If you are running a #302 and your letters are 1" in height, your sample cut points to the Z not being properly zeroed.
Note: When I zero my V bits I take a small piece of paper or backing to Velcro/ double sided tape and lower my Z until its just barely over, then adjust to .01 and lower until bit just grabs paper and allows to spin, no further as your cuts will end up gouged when it would otherwise come out looking rather clean.
I will switch to phone and add image of test cut
I am running a file now, scooped up your image and converted. While my conversion was not perfect, here are the results.
Single cut, # 302. Cut center is @ center of material.
Be sure to barely kiss whatever you use to zero IE- piece of paper. Get the V bit close using 1mm, .1 then final approach using .01 can be used…
This is essential or job will not come out properly.
Paper should spin on center radius but not move xy.
Thanks for that. I don’t have a #302 cutter, just using a 60 degree bit from Inventables now. I do notice on yours and mine, that the smaller letters actually look better. They have straighter lines. If you’ll look at mine, you can see that it’s most dramatic on the N. Also, at the top and bottom of the N, it looks like the cutter missed a pass and just left the outline there. It looks like a serif font. Very weird. The O also has a weird misshapen part of the inner circle on both yours and mine. Looking closer again, ALL the letters have that weird serif.
I’m just doing tests in luan, but that shouldn’t matter, right?
How wide is your 60* bit at its widest point? and are you sure it’s 60*, my #302 1/2", 1/4" & 1/8" 60* v bits all fit in the profile of the letters fine.
I see what your talking about on your O, mine is not like that, kinda looks weird in my photo but its cut through a knot in the wood and looks perfectly round.
You may want to go through your machine and check v wheel tightness, belt tightness etc… basically the daily chores.
If you want just clean letters for the bigger ones, I find finding the largest bit that will fit in the pocket to provide a clean cut and use that.
A 1/16th SE 2FL Endmill would fit inside General Store and provide a very clean look.
That very much looks like something moving where it shouldn’t, in amounts that would seem to be in excess of what I’d expect from deflection. As Mike says, I’d definitely check out belt tension and v-wheel fit as those are the likeliest culprits. Somewhat less likely is the stock itself moving - how do you have it held down?
If all of those are fine, then I think you get into the weirder stuff, like the stepper motor gears being loose. I say “gears” because it looks like the errors are in both X and Y directions - it seems unlikely that both would be loose.
So far, I’ve rechecked my belt tension and all seems ok (though there really is no way to know as there’s no actual way to know just how tight they are).
There is no deflection when I try to move the bit in the spindle, nor can I really make the carriage move in any direction when I try. The whole machine just moves as one, which seems to indicate the assemblies are all tight. The V-wheels seem tight as well. The stock is held down by 4 clamps and is not moving at all.
My 60 degree V bit (specs attached) is .23 inches wide.
I just carved an N and an I. I watched the bit as it went. I can actually see it making those squirrely curved moves. Like there is something wrong with the code or the interpretation of the code.
The original letters in “GENERAL STORE” are about .125 inches wide, again significantly less than the bit width.
As far as the simulation goes Will, it doesn’t reflect at all what it carved. Attached is a JPG of that as well. Thanks in advance for all your help!
Hi Will, I haven’t tried the inset yet as it seems likely that there is some other underlying issue.
Attached is the screen grab of the tool and the file as well. N and I.nc (6.7 KB)
Sorry - here’s the definition from the tool creation menu and another carve of the same letters in a different font, which seem to me to exhibit exactly the same issues with the N as the other font.
Here’s the full carve. Still a few anomalies (the top of the T and the top of the S, but it’s SO much better! Should I expect that level of accuracy, or can I do better somehow?
Belt tension — the Z-axis should be guitar string tight (but careful not to bend the motor shaft): http://docs.carbide3d.com/assembly/shapeoko/xxl/step-5-belting/ on deep cuts it may help to remove one spring from the Z-axis temporarily, esp. if one hasn’t added a spoilboard on top of the wasteboard — it also helps to install the router as low as possible (installing the Makita adapter upside down will help). Some folks have found it helps to remove bolts which won’t stay tensioned (M4 Z-axis tension bolt, various V wheels with eccentric nuts), apply a thin bead of threadlock along the length of the threads, then reinstalling. See the video at: https://www.youtube.com/watch?v=_lIIb_PdziA Note that the X-axis motor is held in place on standoffs and if those bolts are loose this can cause belt tension issues.
It is also important to be sure that the collet is correctly tightened, the endmill fits correctly and doesn’t slip, and the router is mounted securely in the mount, and that the mount doesn’t shift. Note than endmill pullout can happen gradually, especially when profiling against tall walls.[4]
Maybe I missed it, is your bit really 6mm, or is it 1/4” (6.35mm)? If it’s really 6mm do you have a 6mm collet or 1/4” collet? Is it a 1/4” bit that you’re defining as 6mm? That tiny little 0.35mm makes a difference.
Hey @DanoInTx, he posted a drawing of the bit in a post above. It has a 3.175mm shank and a 6mm max cut diameter.
@philiphack I’ve used those bits from Inventables on a different machine. The angle was closer to 58° than 60°. Unfortunately, you may have to fine tune it with tests. Setting your zero accurately on flat stock is also very important.