Please allow me to add some clarity here which may help in addressing some of your questions.
I chose the 30mm OD saw for a reason. It has an 8mm ID. 8mm is within a few thou. of 5/16" (.3125").
The next larger saw, 40mm, has an ID of 10mm or .3937". Slightly bigger than 3/8" (.375").
Going that route, you're into a totally different mandrel of greater overall size.
Would that mandrel come with a 1/4" shank? I don't know, I haven't found one.
Now let's talk mtrl. wall thickness that can be cut.
For those that don't know, I build a boat-load of Predator shafts every week.
This means that I part-off a lot of rings, either from tubing or billets.
All I really needed was a saw that would get through approx. .190" wall thickness.
I soon realized though that with a little extra machining of the mandrel, my 30mm saw
would now cut through a wall-thickness of .30".
Long story short, that's about .0125 shy of cutting through std. 1.375x.75" tubing.
This presents two obvious choices.
Either take a .020" pass on your big tubing before parting or reduce the head diameter
of the mandrel by a similar amount.
Look, you guys can buy the saws at the same price that I have to pay.
I'm at the mercy of these sellers just like you would be.
This is the same seller that Brent showed you. Here's the saw you want:
http://www.ebay.com/itm/320727579166?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
I don't want to make money by just flipping a ready-made product, then marking it up.
That's not fair to you guys and that's not how I'm geared.
I make my money doing machine work, I want to earn it.
So, I'll continue to provide custom-made mandrels and you're welcome/encouraged to get
the saw(s) bought.
If saws become available to me at a decent price, I'll certainly let you know.
Even though we've hit this minor hurdle in supply, I don't regret for one minute having
designed this tool. The damn thing is the nuts.
I'll keep looking for improvements to make on it and I greatly appreciate your comments
and suggestions. There's about 200 of these units out there and I'm honored by the names
of the CMs who have purchased these. I'm also honored that I've been allowed to make a
contribution to our craft.
Well, there were about 200 but there's now one less since Beau's mishap.