I’m having a hard time interpretting your spoilboard measurements and understanding exactly what each one represents, but assuming the oblong holes are accurately portraying what you’re seeing, it doesn’t seem to follow a pattern for the x/y axis.
Oblong holes are generally caused by differences in travel for the x/y axis, so it seems to me that it can only be one of a few possible factors. You’re losing range due to mis-calibration of the axis travel, losing steps due to friction or any possible other interference, or something somewhere is loose. variations in height on the material could result in exaggerated discrepancies too, causing some cuts to begin sooner or later in the z-travel.
I don’t really have a lot more to offer in terms of help, sorry, but I will say, please try doing a larger measurement over a longer distance for calibration, and also set up a job that moves to several points to drill holes, and repeat the job to see if it varies consistently or inconsistently (next set of holes on the same job have different discrepancies?)
Oh yeah no worries I will keep at it and see what I come up with
Basically in my measurment sheet
I set the z to 1 constant height above the spoilboard and then I moved it around the spoilboard in all those different points and measured with feeler gauges the height of the z to the spoilboard
then the measurements with the arrows is just saying the total difference from left to right or front to back on the machine
and yeah I will go back and try the calibration over a longer distance and see if that changes things I wish that there was a more accurate way of measuring that distance because you could be off .010" and never really know and the machine should be accurate just below that probably .005" if set up properly
yeah i can try the different hole patterns but I have noticed that when i need a hole pattern or letters all in a row they come out perfect its only circles that seem to give me the issue lol
Oh okay so those measurements are z variations? You probably need to resurface your spoilboard. Did it ever interrupt or have to resume in the middle of your surfacing process? I had that happen for me and the result was I never did get a perfectly level surface until I ran it all over again.
Make sure that after surfacing you don’t adjust your router position/tram at all, or it will throw things off, too.
Also, is it possible that you didn’t machine away a complete layer the first time? As in, some areas got machined away but others still have the factory surface… if so, it wasn’t done properly, you need to make sure you go deep enough to remove material from all of it, leaving no factory surface.
yeah I might to resurface the spoil board and see it that helps
So my spoilboard consists of 2 pieces of 3/4" mdf
the bottom sheet is bolted to the machine bed and the top it bolted to the bottom sheet
I noticed the other day that if you look on the edge where the 2 pieces meet you can see a little gap and actually push down on the top sheet and bring the 2 pieces together I would say a .005-.010 gap
I am not sure why on the edges it is doing this I have over 30 bolts bolting the top sheet to the bottom sheet
this might be happening because alot of the time I just screw my work pieces down directly to the spoil board with wood screws and the screws are long enough to go through the top sheet and into the bottom sheet maybe the screw when it goes in is trying to separate the 2 sheets
but I can see that gap when I dont have anything screwed down
here is a pic of my spoil board
My approach was to bolt the bottom sheet down, and glue a layer on top of that, allowing me to continuously shave it down whenever I need a fresh surface, while not worrying about hitting bolts. When it gets low enough I can just glue a new sheet on top and surface that. The glue layer also provides a much more reliable set of contact points (pretty much the entire surface) so nothing can pull away due to tension etc.
The gap you’re getting is interesting, and can probably be avoided with the glue method I mention. I also tend to not like screwing directly into the surface just because it can create zones/mounds where the MDF has been pulled up or bulged.
You definitely want to eliminate any variation in the spoil board’s height, that’s going to make things really difficult in the long run.
I think you found your problem. If you screw through the top spoil board into the bottom board you are going force some separation between the two boards. If you take the top board off and look at the bottom of it you will see where the screws pushed up the edges of the holes they made. I was doing the same thing before I noticed the problem it caused. You need to be very careful not to let you hold down screws go through the top spoil board.
I wound up with an aluminum t-slot base and strips of 3 inch wide 3/4 MDF bolted to the t-slots with recessed screws. Then I skimmed .03 off the top of the strips to be sure it was true to the Z axis.
That way I can use t-slot clamps instead of screwing the work down.
dang it lol yeah all true I might need to change the way that my spoilboard is attached
I actually designed a much better spoilboard for the machine but its almost 1000.00 bucks lol so I went with this one for now I will try that glue method and see what happens should be interesting trying to clamp the entire sheet down especially in the middle
I would like to install t-track in the spoilboard to give me better mounting options but once you do that you kinda limit yourself on the different setups that you can do on the machine imo
I really want to start using composite nails as my primary way of holding things down but the nail gun is almost 400 bucks kinda ridiculous imo
I have been using my brad nailer to hold items down and that seems to work well but you have to send a bunch of time taking them out of the work piece scrap or the spoilboard itself and it can become really time consuming.
really to fix all of these issues a vacuum table would be the best option for work piece holding I have been debating about building one the entire length of the table but it really needs to be made out of a plastic or aluminum so you can gasket off sections for your work pieces
we are taking big money in the material for the spoilboard not even including the vacuum pump that you will need which is 1.500 to 10,000 in of itself lol
I had never heard of composite nails, very interesting idea.
@DylanSquires
Hey man i had a long talk with Cory over at cnc router parts and he was saying that you should never ever calibrate the axis in Mach 3 the xml file that they provide is absolutely perfect for there machine and should never be changed
but what I did find was that my machine was out of tram about .030" I adjusted it and got it within .005" tram I am going to run some tests on Solid surface material and see if I can get the edges to align perfectly my last customer gave me a 98% out of 100% really cut me deep 
how did you detect that it was out by .03?
so basically I bent a 1/4" rod into a L shape and then put one end in the collet and then placed a large piece of glass on the machine then lowered the rod till it touched the glass and then sweeped the glass in the 20 inch diameter circle and found that my router was leaning back by .030"
Clever idea, Now I want to check mine.
oh yeah check it so much easier than buying and tramming gauge with dial indicators
but now my spoilboard is giving me issues I guess I am going to have to take the top piece off and glue it down
Looks like you’re getting it all figured out.
Here’s a great tramming technique: https://www.youtube.com/watch?v=DmuipSuDNAs
Interesting about the xml file, but I can’t help but wonder if anything varies within tolerance (motor, rack and pinion etc.) how the xml file can account for that… I’ll have to talk to Cory to try and find out more.
Did your Onsrud upcut tools arrive? My package showed up yesterday. Just like the first 5 I ordered.
Yeah i got them yesterday and they look pretty good
lol its amazing to see the way tools where made back in the day it almost looks like a 5th grader went crazy on a bench grinder.
I haven’t cut anything with them yet
@AllenMassey
Hey allen did you need a number to a Onsrud rep for future tools?
I have never had a rep for tools before. Can he get me deals?
He can’t get you deals but he is a wealth of information and works for Onsrud and will help you out with what ever you need tool related
I always call my rep before I make a purchase on tools because he has 25+ years of first hand experience with end mill tooling in all industries and materials
His name is Tom Cornwell and his number is 316-305-3062 tell him Evann from Workin Woods sent you he will know who I am
Also tell him you need the production and specialty tool catalogs from Onsrud
