Guy's thanks for taking the time.
Here's the why of what I'm doing.
I'm installing my bed and would like to do some deep/long reach routing to put a type of t slot into the bed. Then I'd like to face the bed off so its flat. This will be done once [hopefully] and shouldn't need to be done again. I've designed my mill so that when I'm doing machining, the parts will be loaded on a pallet of sorts and be removable. The pallet's would be ~4-6" thick. Rarely would I ever have to reach right down to the table surface, if ever. I've also left a bit of room for my expansion to a 5 axis system, which will eat up some of my vertical height as well.
The machine was build for making composite molds and bucks. All for large stuff like car parts, boat and airplane parts.. Anything else I can get to work [aluminum machining etc] is just a bonus.
Another approach I've been thinking about is to shim up my bed so that a standard 6" long tool would reach that deep. I can always remove the shim's later to regain the lost height. This would require shimming the table ~3".
For cutting things like alum plate or thinner parts I plan to use a table which I can install on top of the bed and level to it. This will keep my z axis extended as little as possible and hopefully allow me to do some alum milling as well as the wood and foam that the machine was originally intended for. I've got over 24" of Z travel so doing heavier cutting w/ that all the way extended down is going to probably cause chatter and deflection problems.. [I don't know yet as I've not tried this yet]
My spindle is a 18k 2.2hp w/ an ER25 and a max collet size of 5/8".
I have to admit that my largest weakness when it comes to all this stuff is tooling. I'm not familar with most of it or how it's applied. I've bought most of the book's I can find about this kind of stuff, but most of it assume's you know what or how these tools are used. I've got lots to learn in this area. I think sitting down and talking w/ a machinist for a couple hours would help me more than anything in this area.. [Geof, I do still plan to get out there
]
Knowing what type of arbor fits what type of shell mill or face mill etc..
I see lots of face mills for sale, but never w/ an arbor and it's a shot in the dark to just buy an arbor with the hopes that a shell or face mill will fit it..
What I'll likely end up doing is buying an extension for the end mill's I have. a Fly cutter might do the job for facing off the bed, but cutting the slot's for the t slots would probably need something smaller? BTW, I'm doing a built up t slot from MDF. I've got a 3/4" sheet which I'll route out 1.25"w x 3/8"d and then lay a 1/2" sheet over this and route out matching slots in it that are 5/8" wide, thru the 1/2 mdf. If that all makes sense.. I may change some of those dim's if I end up buying a proper t slot kit.. otherwise I'll just use my own design.. haven't decided yet..