V Carve question

[nick]

Having problems with good results on any lettering...please help.

Using Partworks...

60 degree V bit (from the starter kit)
Using 20% on the clearence and 5% on the final.

Cutting speeds @ 1"/sec for X, Y and Z. RPS @ 15000.

When V carving without flat...Looks OK...would accept it for home...but not for sale...

When V carving w/ flat tool (.25")...letters look terrible. It does the first trace around all letters (Century schoolbook)ok so far...when the bit lifts up to do edges...you see tool paths in material...and we it goes in to clean up edges for A's...you see tool paths all over...this sucks...I've adjusted VR settings that helped some...

Does my step over need more adjustment / fine tuning, I'm at a loss...

Do I have a sloppy Z (It's 3 months old with very little ware).

I hope a standard can do better than this...any other standard owners have this problem...I hope none.

Wood is maple.

[jamesgilliam]

Nick, I have done quite a bit of V carving. Could you post a picture of what it is doing? James

[sawdust535]

Nick
I had the exact same problem. Try using a Final Pass of 0.0065 (1.3 percent) and a Clearance Pass of 0.1 (20 percent). I also tried a 60 degree 1/2" V-Bit from Centurion with far better results over the Onrud 60 degree 1 inch bit.

[paul_z]

If you get better results with another 60 degree bit then the problem is likely to be that the first bit you are using is not really 60 degrees. Unfortunately, this is quite common.

http://shopbotwiki.com/index.php?title=CheckVBitAngle shows what happens with relatively small errors in bit angle for a 90 degree bit. It also shows how to find the effective bit angle which can then be used specified in your software to make use of the off angle bit. The example is for 90 degrees but you can easily do the same for a 60 degree bit.

Paul Z

[sawdust535]

Paul
Thanks for that info, I am going to run that file. I'm still experimenting with different bits and parameters. What angle bit and parameters do you find best for small lettering (1/4" to 3/8" high) on both soft and hard woods?

[jamesgilliam]

George, On that small of lettering I would stick with the 60 degree bit. I have routed the entire song, Amazing Grace, all seven verses, on a 8" x 11" plaque, several times with good results. The text was just under 1/4".

James


8294


8295

[myxpykalix]

Nick,
like George said he got better results with www.centuriontools.com (http://www.centuriontools.com) bits and probably the cheapest way to help figure out your problem is to try their bits and eliminate that aspect of your problem. Look at the point on this.

8296

[GlenP]

My 1" bit in the starter kit was not 1" as well. I measured it and it measured .91. If the bit is not the same size as the software thinks it will toolpath to the diameter set in the variables. Measure that bit angle and diameter and adjust settings to match. Good Luck

[sawdust535]

James
What kind of material was used on those plaques above. Also, the feed rate, spindle speed, final pass stepover and clearance pass stepover.
Jack
I just purchased several bits from Centuriontools and have been really pleased with the results. Excellent customer service too.

[jamesgilliam]

George, Material is agathis, which has become impossible to find now in my area. I have an older PRT, 2001 model, so my feed rate may seem slow to those with the newer machine. It was cut in one pass at 1"/second, router at 10,000rpm. I used a bit from Woodworkers Supply, 60 degree, three flute.


8297

Sorry about the fuzzy picture, camera doesn't like close ups. It is the only one I use for this kind of work and it is one tough bit. A bit on the pricey side, but worth the extra $$$. My wife has run a plaque with this bit before and forgot to turn on the router, and it CARVED its way through the agathis without damage to the bit. If she would not have told me about it I never would have known from the way the plaque turned out.