Chain Plates

[Storm]

I am in the process of changing out my stainless steel chain plates and am considering C655 silicon bronze. I am thinking of buying mill C655 bar and drilling holes and polishing to make my chain plates. I would be using either silicon bronze nuts and bolts or 316 ss.

One thing that concerns me is the source of the silicon bronze- some Asian sources may be questionable as to quality and if it is truly C655 specifications.

Please comment and advise if this is a good idea.
Regards

[Brion Toss]

Hello,
You are right, some Asian metals are not top-drawer. On the other hand, some are, But unless you know someone that you trust, who in turn knows and trusts others, and so on down the line, it is a crapshoot. But why buy Asian at all? Cost? If so, for whatever reason, your chances of getting good stuff are much better in this country. Think of it as paying a premium for quality.
Fair leads,
Brion Toss

[Storm]

Brion,
Thanks for reply. I would rather buy US made silicon bronze, but cannot find it. I have found some made in Germany, which I would expect to be of good quality. If I purchase, I will request mill data sheets to confirm quality.

This brings up some more questions. I was thinking of replacing my 316 Stainless chain plates with C655 Silicon Bronze. The Tensil and yield strengths, as well as hardness look to be nearly equal. Therefore I was thinking of making the silicon bronze chain plates the same size as my currently installed 316 stainless. Yet when I spoke with a rigger and a chain plate fabricator, they suggest making the silicon bronze chain plate bigger to account for elongation the material exhibits under stress. Could you comment on this?

Also, I am considering using Grade 5 Titanium, yet most of this material is made and and fabricated in China. I was concerned about the potential quality of the Titanium chain plate, but some articles about Titanium chain plates say this should not be a concern, as the material and fabrication are of good quality in China, as China supplies most of the Titanium material on the world markets. Please comment.

Regards

[Brion Toss]

Hi again,
Check Skene's and you'll see that Silicon bronze and stainless chainplates are properly done with the same scantlings; Bronze is more ductile, but the offset in the direction of the load, plus metal thickness and width, compensate. Not ever a problem, as the rigger should know...
You might see if Port Townsend Foundry can supply you with the chainplates you need.
As for titanium, I have had mixed experiences with Chinese metal. It is all about the supplier.
Fair leads,
Brion Toss

[Kinsa]

Hi,
If you haven´t already solved your problem this may help. I also changed my chainplates from stainless, but to nickel aluminium bronze. Supplier is a UK company whose main customers are the aerospace industry ( http://www.cnalloys.co.uk/). I didn´t think to check the source of the raw material. Finding the appropriate bolts was a problem, as the existing holes in the bulkheads are metric, but that has now been solved too.
Regards,
Bill Attwood

[Turimees]

I was about to replace the chainplates on my S&S 34 with another set made of 316 stainless, but reading your post and the subsequent string has stayed my hand. What argues for changing from stainless — is it the shortcomings of 316 in this application or the advantages of other alloys?

Regards,
Jan Waldin

[Storm]

Originally Posted by Turimees

I was about to replace the chainplates on my S&S 34 with another set made of 316 stainless, but reading your post and the subsequent string has stayed my hand. What argues for changing from stainless — is it the shortcomings of 316 in this application or the advantages of other alloys?

Regards,
Jan Waldin

The main reason I was considering another material besides 316 stainless is to get away from the stress corrosion cracking problem. I am located in Hawaii and the salt air and tropical heat is a problem for stainless. I was considering either silicon bronze or titanium.

[Douglas]

Ahoy Storm ,,, the last Silicon Bronze plate stock , that I purchased was from Alaskan Copper and Brass : http://www.alascop.com/pdf/brbr/silicon_comm_sheet.pdf ,,,,,, they shipped that small order to me on Langkawi Island , Malaysia . The shipping cost just about the same as the metal , itself .

Since there is such a heavy presents of US Military in Hawaii ,,, you might even find some silicon bronze supply, there .

[Storm]

Originally Posted by Douglas

Ahoy Storm ,,, the last Silicon Bronze plate stock , that I purchased was from Alaskan Copper and Brass : http://www.alascop.com/pdf/brbr/silicon_comm_sheet.pdf ,,,,,, they shipped that small order to me on Langkawi Island , Malaysia . The shipping cost just about the same as the metal , itself .

Since there is such a heavy presents of US Military in Hawaii ,,, you might even find some silicon bronze supply, there .

Douglas,
Thanks for reply. I am in contact with Alaskan Copper and Brass. Their fabrication shop can water jet cut from silicon bronze plate the size I need for my chain plates. This is great as I could not find silicon bronze flat bar that would meet my dimensions and I did not want to buy oversized bar and then have to mill or cut it down to size. Bronze plate is available in a lot morte thicknesses as compared to flat bar.
Regards