Tolerances?

So…I was having issue with depths being correct when cutting detailed projects.

Some places in my acrylic that are supposed to be complete cut throughs did not cut through while other areas cut past the acrylic and into the under-board. Also noticed that when the project started, in some places it wasn’t even touching the project until later into the path and then would drag across. Its just hard when you cut a hole .52 for a part that’s .5 and the part still doesn’t fit.

I’m using the Z-Probe - X-Controller - 1000mm - dewalt 611 - precision 1/8th cullet
I recalibrated / adjusted my v-wheels and belt tension, re-homed my machine, etc.

I then downloaded the test calibration project and ran it on some MDF. Here is what I got which is weird - seems like its going deeper now.

Easel Setting ------ Caliper Reading ------ Cut
.3 .309 Square Outline
.25 .268 Circle Outline
.1 .114 1st Tiny Circle
.15 .163 2nd Med Circle
.2 .217 3rd Biggest Circle
.4 .415 Large Circle Outline
.35 .375 Triangle
.25 .279 Large Circle
.05 .089 Small Rectangle
.15 .185 Med Rectangle
.2 .234 Large Rectangle

I guess my acrylic could be that different in widths (hard to measure the center of piece) but wanted to ask if this is normal or should I be attempting to dial it in more? If it should be closer to actually marks, what should I do to dial it in tighter?

I KNOW these are very very small fractions - but trying to be very tight to fit things super tight to my specs. If this is good, it’s good and I’ll accept it.

Jason

  • Have you skim cut your waste board?
  • Do you use your waste board as Z-reference?

it’s not a great answer, but …

I ALWAYS cut into my waste boards… it’s a WASTE board. So what if you damage it? I usually have my CAM program run the bit 1mm too deep on the final pass. My wasteboard is a mess, but it does not really effect my carves.

I don’t buy them from Inventables; I get them at Home Depot. They have 2ft x 4ft x 1/2in thick particle board. I get two of them and cut them down on a table-saw to fit my X-carve. I carve at least once a week and the wastebords last about a year.

You have to drill and counter-bore to get the bolts to hold it down, but that’s not a problem because I have an x-carve!. Once it’s installed, I usually just use a standard drill to put holes wherever I want for my “clamps”. The bolt goes through my “clamps” and the wasteboard where it connects to a flanged “threaded insert,” (https://www.mcmaster.com/tee-nuts - I think I use P/N 94884A101, but check your thread size!). The Tee-nuts NEVER pull out and are reusable forever!

Probably not the answer you were looking for, but I’ve learned how to do everything with my x-carve the cheap way…

This is true, not arguing that one :slight_smile:

But when one is trying to chase down discrepancies or improve end-result presicion tuning the machine is required. And improving the reference system aka waste board surface.

If one have a “wavy” waste board and a material on top that isnt 100% uniform in thickness - and set work zero on the top of that… the depth relative to the material will be inconsistent :slight_smile:

If I am to carve through 1/2" material I “zero” off the waste board, then jog the tool up 1/2" + a smidge more, say 1/16" and confirm Home Position/work zero. In my design I set total depth = 1/2" + 1/16"
With a skim cut waste board my carve will now be consistent and precise :slight_smile:

Thanks guys for the great answers. I’m not worried about the waste board as much as I’m wondering if this is normal specs for the precision of the xcarve. I’m wondering should I be more worried about trying to dial it in more OR should I just be happy with this and work around it when milling precision pieces.

I know it’s very very minor offsets but wanted to ask others opinions.

The stated precision of a tuned and tight Xcarve is about 0.08-0.14mm :slight_smile:
(Edited to 0.08-…! :slight_smile: )

@Haldor,
I 100% agree with you, but … if some future x-carver who’s considering a purchase reads this, I DON’T want him to think: “wow, so I gotta spend 30 minutes ‘leveling-up’ before I can make a 5-minute cut?”

Na, just cut the waste-board, bro!!! it’s not ruined, just not “pretty” – besides, “Scars” are just “tattoos” with better stories! LOL

That’s my logic, anyway.

Really??? no way is the it that far off… I’ve carved gears (metric module 3) and sprockets (that run REAL #40 “industrial” chains)… I commonly use the “tab A into slot B” method of building “3D” things and I feel like I am NEVER “off” by more than a few 100th of a mm (.03 or so, maybe), but it seem DEAD ON working with wood… maybe 0.08mm, but certainly not 0.8mm - I could see that error with my 50-year old eyes!! LOL!

I even once made a "cycloidal’ gear that WORKED!! (https://en.wikipedia.org/wiki/Cycloidal_drive#/media/File:Cycloidal_drive.gif)

maybe, I’m crazy…

Keep the bit sharp, my friend!

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I’m pretty sure that Haldor meant .08mm
I know that mine is within .005" throughout.
Very impressive for a hobby machine.
But then I replaced my bed with ATP-5 aluminum fixture plate and don’t have to worry about humidity.

Indeed I was, thanks :slight_smile: (Prior post edited)