Briggs and Stratton 31r976-0016-g1

[Scrubcadet10]

Personally, if you have access to both sides, I would use bolts and locknuts.

This...
I use grade 8 material, just a personal preference.
bolt, flat washer, lock washer on the nut side.

 

[David357]

Personally, if you have access to both sides, I would use bolts and locknuts.

Well 3/8" dia probably wouldn't fit so what diameter would you recommend ? Also are the lock nuts the ones with teflon material in the center? Probably what I will do . Also need to figure out the size bolt that screws into the center of the pulley/ pto shaft. Would think a new engine would come with one but it didn't.

 

[David357]

This...
I use grade 8 material, just a personal preference.
bolt, flat washer, lock washer on the nut side.

Thanks iam going to go this route.

 

[Scrubcadet10]

Well 3/8" dia probably wouldn't fit so what diameter would you recommend ? Also are the lock nuts the ones with teflon material in the center? Probably what I will do . Also need to figure out the size bolt that screws into the center of the pulley/ pto shaft. Would think a new engine would come with one but it didn't.

I would take one of the self tapping bolts with you to the hardware store, and compare them.. find one closest to the diameter of the screw, just a bit smaller. and longer
Yes, locknuts have the material in the middle of them.

 

[Scrubcadet10]

Square PTO Key #1	0.25 x 2.688 x 0.145
PTO Keyway #1 (mm)	6.34 x 68.28 x 3.683
PTO Threads	0.438-20 UNF
PTO Shaft Diameter (in)	1.000
PTO Shaft Diameter (mm)	25.4
PTO Shaft Length (in)	3.157
PTO Shaft Length (mm)	80.188

straight from Briggs and stratton.

Crank threads are a .438-20 UNF.
although it's confusing why they have the first number in thousandths of an inch... not a fraction...

 

[slomo]

Hate to say this but after a few broken taps that had to be cut out with carbide bits I no longer use any oil when tapping aluminum. I have even broken them using Tap Magic tapping oil.

Just use whatever you want as long as you are prepared to cut out a broken tap as tap extractors don't work either once you break one off in aluminum.

A hardened steel tap shouldn't break in soft aluminum. Might get a Craftsman tap and die set. Those have been good IMO.

slomo

 

[StarTech]

That is converted to SAE 7/16-20.

 

[StarTech]

A hardened steel tap shouldn't break in soft aluminum. Might get a Craftsman tap and die set. Those have been good IMO.

slomo

Shouldn't break is different than real life as I have broken several Vermont American taps off in aluminum Kohler cylinder heads The last one shattered so it was a lot harder to drill out with the carbide bit. And this just by using the t wrench that comes with the taps. The taps just gall in place and can't be turn one or the other with snapping them. Ever since I started using the alcohol per my machinist which does SpaceX work I haven't had a single tap to jam in aluminum. Matter of fact they cut better threads.

But I can put it off as me having having to much strength as I have broken several screw/bolt extractors too but they were cheap Chinese versions and I got a set of 6 bit coming from my machinist tool supplier that costed me $55 so I will give them a test.

 

[David357]

Square PTO Key #1	0.25 x 2.688 x 0.145
PTO Keyway #1 (mm)	6.34 x 68.28 x 3.683
PTO Threads	0.438-20 UNF
PTO Shaft Diameter (in)	1.000
PTO Shaft Diameter (mm)	25.4
PTO Shaft Length (in)	3.157
PTO Shaft Length (mm)	80.188

straight from Briggs and stratton.


Crank threads are a .438-20 UNF.
although it's confusing why they have the first number in thousandths of an inch... not a fraction...

Wonder where I can order that pto bolt / washer from , I looked online but nothing comes up in the search.

 

[Scrubcadet10]

That is converted to SAE 7/16-20.

You need a 7/16-20 bolt... any hardware store should have them....