question regarding height of collets and bits...

[thekm]

quick question... I'm fabricating the part of the machine that holds the router and need to know how high to set it, but being my lazy self, haven't yet ordered bits, collets, and so forth. I'm using the Hitachi 12VC router (that seemed to be popular around here), so the question is, if you're using the same router, what the height of your setup from the bottom of the main router housing to the tip of your bit?...

...I'll be trying to make it so that it can be adjusted, but the info will certainly help (and more so if it becomes fixed).


(and thanks in advance to anyone with such info )

[nicanor76]

In other words: how far would the router hang below it's adapter/holder, right? Looking at some picts in the gallery they seem to vary alot. IMO some of the adapters/holder setup I've seen may interfere with works on deeper cuts, as the adapter/holder itself may start hitting the materials (of course it depends how it's cut and other factors). Of course not all people would want intricate deep 3d cuts so may not be an issue.

[thekm]

Originally Posted by nicanor76 In other words: how far would the router hang below it's adapter/holder, right?

not the adapter, what's under the router itself. To make it more clear, here's a quickie diagram...

[ger21]

I don't have a Hitachi, but I can tell you that bit's can extend anywhere from 1/2" to maybe 3-1/2" or 4" below the collet, not the bottom of the body. So just add the distance from the bottom of the body to the bottom of the collet to these numbers.

[CarveOne]

To add to what ger21 just posted, the router body position on the mounting brackets is most important when you need the full travel possible, and the longest bit length available, just to reach down into cavities of some object you are routing. Deep moulds for fiberglass lay-ups and castings come to mind. The router body position on the mount can cause chatter with long bit lengths if the router body is extended so far below the mounts that it is not well supported by the mounts. For most work I would keep the bottom of the router body at the lowest router mounting bracket and choose the shortest bit length needed to reach into the lowest parts of the cavity, Use the minimum z axis travel needed to do the cutting. Cutting bit chatter can make a mess of precision mold making, and craft projects.

CarveOne

[ger21]

Originally Posted by CarveOne Cutting bit chatter can make a mess of precision mold making, and craft projects. CarveOne

And to add to that, always use the shortest bit possible for the job, which will also help to reduce chatter.

[thekm]

...I fully agree on all points, from the "to play with deep cuts" to the "set the mounts as low as possible". I was just hoping to get someone's size as some kind of as-is measure of the dimension in the little diagram to set the details for the mount. The bit range from Ger is handy, I'll just throw in an inch for the collet adapter.

My machine is a steel build, so the assembly wont be adding too much around the router itself like many of the woodies do, I just need to set the mount height after I set my Z-axis today.

[ger21]

If you don't have the router yet, I'd wait to locate the mount until you have it.

[thekm]

Originally Posted by ger21 If you don't have the router yet, I'd wait to locate the mount until you have it.

yup, have the router, just haven't got around to getting the cutty bits yet.

[jeffmorris]

It's better to get the bits and measure them before building the rest of the CNC router. With the small bits, you want them to touch the table with the Z-Axis carriage moved down almost all the way.

[thekm]

Originally Posted by jeffmorris It's better to get the bits and measure them before building the rest of the CNC router. With the small bits, you want them to touch the table with the Z-Axis carriage moved down almost all the way.

with bits going from 1/2" to 3-1/2", there's enough play there to get something going for my mount. I was just after someone actual measurement of what's hanging under their router, because there's plenty of wiggle that will happen anyway with the bits themselves.

The extra details and advice is great, but getting this measurement from someone really would be handy.

[jeffmorris]

After building my CNC router following the plans from Solsylva, I found out when using long bits, there's not enough room for wood to be routed so I raised the machine about 3" so that I can use long bits but later, I found out that I raised the machine too high after trying to use short bits so I lowered the machine by 1-1/2". Please get the bits before building the rest of the machine or you'll have too much work trying to fix the problems. Long bits can be inserted all the way into the space above the collet but short bits should be inserted so that the top of the bit is about even with the top of the collet.