strategie settings... or you could simply use a V-bit (one that have a not too wide inclued angle.... still, depends...) for the perimeter of your letters (and cleared the interior with an "area cleared" strategie); that's more easy with most software and you can "control" the depth of the cut related to the "area cleared" depth setting (this way though, you will not get "sharp" corner/details)... depends on what your looking for?!

How about that?!



By the way Gary, your WWW site is... WOW!

[workingdog]

Can anyone tell me were I can find a "old english" font. That I can V carve.
I am working with an older PR machine.

Thank You in advance.

[paco]

You can try www.whatthefont.com (http://www.whatthefont.com) and www.typenow.net (http://www.typenow.net) as for finding fonts... as for V-carving 'em, it depends on your CAM software and bits inventory...

Hint: sometime, doing a deep search on your PC can reveal some great findings... use the Windows explorer and look in ALL folders of ALL your installed software... you may find fonts that are not installed on the window font folder...

[jsfrost]

PW2 will vcarve any of 10 fonts, even after limited editing. Is there a specific rule to determine which edits are allowed and which are not? I do a series of edits combining script letters to make a smooth flowing word, then the Vcarve toolpath either runs or it doesn't. I never know until I try.

[paco]

I believe you can't ungroup 'em to V-carve 'em... Maybe doing each letter seperatly can enhance the possibility...

[billp]

For those of you who have been looking for a reasonably priced 120 degree V bit, MLCS (800-533-9298)is now carrying them.
The bit is 1.25"wide, and it has a .375"depth of cut. For those of you new to sign making the wider/flatter angle of these bits makes gold leafing much easier, and it also helps to reflect any metallic lettering paints you may use. It's their part # 5423, and it costs $28, ( NO shipping charges these days with MLCS...).

[joe]

Great post Bill.

Sometimes a deliclate script or intricate letter style, carved with a 90 degree bit looses visability because the wall of the letter are too steep. It should be understood that the depth of a letter, when using a 120, is reduced but the width of stroke remains the same as a 90. All you have really done is flatten the font.

As Bill mentioned, this comes home when using 23K

J
www.normansignco.com (http://www.normansignco.com)

[jsfrost]

I am cutting several signs for the local city park. The blanks are 2x12x72 (1.5 actual thickness) and have 8 inch letters, stretched slightly in width to leave roughly 6 to 8 inches uncut at the ends. We did samples using a 120 degree V and the customer was very happy with the appearance.

As a last minuite change, it was decided that two of the signs should have text on both sides. More money for me, but the present toolpath will show daylight where text overlaps both sides.

What is a reasonable cut depth on each side to maintain the sign's strength?

How best to maintain the look and feel the customer likes, while restricting the cut depth? Shallower V, flat bottomed V or?. Insignia would be my toolpath choice.

Jim Frost

[ron brown]

Jim,

http://www.hersaf.com/cutters04.html - Her-saf has V-bits in 10 degree incriments from 90 to 170 degrees.

Ron

[paco]

Jim,
you could try a 135°V (or more wide angled...)

you could flip a copy of the design on the one you wish to carve to evaluate where the "depper" part will "align"... and probably position 'em to avoid engraving to overlap...

Good luck!

[rookie432]

Hmmmm....
Outdoor signs Vee carved on both sides. My experience has been that removing material from the face of the sign guarantees that the wood will cup to the face side. Removing material on both sides of a 1.5" board might really weaken the board. The easiest solution would be to cut 2 signs 1.5 " thick and laminate back to back.
More structurally sound and probably cheaper than a special bit as well as adding structural integrity.

[billp]

Maybe even include an internal lamination of something like an aluminum coated board (.25"-.5") to further add stiffness as well. Of course this means putting a cap around the edges...

[Josh Perkins (Unregistered Guest)]

Ron,
Are these the same bits,
Josh
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50387&item=4358236 456&rd=1&ssPageName=WDVW

[ron brown]

yes

Ron