Strong 0-80??
Strong 0-80??
(OP)
Hi all
I am currently using 0-80 3/16" stainless steel button head screws in an application to hold an inconel plate onto a stainless steel material. However I am finding that this type of screw yields when loads are applied to the assembly. These loads include axial forces and moments whose values I do not know (The moment on these screws could be anything up to 3Nm). What I really need is a stronger screw with the same physical attributes. I have looked into different types of steel but I am finding it difficult to find stronger materials in this size of screw. I am open to having the screws custom-made too. Any tips
Thanks
MF
I am currently using 0-80 3/16" stainless steel button head screws in an application to hold an inconel plate onto a stainless steel material. However I am finding that this type of screw yields when loads are applied to the assembly. These loads include axial forces and moments whose values I do not know (The moment on these screws could be anything up to 3Nm). What I really need is a stronger screw with the same physical attributes. I have looked into different types of steel but I am finding it difficult to find stronger materials in this size of screw. I am open to having the screws custom-made too. Any tips
Thanks
MF





RE: Strong 0-80??
If you don't mind going with a regular socket head instead of a button, you could try:
http://www.spstech.com/unbrako/htm/unbrako-1-21.html
(these are Unbrako - I would trust them)
The following site lists some as being alloy steel - I am guessing 12.9 - if so , thats as good as you'll get. But you have to be careful if they come from off-shore.
http://www.microfasteners.com/catalog/products/SSCSBA.cfm
RE: Strong 0-80??
RE: Strong 0-80??
RE: Strong 0-80??
RE: Strong 0-80??
I somehow get the impression the screws you are looking for are for medical (prosthesis) applications. In that case, alloy steel screws are out of the question , and higher strength 4XX stainless steels are not really stainless in the human body. The best material would be Inconel, and since Inconel 718 is a commonly used material in aircraft fasteners, you may even find what you're looking for at an aerospace fastener distribution house. The '0-80 3/16'is not a familiar size with me, but standard aero screws for nearest fit would be 10-32 UNF (.190 diam. 32 tpi)
Try www.fairchildfasteners.com
RE: Strong 0-80??
FYI, nickel is considered to have human compatibility problems, hence the use of titanium and low Ni/high N stainless steels vs. nickel-based alloys like Inconel for implants, bone screws, etc. More information can be obtained from standards such as ASTM F 543 and its references (F 1472, F1295, F1314, F1586, etc.).
RE: Strong 0-80??
RE: Strong 0-80??
Metalguy
I have looked into getting 17-4 stainless steel 080 custom made but I cannot find anybody willing to make anything of this size. My machine shop does not have the capabilities to make something this small.
Yates
I have checked out Inconel screws but again I can not find anyone who could make something this size. 0-80 screws have a diameter of 0.06" approx and have 80 threads per inch.
EnglishMuffin
I am restricted with the diameter and height of the head of the screw. I have strain gauges on either side of these screws. At the moment, button heads seem to be the most suitable head I can find (small diameter = 0.11" and low head height = 0.04"). I am a little flexible with head height (+ 0.015") but can not spare much more room with the diameter.
I am also restricted by the diameter of the screw itself. I can't go any bigger.
Theres no room to add more screws either
The stainless steel screws I was using began to bend along the shaft of the screw during use. The heads didn't pop off.
Strength wise, the best 080 screw I could find was a 10.9 alloy steel with a black oxide coating.
FYI the instrument is not a permanent implant in the body. It comes in contact with the body for a short period of time and is enclosed (not completely) by stainless steel components.
I have contacted many companies who manufacture 'special' screws but many have shied away from making something this small with high strength and a high corrosion resistance.
Any further tips would be appreciated
Thanks
MF
RE: Strong 0-80??
I'm sure there are a number of model engineers out there who would love to make these screws for you - they do stuff like that all the time and a lot of them are superb retired professional machinists. Try contacting the editor of Home Shop Machinist :
http://www.usubscribe.com/order.cfm?tid=11291&plky=21025>SE=GOTO>KW=The+Home+Shop+Machinist
RE: Strong 0-80??
I have read your dilemma and teh comments with great interest. There is a company here in Kokomo that can help you I am sure. I am not affiliated with this company but do know of them and their work. They are very heavy into medical prosthesis and specialty screws. I have lost their web address but I can give you their snail mail and phone number.
He is a retired machinist that started his own business and has grown very rapidly.
WIS Sheet Sheet Metal
Attn Bill Summers, Prsident
1501 E Co Rd, 200 N
Kokomo, IN 46901
765-459-8804
Good Luck.
Bill P.
Bill P.
CSFT, Inc.