Raised Letter carving in cedar

[kmich59503@yahoo.com]

I have recently been assigned the task of creating some cedar signs with raised letters I have made a street sign for a local appartment complex, they liked it so much they ordered 18 more signs. The problem I am encountering, is that when carving my signs the last pass around the text causes some chipping and feathering of the wood. Are there any suggestions out there to prevent this from happening??
I am using a 1/8" upcut 2 fluted carbide bit at 19,000 rpm with a move speed of .75 IPS
Any advice is greatly appreciated!

[gerald_d]

Hi Ken

1. Go anti-clockwise around the outside of letters (clockwise on the inside).

2. Do NOT start (and finish) your cut on a sharp corner.

3. A straight flute cutter will give a better top edge than a up-spiral. A down-spiral will give the best results.

4. Consider doing away with the "clean-up" cut. (We never do a "clean-up" because it caused more problems than it cured - as you are discovering)

We would use a 1/4" down spiral, cutting 1/4" - 3/8" deep per pass, at 25 000 rpm and 1.5 IPS for this application. But, I don't know your cedar, or your router size (our router is only around 1 HP). For street signs, a 1/4" bit should still be perfectly acceptable??

[rgbrown@itexas.net]

UH, what Gerald said.......

Good advice.

Ron Brown rgbrown@itexas.net (mailto:rgbrown@itexas.net)

[rick]

Anyone use the formulas from Vortex to determine speed and feed rate?

[rgbrown@itexas.net]

"Anyone use the formulas from Vortex to determine speed and feed rate?"

Tell us more and where the find the "Vortex" formulas.

Ron

[gerald_d]

We have one formula for wood: If it sounds right, then it is right.

For plastic: If it looks right, then it is right.

Seriously though, there are so many differences in:
- hardness of material
- sharpness of cutter
- free play in router spindle bearings
- rate of dust/chip extraction
- firmness of clamping system
- tolerable noise level for shop
- desired quality of cut for a particular application
- time pressure due to looming deadlines
- etc., etc.,
that formulas can only a very rough guide for somebody venturing into the complete unknown. Your own gut-feel soon replaces formulas.

[david@thecarpentershelper.com]

A Sharp bit, and to keep the bit sharp as fast of a speed as you can cut the material this will help reduce heat build up. I use an old bit sharpened then push it till it is ready to break then back off a little then write those speeds down for that type of wood. sounds crazy but it works. many guys try to sloww way down and some materials you have to but the faster you can cut the cleaner the cut and the less heat on the bit causing it to burn up. David in Wyoming.

[david@thecarpentershelper.com]

Also Ken try using a non carbide bit this sounds funny but cedar causes a break down in carbide. and that causes the bit to dull very fast. you see cedar has an acid content in it that carbide dosen't like that is why when you get a splinter in your hand it festers real quick also make sure you use a good resperator for your lungs even with a good vac system cedar dust will really chew up you lungs real fast. I sugjest using red wood if you can to help avoid these proublems. Dave in Wyoming.

[david@thecarpentershelper.com]

One question I have for Ron and Gerald.

When do you guys sleep?

[gerald_d]

at David!

Agree that the highest spindle speed always seems the best for all woods. It is only for plastics that we slow down the spindle. (we don't cut metals - yet)

I sleep from 10pm to 5.30am, in Cape Town, South Africa. We are 7 hours ahead of the time shown on this Forum.

[rgbrown@itexas.net]

UH, Sleep?

Actually, I sleep between 10 or 11 PM -sometimes as early as 9 PM and get up sometime before sunrise. I haven't used an alarm clock since June 30, 1980 except when absolutly necessary.

Of course, at times I will get up in the middle of the night and I do some work. And, as my shop is connected to my home, I post at any time I feel I like.

Ron

[david@thecarpentershelper.com]

Thanks for the insomnia report guys I just thought I was the only one that ever worked all hours,LOL David in Wyoming.Gerald next time I'm in Cape Town I'll look ya up. LOL-LOL-LOL

[signshop@post.com]

Hi Ken et al,
I had the same problem You have, namely chipping out the last cut on raised lettering. I assume you create the cutting files in Vector using the "Pocket Z Contour" option. I use this option but first I perform a full-depth offset of the lettering making sure I am not climb-cutting either the interiors or exteriors. I then connect at z and convert to .sbp.
Now I can delete the selected outlines and do my normal pocket z contour without a finish pass.
Works well for me.

[gerald_d]

Hugh, thanks for explaining that a bit better than my short "do away with the "clean-up" cut" above. Yes, FIRST cut the outline of the letters, once on the final size, THEN pocket out the excess.

This is true for all pocketing - not only for letters.

David, (and everyone else), I would love to offer a "Camp ShopBot" here in Cape Town - except we will probably have to call it "Safari ShopBot"! LOL

Seriously guys, you are all very welcome to come and spend a day or two (or three) hanging around here. A steak and a bottle of red wine will set you back $10 in a restaurant . . . And you can tell the IRS it was a business expense trip!

