JoePavelich
Member
- Joined
- Feb 18, 2019
- Messages
- 11
Anyone know of the availability of a titanium rod for a K&B 7.5 ?
It is very difficult to use any Titanium alloy as a connecting rod material in a miniature two cycle engine! If your interested, I'll explain why from actual experience.
Jim Allen
Hello Jim, I'm interested.
What about 7068 Aluminum? Its supposed to be just as strong as Titanium without the BS of machining Titanium (or its thermal properties).
EDIT: I found this on Wikipedia (yeah I know for whatever its worth but....) "Primarily developed for ordnance applications, alloy 7068 is now being used or considered for markets like the aerospace and automotive industries (valve body and connecting rod applications)"
View attachment 275717
https://precisionarmament.com/tennalum-7068-aluminum-alloy/
Thanks,
Mike
..... Titanium connecting rods that used any type of roller assembly in the bottom end also did not work with drawn cup bearings or machined roller bearings because it is impossible to hold whatever type of hardened bushing that can be used without distorting the bushing.......
Jim Allen
Mike,
Ti is not that difficult to machine. Slow spindle speeds, heavy feed rates and keep everything cool. I've been using the same solid carbide roughing end mill to make connecting rods ( and other parts) for more than a decade.
For what it's worth, the 7068 is almost unobtainium. I had an RFQ for some 7068 parts a while back, and ended up finding some after some considerable searching. I eventually found it on eBay, tracked down the seller and bought it direct. I could only buy the drops they had left over from purchases made by military contract MFRs, and only if those drops weren't potentially sought by those MFRs (these drops were what was on eBay). I still have most of what I bought, and I hold it fairly close to the chest.
Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC
Jim, did you ever use loose needles in your steel con rods??
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