The eBay 10EE taper attachment (TA) bed clamp (
link) is CNC machined from 7075 aluminum and sells for $295. The steel version (
link) sells for $365, machined from unknown allow "billet steel". (Shipping is apparently not included in the price.) I think that a much better option is the casting from
Martin Model and Pattern. It's cast from gray iron and is unfinished, that is, it needs to be machined and does not include the clamping bolt, etc. At last word, Gary Martin was selling these for $75 plus $12 flat-rate shipping:
I'm in as well. PP sent.
www.practicalmachinist.com
As to the aluminum or steel versions being too strong: Virtually every TA bed clamp that's shown up here in the last 20 years has been broken in the same manner and appear to have failed due to excessive force being applied to the clamping arm. This leads some to conclude that the clamp is too weak and a desire to make a more robust version.
I think that's the wrong conclusion. The design of the entire TA assembly, including the bed clamp, does not appear to have changed for at least 25 years, starting in 1944. I have no doubt that if the clamps were failing in normal use, Monarch would have redesigned them.
It's easy to see that if the operator over-travels the TA when the bed clamp and rod are in place, something will break. Either the rod will bend, the bed clamp break, the bracket on the bottom of the TA itself will break or worse. If the bed clamp is the strongest piece of hardware, something else will bend or break. It's my belief that Monarch intendeds the weak link to be bed bracket.
Gray cast iron has a tensile strength of 20 to 50 ksi, depending on the grade. The eBay aluminum bed clamp is made of 7075 aluminum, which has a tensile strength of about 80 ksi, that's actually greater than some steel alloys. So the eBay clamp IS stronger than original clamp and I don't think that's a good thing.