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prop bolts 3/8 or 7/16. does it matter?
- Thread starter pilot2512
- Start date
terry.mortimore
Well Known Member
Prop bolts size
Hi Jay, check your tape measure. 7/16" bolts are larger than 3/8".
I have the smaller 3/8" bolts and I'm wondering if they will be suitable. I"ll be using a 4 inch extension with a ground adjustable Sennsenich prop. I haven't asked the question yet, but it's getting close.
If you still want the 3/8" I'll trade ya
Terry
Hi Jay, check your tape measure. 7/16" bolts are larger than 3/8".
I have the smaller 3/8" bolts and I'm wondering if they will be suitable. I"ll be using a 4 inch extension with a ground adjustable Sennsenich prop. I haven't asked the question yet, but it's getting close.
If you still want the 3/8" I'll trade ya
Terry
LifeofReiley
Well Known Member
AX-O
Well Known Member
at the end of the day it does not matter (as long as the horse power has not been dramatically upgraded). You will need a prop extension. Get it from Saber.
One side of the prop extension will have the engine bolts, the other side will have the prop bolts.
I have a 320 with 3/8 on the engine and 7/16 on the prop, I have a 7/16 on the engine and 7/16 on the prop. I just ordered one with 1/2 on the engine side and 7/16 on the prop side.
Keep what you got.
Edit: posted at the same time as Reiley.
One side of the prop extension will have the engine bolts, the other side will have the prop bolts.
I have a 320 with 3/8 on the engine and 7/16 on the prop, I have a 7/16 on the engine and 7/16 on the prop. I just ordered one with 1/2 on the engine side and 7/16 on the prop side.
Keep what you got.
Edit: posted at the same time as Reiley.
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smokyray
Well Known Member
Size matters...
Jay,
If you bolt on a wood prop, the 7/16" bolts hold torque easily to 25 hours, the 3/8" not so much. When I built my 4 it had a Sterba woodie and 3/8" bolts. I checked my prop nuts every 10 hours, more often than not they weren't up to 22ft lbs. After switching to 7/16" bolts, the problem went away. 0-360"s use 7/16" bolts (or 1/2), size does matter!
Since Craig's props don't "swell" like wood props, 3/8" prop bolts for an 0-320 would be ok. However, the first Catto RV prop was on my 0-320 powered RV4 with 7/16" bolts!
I know what I would do...
V/R
Smokey
Jay,
If you bolt on a wood prop, the 7/16" bolts hold torque easily to 25 hours, the 3/8" not so much. When I built my 4 it had a Sterba woodie and 3/8" bolts. I checked my prop nuts every 10 hours, more often than not they weren't up to 22ft lbs. After switching to 7/16" bolts, the problem went away. 0-360"s use 7/16" bolts (or 1/2), size does matter!
Since Craig's props don't "swell" like wood props, 3/8" prop bolts for an 0-320 would be ok. However, the first Catto RV prop was on my 0-320 powered RV4 with 7/16" bolts!
I know what I would do...
V/R
Smokey
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LifeofReiley
Well Known Member
SmokyRay... I'm pretty sure 360's use 1/2" bolts. Well, at least all the ones I've seen have used 1/2" bolts.
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smokyray
Well Known Member
Absolutely!
Reiley,
You are correct sir, the 0-360 flange bolts are 1/2". However, many FP RV cowlings require an extension which attaches to the flange with 1/2" bolts and 7/16" or 1/2" through the prop. Craig Catto's and many other prop makers allow both options.
I opted for the 1/2" flange/Saber extension bolts, 7/16" prop bolts on my RVX 0-360J2A
V/R
Smokey
SmokyRay... I'm pretty sure 360's use 1/2" bolts. We, at least all the ones I've seen have used 1/2" bolts.
Reiley,
You are correct sir, the 0-360 flange bolts are 1/2". However, many FP RV cowlings require an extension which attaches to the flange with 1/2" bolts and 7/16" or 1/2" through the prop. Craig Catto's and many other prop makers allow both options.
I opted for the 1/2" flange/Saber extension bolts, 7/16" prop bolts on my RVX 0-360J2A
V/R
Smokey
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