Baseplate surfacing lips

MR-1
1

I built this last year and got it “good enough” for winter and little projects but now im actually doing production stuff it needs to be correct. I had this issue on the baseplate that when running langmuirs surfacing program with .5 in 2 flute i have lips on every pass. Like my nod is out. Y - with finger nail hits lip. Y + is not hitting lip.

Tells me nod is tilted towards negative (facing doors) my card for head nod is punched negative .003 and .004. i missed the 4 last year and didnt put enough shims in. Corrected this the other day and with 7 shims on the top per the calculator and im still getting the same lip.

Whats not making sense is, how would shimming the top reduce nod tilt in the y negative? Would it not make it worse?

Update, i shimmed the bottom bearings on the spindle side, this reduced the lip. I am going to get feeler gauges from the hardware store and cut down what i need and hopefully that will fix it

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2

Sounds like you’re on the right track.

After adjusting the nod to get rid of any lip be sure to check your Z axis perpendicularity to X and Y. I found when I was adjusting my nod out I ended up getting some perpendicularity error showing up.

I had to back track and shim the carriage for my Z axis perpendicularity and also shim behind the spindle block to dial out the nod completely.

It was probably “close enough" for most of the work I put on this machine, but in the event I needed a really flat surface I wanted it to be dialed. I’ve held a few tenths parallel using a fly cutter to face parts, so it’s as good as I could expect for the cost of the machine.