I am trying to cut a ring box out of walnut. I had made two previous versions and everything worked well but I needed to make some changes to the holes for the barrel hinges. The problem is twice the machine did not retract high enough and cut across the material.
I have never had this happen before. I can only speculate the machine lost Z steps. I did do a lubrication of the top bearings and lubricated the rails of my HDZ. I will jog up and down to see if that helps.
Please take a look at my file. In the first one I had a retract height of .15" and changed it to .2" for the second one. I do not see anything unusual about the file and have cut this same file with some modifications twice before.
I have just posted the same thing in the BETA thread, but it looks to be the same issue as mine, where the Z - Zero is running about 5mm too low then what is being programmed. I have the same setup as @gdon_2003.
I put this project aside and last night I started again. Dooooooh! the bit was loose in the collet so the only problem was a loose nut on the keyboard. So I was telling CC the bit was a #251 but I was using a 4" OAL bit with a 1.5" cutting depth. The material was .95" so the bit I used is a 1/4" down cut but just longer. When I put that bit in the router I have to push it all the way up and back down about a 1/4" or it will not rotate round. I guess the extra tool length caused vibration and made the collet come loose and the bit slip down. So on the restart every time the bit came to the front I would check the tightnes and it never came loose again.
Doooooooooooooooooooh!!! So the Shapeoko and CC and CM were not the problem I was.
So I kept doing a 0.002" offset until I got the holes just right. Here is a few shots of the ring box unfinished and initial sanding done. I rounded over the back top and bottom of the two halves so the barrel hinges open properly.
Now on to sanding and finishing. The first one I made I put the bride’s name on top. I did not like the way the epoxy filled it. I think I will seal it with shellac and then paint it white or red. The white would match the box but the red is more heartsy.
The box top engraving was done with a 15 degree vee bit. I let the line run over the sides of the box.
The barrel hinges fit well but when final assembly is done I will put some Titebond Medium CA glue in there for belts and suspenders.
