I thought a thread to collect some of the learnings as I went along and provide an opportunity for others to share their hard earned knowledge.
As my father used to tell me," Experience is the best teacher, but it is also the most expensive."
He would also say “knowledge comes through bloody doorways”
Two things I learned about securing a piece being cut out.
- Placing the tabs on the long grain of the cutout, makes it easy to remove the stub of the tab with a block plane.
- Removing tabs is a pain, so don’t use them. Since I have a drum sander, I size my stock thicker than the final thickness. In the cutout contour I don’t cut all the way through (leaving 0.05 to 0.1 inch). Then sand the back of the piece on the drum sand until it separates itself from the stock.
Two things I learned about depth of cut
- Knowing the depth of cut on your cutter, when designing the depth of your features helps make for quicker machining steps. I had a big pocket (part of an advanced vcarve) that I didn’t realize was not an integer multiple of the depth of cut. This lead to a full cycle of cutting a very very small depth. I don’t recall the exact numbers but I think the last pass was 0.005 inches. Height I chose was arbitrary, so I could have eliminated that last pass. (though I should think about surface finish…but even with that knowing your cut depth can help you be deliberate)
- Pushing a downcut bit too hard can pull it out of the chuck. I had decided to try the downcut bit from the starter pack, but this was after playing with how aggressive I could get with the #201. The depth of cut was changing dynamically as the downcut was pulled further and further out of the chuck.(until it fell out). Even did this with the chuck tightly set. Down cuts probably need to be run less agressively. Perhaps I need to explore doing a downcut for a shallow starter pass and then switch to an up cut. (stuff I am still figuring out)
Two things I learned about positioning stock
- If I have two projects I want to cut in a similar width board, I can cut one and then rotate the board 180 and then cut the other. This simplifies getting to the drum sander back sanding to release (see previous “two things I learned…”
- Having the code for the project extend past the range of cut for your CNC is a bad thing even if it is slightly over. I was working trying to make some door hangers for my office, and being the largest in the Y dimension I have cut, (and with an XL the shorter axis) I went over by maybe less than an inch. Loss of steps which shifted where everything thought it was.
My pretty fence now has a hook groove in it. I made it wide expecting to cut into it, I just forgot that everything on the front end, reduces space on the back end.
I started this thread, not only to document and share some of my learnings as a new Shapeoko user, but also to encourage folks to share what they have learned. I figured the “Two things I learned…” format would make it easy for folks to contribute.
I am happy to help folks learn from my mistakes (though I would prefer to learn from someone else’s )
Premise for this was two saying my father would tell me as I grew up.
“Knowledge comes through bloody doorways.”
“Experience is the best teacher, but also the most expensive.”
Tabs can also be easily removed using a flush cut router bit leaving a nice finish. I use a Amana 3/16" flush cut bit for removing tabs in 1/4" contours and it works great. I use a larger bit for tabs that are not in tight places.
When using F360 once you find the best cutting parameters for a given cutter and tool path in the material you are machining. Learn how to save and use tool path templates they can save you sooo much time it’s crazy. It saves you from having to set the feeds every time and you can have all the feeds from a proven setup saved. That way on the next job you bring in the template and select the new geometry for each path needed and delete any paths you don’t need.
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