That’s a great idea! I’ll definitely be using this method!
I noticed that the router mounting bolts affect Y-axis offset, but not x-axis offset.
After tramming with a shim, It was still slightly off in the y-axis. That led me to check the router mounting bolts. Sure enough, both screws were very tight, but as I played with them, the dials started to zero. There was a range of adjustment that only affected the Y-axis.
So my takeaway is to make sure your mounting bolts are near the same inch/lbs of tightness. If you need a molecule thicker shim, you may want to try this first.
My other takeaway from a few hours of tramming fun was that eyeballing with a square gets you 98+% of perfect in less than 2 min and I doubt anyone could notice the y-axis offset effects even without the shim. But it’s dead on now, so one less thing to blame.
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I evidently got lucky - finally got around to looking at the tramming of mine - this was as-installed, with no real attempt to tram at all - just tightened up the screws…
Both x and y directions yielded the same result - this thing is square enough for me!
I’ve got my X axis dialed in, but not my Y - where is the best place to add a shim?
I would suggest shimming just at the top of the Left side of the mount, between the router and mount with a very thin piece of paper, you can use the corner of a playing card but that may be to think. Kinda have to play with it a bit, but def top Left.
-Alex
Awesome, appreciate it!
Resurrecting this thread to share my tramming jig. The indicator is the only fancy part that could absolutely be replaced with another drill bit and some feeler gauges.
I was able to get <0.002 over a 9" swing in X and Y!
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I started using a fixture like “ConvenientWoodwork” posted with my friends dial indicator but because my spoil board is a couple layers thick there wasn’t room to rotate the arm past the X Axis beam. Then I realized I didn’t need a dial indicator. I can just use the Z probe to measure each side and compare the absolute value of the probe on each side.
I used a quarter inch rod in the router end and a quarter inch screw at the probe end. I rounded the end of the screw to help ensure a consistent point of contact. This worked out very well and avoids the need to purchase a dial indicator.
Another advantage of this method is that the Z probe averages out the height of any sawtooth pattern in the board which would be a problem if you probed one side on the high portion of the sawtooth and the other side on the low portion of the sawtooth.
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I like how you think! Much better than using an indicator or feelers.
I am hoping that I am dumb here. Here was my entire process.
- surfaced spoilboard
- moved router to middle of spoilboard front and back and left and right
- left and right tram was off by 0.000"
- front and back tram was off by 0.055"
- attempted to fix front and back tram made it worse
- fixed my mistake and trammed front and back using the manufacturer tramming screws
- got front and back tram fixed to 0.0035"
- noticed left and right tram is now off 0.007" now
- checked all my trams from middle of spoilboard front to back and came up with the numbers showed in the picture
Am i crazy, is this close enough, do I have to resurface before I can do any more adjustments. Stressing out over getting everything perfect that I haven’t really got to use the machine since it arrived 2 weeks ago. FYI my Y rails are backwards to allow for more clearance for enclosure that my wife says I need to make.
The numbers by themselves do not hold much meaning, it is the difference between them that I am concerned about
Included an image of my tram diy gauge in case that matters
I’m very much still learning and a bish-bash-bosh sort of person (I’m no engineer), so I haven’t trammed using the pins/gauges etc. But my thoughts/opinions are:
- being slight out in the tram can’t be a big issue unless you’re using large-diameter bits.
- the only significant diameter bit I have is for wasteboard surfacing; I think it’s a 1.25 or 1.5-inch flattening bit.
- I, therefore, used the wasteboard surfacing process to tram my CNC (I created a spiralling-out wasteboard flattening path using v carve). I had to shim the bottom of the zslider to get a wasteboard that, to my eyes and fingers, is perfectly smooth.
- once you have a smooth wasteboard, I would get cutting (I find that I can use extra kindling this time of year
)
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Unless you’re machining metal is go with “it’s good enough”. I’m willing to bet that any wood you use will change dimensions by more than that just from environmental conditions. Including your wasteboard.
