thread rolling waspaloy?

[dmatt]

i have a customer, who is getting ready to thread roll a 5/16-24 thread x about 1/2" long, in aged waspaloy. (35 r/c). the parts are in the 1000's (qty). i have found the tools, however the mfr's are not much help with any foresight (semi-understandable). i need to now - what oil or coolant would be best? and how many parts he can expect with each set of rollers (ish)? and any other pointers anyone might have. thank you in advance for any input.

[wildwestpat]

Hi dmatt

That material is difficult to machine even with carbide or ceramic inserts. Due to the elasticity of the material rolling will be difficult. Consider anealing the material first and then heat treating to give the correct temper for the finished article. Just be aware that this material is frequently found in aggressive heat and chemical environments for parts subject to a lot of mechanical stress so there may be legal conditions that are attached should parts modified fail resulting in a safety issue. Have you tried contacting tool makers with your problem. The makers of these specialist metals as not going to be very helpful as they also offer machining services and might also be ducking any legal implications in offering advice that leads to deffective parts.

Regards - Pat

[dmatt]

pat

thank you for your advice. you are right, that is the exact problems we are running into. mfr's are not much help, and it has to be rolled in the aged state for aerospace stress reasons.

Originally Posted by wildwestpat Hi dmatt That material is difficult to machine even with carbide or ceramic inserts. Due to the elasticity of the material rolling will be difficult. Consider anealing the material first and then heat treating to give the correct temper for the finished article. Just be aware that this material is frequently found in aggressive heat and chemical environments for parts subject to a lot of mechanical stress so there may be legal conditions that are attached should parts modified fail resulting in a safety issue. Have you tried contacting tool makers with your problem. The makers of these specialist metals as not going to be very helpful as they also offer machining services and might also be ducking any legal implications in offering advice that leads to deffective parts. Regards - Pat

[wildwestpat]

Hi dmatt

If the USA has the same aero space quality controls as the UK? Assuming this is so then I would talk to the 'Inspection Authority' as soon as practical as they may have some angle on the tracibility of parts and that will include any modifications carreied out after the origional manufacture of that part. Here in the UK there is a register of every part right down to the humble plain washers that form part of a machine that is to 'fly' right down to where the material came from and where the part was made and inspected for quality. [The description 'fly' includes a number of civilian and military uses.] To modify a part and refit it for 'flight' requires inspection, quality control and history to be recorded by the appropriate 'Inspection Authority'. Build and inspection records are maintained for years and years so that in the event of an incident the source of the failed parts can be established inorder to find other machines where the suspect parts have been incorporated. This adds a very heavy overhead to all aero space projects but is necessary for safety not only those in the air but all of us on the ground.

Good luck in talking your plans over with the Inspection Authority prior to investing in tools as they may object. I used to worked in the aero space industry and know only too well the problems that early consultation with the inspection authority can bring if this is done after the work has been started. The inspection authority will have experts on the stress and risks of fracture caused by your intended modifications.

Make sure you get paid even if the parts are rejected as unfit to 'fly'! If you are subcontracting make sure the responsiblity for the part being suitable is not your responsibilit. - Regards Pat