Both have their place, and are useful.

The 1" arbor can be quite expensive. Once you have it though, decent
used 1" hole cutters are dirt cheap at many used tool dealers, often
less than much smaller end mills cost new. The 7/8" hole cutter sizes
are MUCH harder to find.

The end mill holders are fairly inexpensive, and you only need a few
since most cutters have standard sized shanks. Still, a few extra are
nice so you don't have to keep changing the cutters in the holders as
often. It's usually faster to change out a whole holder than change out
a cutter.

Dan Mitchell
==========

Bob Engelhardt wrote:

I have an bench-top Atlas horizontal mill without any tooling. It only
has a 7/8" arbor and there are very few 7/8 cutters (on eBay). I see 2
alternatives: buy (?) or make a 1" arbor and buy cutters for it, or buy
end-mill holder(s) and end mills.

I'm leaning toward the end-mill approach for these reasons:
- the 1" arbor is going to be expensive to buy or over my ability to
make
- you can do more things with end mills (e.g., dove tails and slots)
- there are more end mills available than arbor cutters
- end mill cutters are easier to change than horizontal arbor cutters

The only thing that I can think of that I'd be giving up is the greater
rigidity of the horizontal arbor.

Am I missing anything?

Thanks,
Bob