What is B.D.M.S.

This Forum is dedicated to the Hobbyist I.C. (Internal Combustion) Engine Community.

Moderators: Harold_V, JackF

Post Reply
Posts: 58
Joined: Wed Apr 16, 2003 6:19 pm

What is B.D.M.S.

Post by solek » Fri Dec 02, 2005 11:30 pm

Been out buying kits, and have a problem. Bought a Alyn Foundry (England vendor) hot tube Robinson kit. The problem is they list B.D.M.S. material to make the none casting parts. What is use in the USA to replace this material? Alyn Foundry does not reply to my emails.


B.D.M.S. is:

Post by jutz » Sat Dec 03, 2005 1:33 am

Basic Dimension Mild Steel.
Generally, you can substitute cold rolled steel for most BDMS. If there will be a lot of material removed, cold rolled might warp (especially if more is removed from one side than the other) so it's good to use oversize hot rolled and be prepared to remove a bit of extra material. As far as alloy, pretty much any low or medium carbon steel should work but it depends a bit on the part.

Posts: 8
Joined: Sun Nov 27, 2005 12:08 pm
Location: Sometimes Ireland

Post by deverett » Thu Dec 15, 2005 2:44 pm

BDMS = Bright Drawn Mild Steel. In old parlance this was called EN1A, a low carbon steel.

BDMS bar stock when machined will probably warp, especially if machined more on one side than the other, as the drawing stresses are released.

BDMS can be normalised to release the stresses before machining by heating to red heat and allowing to cool slowly. Once normalised, it can be machined without any problems.


Post Reply