I’m making a 4 tier cupcake holder. I’m planning on running 4 supports between each round recessed 1/4 inch into the lower and upper tier of each section My concern is centering the mortises on both sides of one round. My thought is to do the top side then flip the board bottom to top and corner off the top left after the flip. That way I index the machine off the same corner
1 Like
As long as your stock dimensions are consistent that should work for you. You will need a fixed referenced fence to ensure accurate milling after flipping the stock. Do not rezero your X/Y coordinates between cuts, just re-run the same file. Run some practice cuts on scrap wood first and dial it in before you use your good stock.
3 Likes
Several posts lately about problems with 2 sided machining. All the advise is to leave the X Y and Z set on side 1 alone and do not reset your zeros. Your material must be precisely measured and all the objects centered on side 1 and side 2. The consensus was to not rezero but simply use the original zeros set on side 1.
1 Like
I do this when I’m machining higher tolerance metal parts. I also touch off at least one other surface to double check.
There are several ways to introduce error when flipping.
Setting the new zero. How close can you get the new zero point? If you’re using a parallel fence along the left side (Y axis), your X & Z don’t change. Only the Y. I’m pretty confident I can eyeball a zero with a pin or tool to the edge of a part (If it’s cut smooth & square) within 0.001"
Stock size. If you are leaving the zero and flipping the part you are zeroing off a new corner. Your stock has to be pretty precise. In Opie’s (Kevin’s) videos he uses the machine to cut the stock to size in the first operation to eliminate this variable. (Or get it within that 0.001" tolerance).
There is a 3rd option that eliminates both of those variables… Flip it diagonally so the same “J” corner is still in the lower left corner.
This adds a little complexity to the design. You have to mirror and rotate the design if it’s not symmetrical. And the machine has to be calibrated so X & Y are both cutting the same size.
And the “J” corner has to be perfectly square. This works best if you trim the fences using the machine and the same zero you use for the job.
If the part/stock allows, you can also use dowels somewhere in the offal to index the part.
Dowels evenly spaced about the centerline eliminates any variables in stock size, picking up a new zero, and even machine calibration…
4 Likes
There’s a good video covering this technique here: https://www.youtube.com/watch?v=iHKD4E1muoo
1 Like
I fully expected this to link to a light burn tutorial 
Today I Learned what a “J” corner is 
Gonna toss that in sometime when talking to my real machinist friends so they know I’m cool 
2 Likes
This topic was automatically closed after 30 days. New replies are no longer allowed.