I saw someone randomly mention doing that in a youtube video, I’m curious how it works and if it’s really a viable way to quickly switch out bits without having to re-zero. Seems kinda sketchy but I’m not sure lol.
I would worry about metal ones being off-balance and damaging the flutes.
The actual thing for this are plastic depth ring collars such as are sold by @TDA 's company:
(and presumably other places)
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I tried that…It did not do well. There was a discernable depth difference. Yes, it was a few thousands. I kept missing the bottom of the cut as well as scratching my spoilboard. Many of my cuts need perfect cuts so a few thousands makes a big problem for me.
On wood, it might not make a difference. Another thing on a drill stop, your bit is no longer balanced. Bearing wear could result.
Good Luck
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On industrial cnc machines with automatic tool changers they have a jig to set every tool the same stickout. They still have to zero but after that initial zero all the bits have the same length in the act bit holder. Those fixtures are much more substantial than collar stops.
i don’t understand why these items would be of any use on a cnc machine. After having designed the Z-zero the Shapeoko after every tool change goes and adjusts the cut z-zero to the project Z-zero. That is extremely useful. The CNC I had before -inventables- did not have that, for this machine always the cut z-zero had to be set after a tool change.
Otherwise the items you showed here appear pretty even, thus balanced, you sould use always the same size of screws and always both, the router machines run a pretty high speed and also have some decent power.
I rather recommend not to use any modifications to the high speed rotating spindles.
One might just admit to the reality of cutting with a CNC router; Z-zero is a required operation after every bit change.
Its just part of the process, and is no less important than spinning the bit.
Usual preface, I’m with PreciseBits so while I try to only post general information take everything I say with the understanding that I have a bias.
In general I wouldn’t recommend this. Of the few drill stops I’ve actually seen with a listed max RPM it’s pretty low in the router/spindle world. I think this is mostly due to being close to impossible to actually get these properly balanced (by spindle standards). In the case of single set screw versions you have a hole that is loose enough to fit around the flutes/shank. You are then moving the stop off center by tightening the screw to push one side of it into the bit. In the case of a double set you are now having to balance the midpoint yourself.
In “ideal” cases my worry would be earlier failure from the extra load to the bearings of the router/spindle. Although, that obviously depends on the bearings in question. In bad cases though you might run into a lot of vibration or catastrophic failure. We’ve actually seen catastrophic failure once with these. But I have no idea what the total in use is at these kinds of RPMs.
I won’t go to much into depth rings due to previously listed bias, other than this. They are spec’ed for high speeds and if they hit something they are plastic, typically reducing the overall fallout.
A couple things in general for stops/depth rings. They all have a tip to ring/stop tolerance (manufacturer set or otherwise). If that tolerance is outside your range they are worthless for your zero. Additionally, in some cases they are not recommend as you need the absolute minimum stickout possible or you are trying to limit skew runout. On the other side, they are removing or reducing a variable, and if set correctly, making sure that you are inserting the minimum/recommended shank length into the collet.
Hope that’s useful. Let me know if there’s something I can help with.
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