While browsing the user manual for my yet-to-be-built OF Woodworker, I read that OF actually suggests building up the spoilboard to 2.5 inches or more, to 'reduce the moment force' on the router, z axis bracket, etc. - in other words, shorten the "lever" formed by an advancing bit, the edge of the material being cut, and the carriage. I had not previously considered these force vectors...am I correct that one implication is that placing the router in the lowest bracket position and using as short a bit as possible results in a higher safe/effective/possible ipm than having the router mounted higher with a longer bit? I'm not saying I'm old, but my last physics class was the semester after 'Zac got bonked on the head with that apple...
Sort of right… the ideal position would be the center (or upper, IMO) position to reduce the lever forces against the gantry. However, this thing is built so beefy, this is more a theoretical conversation because, honestly, the forces of the router cutting are a miniscule fraction of what it would take to flex the assembly. (Hope that makes sense, it does in my head )
It’s always preferable to have the cutter as short as possible with the shank fully chucked into the collet. Whatever position you have the Z assembly placed, it should be with respect to a good operating reach for the bit & workpiece.
Yes Bill is right.
Basically, just don’t use a 3" endmill and only cut with the last 1/4".
The actual tool WILL or could flex (bend) rather than the actual machine.
We are talking about a little 2000$ hobbyist machine here.
Just worry about using an appropriate length tool with a conservative cut speed.
If you happen to notice that the machine or tool are flexing, it’s because you are doing something wrong… basically trying to cut too fast!!
Thanks for replies. Regarding flex and cutting too fast, that is actually the opposite of what led me to consider this issue…as I model various items I plan to cut once my machine arrives (using Vcarve Pro), I keep running into crazy fast IPMs in order to meet the recommended chip loads for typical end mills to avoid excessive heat build up.
About feeds and speeds.
Milling steel and aluminum is one thing… the feeds/speeds, depth/stepover must be perfect. Heat+/-, tool wear, material finish etc etc
With a 200k mill with a 10hp spindle and 100$+ endmills, everything is calculated to the “T” +/- 0.0001” at times.
As opposed to milling wood, with a 2000$ machine and a handheld router as a spindle (Home Depot) and 20$ endmills from Amazon
Your margine of error for your calculated feeds, with all these factors considered, leaves you a very LARGE window of play.
Wood is VERY forgiving!! Don’t worry about the heat.
Yes Vcarve is quite amazing, , and even though you specified a stepover of 0.1 for your 0.25” endmill… at 150 ipm somehow with certain types of operations, Vcarve will jump around and start doing full slotting at times. It really does not sound good when it does that.
So, While you’re sitting there in awe!! watching the machine do it’s amazing little dance, carving out what you designed/imagined over the past few weeks… the bit plunges down and starts making a new slot full width!! You’re gonna jump up in panic. Not to sure what to do.!!! . but before you realize it, everything just continues going normal… nice and easy. Lolllll
Basically what I’m getting to is, rule of thumb. Start with these safe settings, and you can adjust afterwards.
Depth should not be more than the diameter.
Stepover should be a bit less than 50% of diameter.
As for speeds, 100-150 ipm +/-
Plunge at 50% of that.
Wood is very forgiving, but still requires a little practice… I admit the speeds I mentioned above, are a little aggressive sometimes.
Trial and error, don’t worry about the heat, and enjoy.
Your imagination is your limit
Feel free to message me, and sorry this was so long.
Thanks, much appreciated.
Thanks for a reassuring post for somebody that is new to this and worried about burning up bits and obsessed about finding just the right router speed and cut rate.