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margo
09-28-2006, 05:54 PM
Trying to drill prop shaft using bits for ss. won,t touch it....There,s a 3/8ths hole in the center about 1/4" deep very rough inside looks almost like a weld slag why i don,t know...Tryed to start with smaller bits won,t even put a dent in it....If there was a way i could grind it flat then punch it maybe but how....Any help please i wan,t that ss prop...thanks Joe

mrfixxall
09-28-2006, 06:09 PM
Volvo? 3/8 Is Too Big,its A 5/16 Alen Head....screw The Nose Cone On And Use The Rite Drill Bit For The Threads Your Using.....the Nose Cone Will Act As A Guide When Driling.....use A Coldbalt Drill Bit And Drill Slow Vary Slow Because The Ss Prop Shaft Will Guld And Become Hard And You Wont Be Able To Drill It..

MOP
09-28-2006, 08:06 PM
Sounds like it was drilled and somewhere along the line the bolt got broken off and distroyed trying to remove it, the hole normaly has a nice counter sink reasonably easy to drill. Tough fix! Best way is to get it weld filled then grind smooth and center punch it, you need a very good carbide bit maybe two and cutting oil. Using regular oil will not do the job it will only help to ruin the bits, been the done that more then a few times. Like MF said drill slow with heavy pressure!

Phil

penbroke
09-28-2006, 08:33 PM
Maybe a broken tap in there? Then sombody drilled a larger hole to try one of those tap extractors. There is no other reason I can think of to drill a 3/8" hole in the end of the shaft. The shaft is NOT that hard or tough to drill. A broken bolt should be easy enough to drill. Even a stainless one. A broken tap or drill on the other hand can be tough to deal with. If that is the case you may have to remove the shaft and drill it out in a lathe.


Frank

MOP
09-28-2006, 08:55 PM
Excellent point Frank!!

Rootsy
09-29-2006, 06:35 AM
i concur with frank... even a grade 8 SHCS will drill... not easily but you can cut it... if all you are doing is turning the drillbit... then there is a broken tap in the hole... nothing short of a stubby carbide drill is going to cut it and that is IFFY... if you can get a HARD and i mean HARD punch... you MIGHT be able to shatter the tap and fish the parts out of the hole... it'll be challenging...

and if this is the case and you bugger it up removing the broken tap.. you can always drill and tap oversize and install a thread insert :)

margo
09-29-2006, 11:04 AM
Thanks for all the info.....The broken tap theory sounds like a possibilty....will try again if all fails will stick with the aluminum prop....Thanks again Joe

mrfixxall
09-29-2006, 01:40 PM
Thanks for all the info.....The broken tap theory sounds like a possibilty....will try again if all fails will stick with the aluminum prop....Thanks again Joe

Theirs another way to keep the prop but from coming off,ive ran mine this wa for many years.....take the prop cone and tap the center to a 3/8 thread,then thread a allen set screw in it(mine was 1'' long)apply locktight blue to threads of the prop shaft then tighten prop cone then tighten the set screw...if you have left hand rotation,with the way the threads (rt hand tightening)it wont unthread and you wont loose the prop.

margo
09-29-2006, 03:38 PM
to mister fixall i think i under stand what you,r talking about but where do i get the female threads to screw into without getting the piece ou of the hole...I,v been probeing around and it does look like a broken tap ...Can just bearly make out the shape of it ....looks like someone tryed to drill it out and made it worse..Maybe a dumb question but would heat ruin anything like seals or whatever...Say a small acetelene torch tip right in the center...Thanks again Joe

penbroke
09-29-2006, 08:10 PM
The female threads would be on the inside of the prop cone. You would have to drill int inside to the proper size and tap it. The cone would be screwed onto the prop shaft clamping the prop in position. The 3/8" set screw would be screwed into the cone and down against the end of the prop shaft. This would bind the cone and prevent it from un-screwing, much like jamming two nuts together on the same screw.

Nice solution there MrFixx.:yes:

You might be able to reduce the hardness of the tap that is jammed in the hole by heating it. This might allow it to be drilled out. I'm not sure. Try to limit the heat to the tap as much as you can if you try it. The seals are far enough from the end of the shaft that they should be ok if you're carefull. You could use wet rags or running water to keep the shaft cool where it enters the housing.

Good luck and keep us posted.

Frank :crossfing

maddad
09-29-2006, 09:43 PM
You could stick the lower in a bucket of water with just the shaft out when you heat it.

margo
09-29-2006, 10:24 PM
thanks again you guys got some great ideas will keep you posted Joe

Ted Guldemond
09-30-2006, 08:58 AM
Most taps are of a carbon content that the annealing process is long and slow. Mr.Fixall's solution sounds like the safe way to go.

margo
09-30-2006, 03:23 PM
After hours of trying with no results I,v decided to go with mr.fixall and will tap the cone ...This sounds like the easiest way out....Using this system can do you use the original cone or the one for a long shaft Joe

MOP
09-30-2006, 05:03 PM
Tapping the cone is not new, Volvo did it for a few years but dropped it not sure why. If you go that route Heli Coil it like the factory did, in the link below you can see the factory piece.

http://216.37.204.206/Shorts/Volvo_oem/Volvo.asp?Type=13&A=4&B=172

Phil

Lenny
09-30-2006, 07:46 PM
Margo, I had my prop shaft removed from the leg, then had it chucked up in a lathe, then drilled from the tailstock on the bed. More work, but a certain, perfect fix...

:)

Lenny
09-30-2006, 07:48 PM
You could also just replace the propshaft with a true, used one already with a hole, and get them to transfer your 1:61 gear set on the end.

BigGrizzly
10-02-2006, 09:28 AM
here is another fix. Get a 1/8 solid carbide gringing bit ,cone shaped and a hig speed die grinder a Dremmel will work and slowly grind the tap away by going straigh in ,not around.

BigGrizzly
10-03-2006, 08:54 AM
Got your E-mail but not the privat message. The bolt going through the shaft was don because the thread pitches are different so if the hub(nut) losend it tightens the allen bolt. if you drill and tap the hub and it losens so does the bolt because it is part of the hub now. Since the new props look like flow through but are not on that drive you can even safty wire the hub to the prop on the inside. I just like keeping it like Volvo designed it.

joseph m. hahnl
10-05-2006, 05:46 PM
:crossfing they make hard cut drill specifically designed to drill thru taps. . you could also have it burned out with an EDM for about $50 bucks


Grind the tap flat with the dremel. try not to change the hole dia .
once its flat you can use the hole to guide the hard cut drill.

these are negative cutting drills and dont have any flutes.

When you work on materials that cost thousands of dollars a broken tap
is not an issue if you have the proper tool.


goood luck:crossfing

joe