where could I get an armboard custom made?

If it is made of wood and you have dimensions, both the overall size, and a diagram or template for the tonearm cut-out a decent cabinetmaker should be able to make one for you. If you don't know anybody that does high-quality or close tolerance woodworking, you're welcome to contact me if it's not a violation of any Audiogon forum policy.

Perhaps you can obtain a blank one here.The Thorens distributor for the US is WS Dist. LLC. They're located in Grand Rapids, Michigan. Ph# (616)885-9809 or email, Sales@WSdistributing.com
I found this link on the Thorens homepage. Hope it helps

thanks! I left a message with the distributor.

if you're curious, I contacted a seller of carbon fiber materials, which could machine one from carbon fiber for around $750. That would be cool, but mighty expensive.

James Campbell. Do a google search for solid birch plinths and "JEC" and you will find his contact information. He is great guy and does first rate work. He works with many different materials, including aluminum and slate.

This is certainly a very late response so it is I tended for owners of the td850 who think the michell vta adjuster is not compatible with the td 850 arm plate.....which it is. All you need to do is purchase a 5 mm headset spacer 1 and 1/8 in diameter and use it as a shim. Heck....go all out a buy a carbon fiber one for $10.00....or go basic aluminum for around 10.

Job complete and done inexpensively, too I might add.