Reply With Quote....let the bushing provide the press fit not the bore of the strut........just my .02
huh? what? yea, what ever you do... don't let that fiber bushing open the bore on that chromemoly barrel
so do you plan to bore / ream to size before you weld or after??
....let the bushing provide the press fit not the bore of the strut........just my .02
huh? what? yea, what ever you do... don't let that fiber bushing open the bore on that chromemoly barrel
huh? what? yea, what ever you do... don't let that fiber bushing open the bore on that chromemoly barrel
let me help ya here...standard bores of strut barrels are 1.250 for 1", 1.375 for 1 1/8", and 1.500 for 1 1/4"...no need to bore a strut to fit a particular bushing...why not make the more easily machinable bushing fit a standard bore of a strut that is under a boat when you need to replace it.....:sqeyes:
The Steel struts are Heat treated...
Heat treated as in normalized or heat treated as in quenched and then brought back to a Rockwell hardness # in a draw furnace ?
If the struts are mild steel they cannot be heat treated as there is not enough carbon in the material. If the struts are a high carbon steel then stick welding with the right rod and heat treating is possible.
I intended on fabricating the strut and having all the machining done afterwards.
On the strut I have now he was able to turn the whole thing in a lathe to bore the bushing OD farther as I cut the strut off and moved the prop ahead 2.75 " and put in a new bushing.
If a mild steel strut was OK then a strut could be fabbed using a T section of a steel beam and that would eliminate the upper weld. It also would leave a nice radius where the mounting plate met the vertical plate.
Someone needs to relay EXACTLY what material the strut is made of.
I sawed mine off and it seemed like mild steel to me.
Making it be a billet piece sounds interesting but the material and machining cost would be high. I suppose I could saw a lot of the excess material off before machining.
This guy was fabbing up stainless tanks for Genesee beer here in Rochester NY. Big tanks that they walked on while working to give you an idea. I would guess 20-30' in diameter. To weld the top on, they had a real big mig welder on tracks that did the welding all by its self.
Be good, Jim
That sounds like a submerged arc setup. I've done a lot of that. The machine runs on tracks and there is a granular flux that covers the weld puddle. You don't need a welding helmet as there is no light and no smoke. The weld is X-ray quality and is extremely smooth. We used that on overhead crane girders. The welds would sometimes be 80' long nonstop.
Starting with a billet you would have a lot of extra material but with a CNC you would only have 3 set ups. One for each side and one for the bore. Do the rough machining before heat treating, final machining after, and the final bore work last. You could use either a carbon steel like 4140 or a stainless like 17-4 or even a 400 Series like 416. I would probably go with the 416 just because I work with it a lot. A drop thru would be easier, a standard bolt on style would require an additional setup to drill the mounting holes.
Cost would be high for a single unit but if someone wanted 10-20 pieces the price would drop a lot.
Thanks for all the great replys here. I've done my share of fab and machine work to not let making my own parts bother me. It's not rocket science.
I'm looking for the answer to Unchained's question of the heat treat, weather it's for normalization, or for hardness. I would guess normalization.
I'm also guessing you can get tubing for the barrel with a bore that's already correct, maybe even honed. I'm guessing there's not much more than .0015-.002" press between the bushing and barrel. Machining the barrel after welding the fin on it could be tricky business. I know ultimately you want the barrel perfect, but fortunately, I think the bushing will allow for a couple thou of distortion.
Is there any benefit from one to the other between chromoly or stainless? Does the stainless need to be heat treated as well?
The input on weldng is appreciated. I wouldn't have thought stick was necessary. Is a groove machined in the barrel to recieve the vertical piece? This will be a drop through, so I don't have to worry about a mounting pad on top.
Again, thanks for all the input. I know this is an important part, and I take it plenty seriously. I just think the prices I've been quoted are completely rediculous.
Starting with a billet you would have a lot of extra material but with a CNC you would only have 3 set ups. One for each side and one for the bore. Do the rough machining before heat treating, final machining after, and the final bore work last. You could use either a carbon steel like 4140 or a stainless like 17-4 or even a 400 Series like 416. I would probably go with the 416 just because I work with it a lot. A drop thru would be easier, a standard bolt on style would require an additional setup to drill the mounting holes.
Cost would be high for a single unit but if someone wanted 10-20 pieces the price would drop a lot. If you were using a billet, why would you heat treat?
I planned on making my own strut because I intend on changing prop shafts up to 1 1/8". I intended on making it out of stainless material.
I've fabricated steel for decades, have had all position stick welding certifications and have no reservations about making it myself.
Is that a fact or a speculation that the boughten struts are indeed made out of chrome moly material ? Alloys typically don't stick weld good and are crack prone on heavier materials.
I would have guessed that they were made out of cold rolled mild steel which would stick weld good and flex with out cracking.
The strut that I have in there now is an 8 degree strut but I determined that the strut is mounted at a 7.5 degree angle to the keel.When I called for a price, the two options I was given were stainless, or chromoly.
Would you be comfortable with a tig weld on the Chromoly? What about the stainless?
We normally get our billet a little softer so it is easier to machine. We then shape it a little oversized, get it heat treated to Rockwell "C" 40-42, (our stuff is not boat related) which gives a tensile strength around 182,000 psi, then do the final machining. Doing it that way allows us to clean up any wrappage from the heat treating and still get good tool life. We also offer a Cyro treatment which stabilzes the grain structure giving it a little more strength.
When I called for a price, the two options I was given were stainless, or chromoly.
Would you be comfortable with a tig weld on the Chromoly? What about the stainless?
You certainly could TIG weld the chromoly or the stainless fine but you would either have to weave your bead to get some cross section or run multiple passes. I would guess weaving would be better. For the chromoly material preheating before welding and peening after welding might offset some shrinkage too.
What price did you get on a complete strut ?
I would do all the machining after the fabrication. As I stated in the previous post the machinist I used put the end of the strut barrel in the chuck and turned the whole strut in a lathe.
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