It’s funny how we used to be good with the results we’d get using hand tools and sandpaper. Now that we have a machine with the capability of achieving measurably precise tolerances we chase them to 4 or 5 digits of precision
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Brian, having built a couple of wood CNC routers, I can tell you are pretty darn close. Unless you have some inlay projects, you will probably not notice. The work on the table will average things out for you. The weather may have a bigger influence than what you are seeing. Start making some chips until your projects start getting complex. When you start making joints check them for square and then start to revisit tramming. As long as the machine is making circles and squares accurately, I think you are good to go.
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Hey Jim, hey all,
but this is different! If you do something with a hand tool and sandpaper (or as I rather would, with a cabinet scraper), then you will never get the same result twice. You’re having a bad day and doing a little more crooked than yesterday where you were in love.
But if you buy a robot that does the work for you, then if it does something crooked, it will do it crooked in exactly the same way every day, every minute, and at some point you’ll hate him for it. And then of course you will make sure that it does not make crooked, but perfect.
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I make crooked things by hand every day, every minute. 
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Hey Brian,
what exactly is the unit with which you give these measurements? Is it thousands of an inch? If yes, the difference between 0.040″ and 0.060″ is 0.020″, that is 0.5 mm. Whether one would tolerate that depends on what standard you apply and your preference.
At the moment when you measured this, it seems that your jig shows that front numbers are higher than rear numbers, and left numbers lower than right numbers, which would show that Z Axis is slightly tilted backwards and slightly to the left. But for the difference between the values at different measuring positions, the different heights may be a result of play in your measurement setup or of the unevennes of your wasteboard, or differences in the height of the points were your machine’s feet are located.
What you are concerned about may not be a matter of trimming the perpendicularity of the Z Axis (“tramming the router”). Trimming this will mainly have effects only on which patterns appear when surfacing or on the accuracy of vertical walls in deep pockets that you mill.
I ask myself, if you are crazy about trimming Z perpendicularity up to the point of not having started to use your machine since two weeks, i.e. if you are at the step of checking the perpendicularity of the Z Axis in relation to the plane that is formed by X and Y, you already have to be sure that this plane, i.e. the mounting surface, is flat, wich means both coplanar and even. You can ensure the evenness with the surfacing process, but not the coplanarity and thus not the flatness.
Machine could be twisted
If you have twisting in your mounting surface, it is difficult to measure it this way, because the twist will twist the X Axis too. And then your router will tilt according to the twist when moving it from left to right.
It is important that before doing 1.) is to have 0.): Ensuring Coplanarity of the worksurface, or better said, at first coplanarity of the four machine’s feet. Coplanarity means that all four machine’s feet are on one plane, which means to avoid that one machine’s feet is higher than the others, or better said, that your tabletop is twisted.
Many people go crazy for adjusting the rectangularity (“squareness”) of the Onefinity CNC (rightly because the Onefinity CNC, as its main weakness, does not ensure the rectangularity by itself) but they forget the crucial importance of coplanarity of the mounting surface.
Also many people believe that irregularities in their wasteboard will be eliminated with surfacing the wasteboard with a surfacing bit. But this is not true. If your machine’s mounting surface is twisted, i.e. if one of the machine’s feet is higher than the others, then your wasteboard will remain twisted, and so will every workpiece’s surface be twisted after processing.
To ensure coplanarity, Tom @TMToronto mentioned the fishing line method here the other day, which is simple and very accurate. Other methods are winding sticks, water tube level and level (optical instrument).
I would ensure this as the first step before assembling the Onefinity CNC on a table. Especially if your table has no diagonals to prevent twisting. This would mean that the coplanarity of your worktop depends on the evenness of the floor and, even after tabletop trimming, the coplanarity will go down the drain if you move the table somewhere else.
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Hey Rex,
I find this is a candidate for the “As precise as possible, as simple as necessary” prize.
I like solutions like this.
(yes I know, I like totally expensive measurement tools, but in my heart I like this.)
I want to thank everyone for the help and encouragement to keep going. I have trammed it to within 0.003" which is basically lean on the table tolerances. Hint for everyone who doesn’t want to go down the rabbit hole - use a piece of paper to get close not a dial indicator, the numbers may seem bigger on the dial vs just “I am one piece of paper off” lol.
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level (optical instrument).
A rotary laser level would work well also.
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