Newbie-Tramming from front to back

Hello all,

I’m a first time purchaser of a CNC (but been woodworking for 15 years). I finished putting my Longmill together (30x30), and it was pretty straight forward. I used the 3 4 5 method to check the squareness of x and y and i’m within 1/32 over 20" (hypotenuse). I also trammed left to right by adjusting the router mount and I’m pretty dead on when using the ‘draw’ a circle with a bolt at the end of the stick just above the surface. However, I need to adjust front to back and for the life of me, short of trying to shim the router, I can’t figure it out. Also, because I’m dead on left to right, I’d really prefer not to adjust the router mount again as I’m afraid to mess up my left right tram.

Can anybody tell me how to do this?

Thank you very much

Greetings to @acutabove, welcome to this little place of help and refuge.

First question is have you surfaced your waste board with the machine?

Kinda sounds like the machine is ok but the spoil board is not, just my thoughts.

Hi Bill,

thanks for your reply. I did not surfaced my waste board yet: I just measured off the base board. I’ll go ahead and surface my waste board. I’m assuming that I see those ‘ridges’ from the surfacing bit, then I have tramming issues?


@ACutAbove I will second Bill’s welcome, Jason. This is a very helpful place, so feel free to ask questions and post pics of your projects.

Back to tramming; if your Mill is out front to back, the only way to fix it is to shim it. I’m with Bill, though, before doing that, surface your spoilboard. You may well find that fixes your issue. Let us know how you make out.

Thank you, I’ll do it this tomorrow and report back.

Aloha from Hawaii,


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That brings me to another question. Which should you do first, tram the mill or surface the spoilboard. I’m getting ready to install a new spoilboard and I want to know the correct sequence of how to do this.

@gtrboy77 Surface the spoilboard first.