ER20 Toolholder...not collet

So I have just replaced my Porter Cable router head with a Chinese water cooled spindle on my router table. It takes an ER20 collet.

I am having a problem and am wondering if others have the same issue that I have. When using a collet, you have to set/verify tool length after each tool change. I would like an ER20 toolholder, like a rigid tooling holder so that my tool offsets do not change when I make tool changes.

What I want seems very simple and readily available for every other machine tool taper (r8, CAT40) excepth the ER series. I am asking for a show of hands for who would find an ER20 "toolholder" useful and would want a set of the common fractional sizes.

Or maybe this already exists and I have not found it...

Thanks,
Paul

I should probably clarify that a toolholder makes no sense unless your spindle taper is ER20 like mine and anyone else who is using the chinese spindles. So that is probably why I can't find them out their already.

Yes, that's exactly right. ER collets do not have a way to preset the tool length. I have the same problem with my r8 mill collets... BUT if I want to preset the tool length I use a r8 toolholder which typically uses a set screw to engage the Weldon flat on the tool. I have a dozen r8 "tool holders" with known tool heights so tool changes are easier. Now a lot of people with homemade CNC routers are using the Chinese VFD driven spindles or some other brand of router head that does not have a toolholder option available, only a collet setup.

A toolholder differs from a collet in that it rigidly holds the tool between tool changes.

So...If there was a toolholder system available for your particular spindle (ER20 in this case) that allowed you to preset the tool length, would it be as valuable to you in practice as the r8 toolholders are to machinists?

Sorry if my question was confusing.
Paul

Just something to keep in mind: weldon flat tools in a setscrew endmill holder are not designed for the high speeds of that spindle. They are notorious for poor runout and balance which can not only cause chatter but damage the spindle bearings. This would be exaggerated if you screw a toolholder onto your spindle nose--increasing effective length. You won't see a high speed machining video on youtube with a setscrew endmill holder for a reason. Many er collet chucks have a screw to use as a tool stop for repeatable tool length changes. I don't know if you could incorporate a screw and jam nut into your spindle, or if that would even suit your needs. Is your spindle hollow (a thru hole)? You might look at the taig er16 to 3/4-16 adapters. It is a stubby collet holder that screws onto the 3/4-16 threaded spindle. If you made something like that to thread onto the m25 thread of your spindle you could leave the tools and collet installed into each of these collet chucks. Or with a hollow spindle you could use the er taper with a drawbar to make something like miniature nmtb toolholder chucks. Whatever you do, runout is a huge deal at higher speeds and smaller cutters--it will take precision to make it cut as well as it does now.

What about glueing a precision made metal ring to each tool, so that the ring touch the bottom of the collet when the tool is inserted?

I'm not sure if it would be repeatable enough... if anyone tries it, please report on the results!

BigJohnT wrote:

The OP would be money ahead to forget trying to make a CAT20 tool holder out of an ER20 spindle and use that time to just make a touch off gauge.

John

Yes exactly, my old RF45 used the Tormach toolholders and they used er20 collets so I am familiar with this. I would think a metal ring epoxied carefully onto the tool to sorta get you in the ballpark and then as John said an automated tool touch off plate or sensor setup would get you about as far as you are gonna go with it. Some of the larger Chinese spindles use quick change Tooling holder so that would be the next step up. Lotsa CNC routers out there with toolchangers. Another option is I Thought I saw someone had a quick change collet system for Porter Cable style routers now and they make some pretty powerful large body Porter cable routers we used in the pro Woodshop and they are pretty smooth and relatively quiet. Just another option ...peace

Pete