[KMICH59503@YAHOO.COM]

Thanks for all the suggestions, I plan on doing major amounts of signage starting Mon. morning will try out some of the Ideas.

Hugh, the program I used to do the sign programing is the Parts Wizard program, It is a very simple process in this program to do raised lettering. I just set the size of material, create text, box in the text and click the icon for "area clear", set the appropriate parameters as far as tooling goes and "viola" I have a cutting file. Also with this program I can edit the tool data such as step down, move speeds,and step over percentages, which makes it very easy to experiment with different materials..
Thanks again all for the suggestions if anyone else has any feel free to keep em coming!

[kmich59503@yahoo.com]

Does anyone know if there is a way to carve the letters out first with the shopbot parts wizard program, without making it too complex and/or time consuming. I like the simplicity of the area clear button where the program figures out the complete pocketing program, but if there is a better way that would be "almost as easy" I am open for all suggestions.

Ps. I also have Vector 9 installed on the computer that creates the cutting files for me, just haven't had the time to completely learn that program yet.

[sleepy]

Ken
I use part wiz. everyday to make signs. I design in Corel export out as a dxf import into Part wiz. and let it do the tool paths. and save it as a shopbot file Then run it Do you want your fonts raised or engraved. As far as time I can do a residential sign in about a hour Design,tool paths, run, and paint.

[david@thecarpentershelper.com]

Ok guys I found a bit that sounds interesting. it is supose to eliminate the need to do two passes. that is 1 for each depth. it is called the vortex tonado you can see it at www.vortextools.com if any one has used this bit let me know otherwise I'll let you all know david In Wyoming.

[peter.j.meacham@lmco.com]

David - I am not finding any reference to Vortex tools on the web and "www.vortextools.com" does not find a working web site. Do you have any other information on where to find info on these bits please. Thanks, Pete

[ron_cleaver]

I found the web site at www.vortextool.com but I couldn't find any information about the tornado product.

[billp]

Try this page:
http://www.vortextool.com/standard/productGroups.cfm?catID=52
(When in doubt Google it...)

[gerald_d]

That is an expensive bit - can it be resharpened?

[rgbrown@itexas.net]

If you'ld just listen to the salesman, you would know it cuts forever and never breaks or dulls.

[pappy]

Pete
Try this:

[srwtlc]

I've been using their up and down cut finisher spirals (series 1200 & 1300) for a few months now, and I would say that they are the best bits I've used so far. I haven't had to resharpen any yet, but they say that they can resharpen them. They will also resharpen other manufacturers bits. The nice thing about them for me is that they are local (approx. one hour away).

Scott

[gerald_d]

The "scalloped" edge of the cutter is the part that makes me wonder about resharpening.

We haven't found anybody in South Africa that will properly re-sharpen our spiral Belin bits. The Belin factory in France will resharpen at about 80% the cost of a new bit - not economical until we have about 50 bits to send back.

[david@thecarpentershelper.com]

I'm glad you guys found the web sight This bit is very expensive but it takes the place of two bits one for roughing in and the fine finish so I guess you could say it is really two fo the price of one, if that make you swallow any better. any way at the speed they are talking about it would really cut down on time even if the Bot can't come close to those speeds in inch per min but I run mine alot at 2ips so if my math dosen"t fail me that means 180 inch per min and a far cry from what thy say the bit will withstand, and as we all know or should know "the faster the feed rate the less chance of heat therefor longer life of the bit". David in Wyoming

[gerald_d]

2 ips = 120 inch per min
3 ips = 180 inch per min
Yeah, its way past your bed time

[david@thecarpentershelper.com]

Gerald You get an A+: I wanted to see if anyone was paying attention. I guess that is the old teacher in me. and yes I know my spelling can be better at times, I get my brain and my fingers going at different speeds on the keyboard. David in Wyoming.P.S. Well I said I work all hours, I was at My Shop when I wrote that.

[danbrewer@attbi.com]

I think the "tearing" that occurs when routing cedar is for the most part unavoidable (as it is with Aspen, Soft Maple and all the other soft woods).

I've done some signs using the dog-eared picket fencing you get at Home Depot with good results. The wood is REALLY moist, but if you slow the head speed way down to about .4 ips you can get good results. It's a cheap alternative to buying cedar blanks.

One other note about plowing out the areas around the letters is the small swirls the end mill bit caused by the head changing directions too rapidly. I set my ramp speed ratio to about 20% to avoid it. It's a tradeoff, of course, when time is money and you're trying to push a large order out the door to use these slower speeds, but quality vs. time is always a tough tradeoff.

Speaking of keeping track of time, I was pleasantly surprised to discover that the ShopBot software gives the "total time" of the job in the lower right-hand corner after the part file is complete. Guess you learn something new every day.