I initially bought a router (this router) for some door hinge mortising. Now I need to route a few 1"x1" channels in some MDF. The 1" x 1 1/4" bit I need has a 1/2" shaft, but the collet on my router is only 1/4". Here are my questions:
If I can, should I?
I'm guessing that your idea is to make a single pass with the router set to a depth of 1".
For your project, I would not recommend the single-pass approach in MDF, or any analogous material for that matter, even with a 1/2" shank router bit with spiral flutes designed to clear the shavings out of the dado.
Instead I heartily suggest making several passes at increasing depths, removing perhaps 1/4" of depth or less on each pass. For this, a 1/4" shank 1" diameter carbide bit would be adequate if you dropped the bit into the collet as deeply as functional, perhaps pulling it out a ways, if necessary, for the final pass.
Better yet, hog out the bulk of each of the channels in several passes with a 3/8" or 1/2" diameter router bit, then make a final pass at full depth with your (still super-sharp) 1" diameter router bit to obtain your precise width and depth.
Hope this helps.
FWIW: I'd skip the rectangular tubing and router approach. I'd use flat stock and cut wide kerfs that are 1" deep using a long strait-edge clamped in place and a skill saw with a heavy (thick) blade that will cut wide kerfs (e.g. 1/8" wide kerfs).
FWIW #2: Whether you use lengths of tubing or flat stock, your door will still be prone to warping, even if you embed lengths of metal stock in multiple orientations. To counteract the tendency to warp, you'd need to embed a rectangular metal frame. ... or don't embed anything: use lockset hardware similar to that which is used with French doors. That hardware will secure your door at the top and bottom, keeping it flat.
FWIW #2a: If you don't believe FWIW#2, prove it to yourself by gluing some bamboo skewers in the pattern of your choice to a sheet of heavy paper. Once dry, you'll find that the paper is quite flexible (warp-able) even without bending the bamboo skewers.
According to Fiasco Labs that router apparently doesn't have a 1/2" collet available for it, so this is kind of a non-starter.
But as a general answer, "palm routers" and "laminate trimmers" are small and good for hand-held work like edging and thin cuts, but aren't good at removing a large amount of material. It looks like your model doesn't have an adjustable speed, which is a good feature for using large bits. Larger bits means larger diameter, which means higher cutting edge linear speed for a given RPM. You want to run larger bits at a lower speed, to account for that.
As mike says, you don't want to do a 1" x 1" cut all at once. Take it slow. The suggestion to do several rough passes and then a single finish pass is a good one. If you have access to a circular saw, making several slightly shallow passes with that would also be an easy way to remove some of the material.
It depends on the size of the motor shaft, if it's large enough, Bosch will have provided a 1/2" collet as an available accessory.
In looking through the Bosch specs and accessories for the Bosch PR10E, they only show a 1/4" collet as being available which means the motor shaft size is too small to support 1/2"
At the speeds that these bits turn, having a large, well supported drive shaft is quite important.
