Case savers, what kind?

[tadd]

So a search on case savers says that it is a 'must do' for mag cases using aluminum cylinders, but I couldn't find anything on what specific kind to use.

My "Nuts, Bolts and Fasteners" book by C. Smith says he likes the rosette type best followed by the keen-serts, then time-serts (I assume this is the case savers that everyone installs), then finally heli-coils.

Both the rosette and keen-serts have a physical lock (rings or pins hammered into the case) against rotation, but they were kinda before locktight, so having a time-sert with red goo is almost as good.

Thoughts please...

tadd

[cgarr]

As your title says, Case Savers, thats what we use, and Pelican has um

[tadd]

Cgarr:
Thanks again for your wisdom coming to the rescue, but... why? Is it that case savers 'could be replaced' (although I bet it would be a B!#$h). The aerospace people use keen-serts all over the place unless you are looking at an older airplane then they are the rosan (rosette) type and, as I am sure you know, they use mag all over the place.

tadd

[Jeff Alton]

If you want to break some ground, fill your boots. Casesavers are a proven reliable method of repairing/preventing thread failures in 911 motors.

Cheers

[tadd]

Catca:
I am sorry if I offended, I just like to explore why someone has the opinion they do. I am always interested in why and how someone has come to a certan conclusion - be it actual hard data and analysis or that general unquantifiable time gained 'experience'.

Just looking to expand my knowalge base a little deeper, that was all. I appreciate all the help and advise I get on this board while I learn.

tadd

[Jeff Alton]

Sorry, my reply was a little short, not intended that way at all. I was just trying to say that the casesaver is the proven repair. That is all. Your other inserts may be a better way to go, I certainly don't know though. It may have to do with thread depth, OD of the insert vs available parent material etc, not sure. Having said that, my post was meant to say "these have been used with success for many years...... give em a try"

Cheers

[cgarr]

tadd, I know where your coming from, I have built many aircraft engines and porsche engines, IMHO the aircraft are cheaper and eaiser to build, The aircraft have things they use only because the process to get the repair approved has been done, you would not belive the paper work involved in this, this does not mean its the best out there, just the most expensive in many cases. One thing to think about, My O200 in my plane will need a rebuild in about 1500 hours, if I had an hour meter on my car it would be equal to about 5000 hours on the porsche engine

[tadd]

I'm sure both of you have come across this book by carol smith, but it is a really good read. I have read it cover to cover several times. It actually inspired me to read the SPS cataloge. Who knew fastners were so damn cool. I just never imagined how much thought has gone into this stuff.

http://www.amazon.com/gp/product/0879384069/sr=8-1/qid=1142048017/ref=sr_1_1/002-2706645-5806409?%5Fencoding=UTF8

cgarr - nice planes. I hope I get to finally chase my pilots licence, then instrument rate, finally go aerobatic. When I was nine I got a ride in a P-51 mustang at an air show (cause the biplane ride guy forgot me - I had the last ticket of the day so his buddy took me up). I have never forgotten the imelmans (sp?), barrel rolls, tail slides or the brief weightlessness on that ride. Dad was a school teacher so even though I managed ground school I could never afford flight time. Then came college, then way too many years of graduate school and then a post doc. FINALLY comes a job, so after paying off all the other crap (school, home, ect) it is time for toys. Porsche first, plane second. Need more money!

Thanks for your input. You have been invaluable.

tadd

[Jeff Alton]

Planes and Porsches! Which do you think will drain the account faster! Just kidding. I have only minimal hours but I log about 45 hours week controlling the skies!

That book you posted is rather interesting isn't it. For what it is worth, I am one of the few that has to get an aluminum case repaired. Long story. It is getting a timecert next week. In my case (not pun inteded) the smaller OD of the timecert vs the case saver is a benefit due to the larger spigot bore in the vicinity of the repair.....

Don't rule out using a different method, nothing would ever change if others did not look for new or different solutions. You seem like the type that will do his "due dilligence" before making the final descision. However, if you use something different, it would be great if you could take the time to document it and update its success for the rest of us.

Cheers

[ChrisBennet]

TimeSerts "lock" themselves in the surrounding material by expanding at the bottom. Because of that, they might not be the best solution for some situations - like stud holes in magnesium right next to a spigot hole.
-Chris

[tadd]

Just for grins and giggles, I pulled out my olde book of materials and the following fell out (all units in micrometers per mK):

Ti, 8.6
Al, 23.1
Mg, 24.8
Iron, 12
Carbon Steel, 10.8

Looks like Blue72s hit the nail on the head. I will have to hit my local bolt supplier on monday...

Catca:
As for your problem have you considered a wasted stud? We had a stud pull on a part and the local ex-F16 mechanic suggested this option (dont ask). Basicly its a stud that is say M10 on one end and M8 for the rest. Just drill the buggered hole oversize and tap. Since the only oversize part goes in the hole, you would never know the stud is 'goofy'.

Edit:
Found the pdf for rosan slimserts. Cool stuff. You can even get them silver plated. Those would be perfect for exhaust studs. I may have to call and see if they will give a few samples for 'testing' purposes. I've gotten some kick ass stuff by just asking...

Edit 2X:
Here is the link to alcoa for the rosan info...
http://www.unirexinc.com/alcoa.htm

tadd

[Jeff Alton]

Tadd, I would consider that, but mine is a head stud. Your links keep providing me with too much late night reading!

Interesting info to say the least!

Cheers