Export thread

Briggs and Stratton 31r976-0016-g1

#1

David357

David357

Recently purchased this engine to replace a Kohler cv15t motor that took a dump few weeks ago on my 04 john deere g15 commerical walk behind mower. Iam needing help to find out what diameter and length of self tapping bolts to use to mount this Briggs and Stratton 31r976-0016-g1 17.5 hp intex engine to mower. The holes are smooth right now with no threads cut. Seen somewhere online that it's a 3/8"-16 x 1 1/4" self tapping bolt needed . Can anyone verify this for me ?

Thanks David in Texas


#2

S

slomo

I would use a real tap on the threads. Same size as the mounting bolts. Use plenty of cutting oil when cutting threads.

slomo


#3

David357

David357

Okay but what size bolts ?


#4

StarTech

StarTech

Yes 3/8-16 x 1 to 1.25 long self tapping is what they use.

For tapping aluminum DON"T use cutting oil; instead, use 70% or high rubbing alcohol. Taps can jam using oil when tapping aluminum.


#5

David357

David357

slomo said:
I would use a real tap on the threads. Same size as the mounting bolts. Use plenty of cutting oil when cutting threads.

slomo
Click to expand...
StarTech said:
Yes 3/8-16 x 1 to 1.25 long self tapping is what they use.

For tapping aluminum DON"T use cutting oil; instead, use 70% or high rubbing alcohol. Taps can jam using oil when tapping aluminum.
Click to expand...
Thanks alots


#6

Fish

Fish

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


#7

S

slomo

StarTech said:
Yes 3/8-16 x 1 to 1.25 long self tapping is what they use.

For tapping aluminum DON"T use cutting oil; instead, use 70% or high rubbing alcohol. Taps can jam using oil when tapping aluminum.
Click to expand...
WD-40 works perfect cutting aluminum threads. Friends dad owns a machine shop. Learned that trick from him. Some metals, best to use certain oils when cutting threads.

slomo


#8

StarTech

StarTech

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.


#9

David357

David357

Fish said:
Personally, if you have access to both sides, I would use bolts and locknuts.
Click to expand...
Nuts ontop or bottom?


#10

Fish

Fish

David357 said:
Nuts ontop or bottom?
Click to expand...
Doesn't matter,
they won't vibrate loose and fall off.


#11

Scrubcadet10

Scrubcadet10

Fish said:
Personally, if you have access to both sides, I would use bolts and locknuts.
Click to expand...
This...
I use grade 8 material, just a personal preference.
bolt, flat washer, lock washer on the nut side.


#12

David357

David357

Fish said:
Personally, if you have access to both sides, I would use bolts and locknuts.
Click to expand...
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.


#13

David357

David357

Scrubcadet10 said:
This...
I use grade 8 material, just a personal preference.
bolt, flat washer, lock washer on the nut side.
Click to expand...
Thanks iam going to go this route.


#14

Scrubcadet10

Scrubcadet10

David357 said:
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.
Click to expand...
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.
s-l1000.jpg


#15

Scrubcadet10

Scrubcadet10

Square PTO Key #10.25 x 2.688 x 0.145
PTO Keyway #1 (mm)6.34 x 68.28 x 3.683
PTO Threads0.438-20 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...


#16

S

slomo

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

slomo


#17

StarTech

StarTech

That is converted to SAE 7/16-20.


#18

StarTech

StarTech

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

slomo
Click to expand...
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.


#19

David357

David357

Scrubcadet10 said:
Square PTO Key #10.25 x 2.688 x 0.145
PTO Keyway #1 (mm)6.34 x 68.28 x 3.683
PTO Threads0.438-20 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...
Click to expand...
Wonder where I can order that pto bolt / washer from , I looked online but nothing comes up in the search.


#20

Scrubcadet10

Scrubcadet10

StarTech said:
That is converted to SAE 7/16-20.
Click to expand...
You need a 7/16-20 bolt... any hardware store should have them....


#21

David357

David357

Scrubcadet10 said:
You need a 7/16-20 bolt... any hardware store should have them....
Click to expand...
How long?


#22

StarTech

StarTech

Scrubcadet10 said:
You need a 7/16-20 bolt... any hardware store should have them....
Click to expand...
You would think that but around here depending on the length needed even Fastenal don't have sometimes which why I order the needed length sometime out of Atlanta.GA by the the box full. This why I have a box of 3.5" ones on order now. Personally I don't like driving 45 min one way just to go to multiple hardware stores trying to find the screw. That why I just order them as I got tired of wasting a half day trying to find them.

The OP will need know to the length of the bolt that will required for his setup as it can be of any length as I use 2.5" to 5" one here. Plus will need to be at least a grade 5, preferably a grade 8.This length is in the equipment IPL, though some manufactures try to hide it so you would order the screw from them. OR as one case of a M10-150 x 155mm, even my main source of screws don't have them.


#23

David357

David357

StarTech said:
You would think that but around here depending on the length needed even Fastenal don't have sometimes which why I order the needed length sometime out of Atlanta.GA by the the box full. This why I have a box of 3.5" ones on order now. Personally I don't like driving 45 min one way just to go to multiple hardware stores trying to find the screw. That why I just order them as I got tired of wasting a half day trying to find them.

The OP will need know to the length of the bolt that will required for his setup as it can be of any length as I use 2.5" to 5" one here. Plus will need to be at least a grade 5, preferably a grade 8.This length is in the equipment IPL, though some manufactures try to hide it so you would order the screw from them. OR as one case of a M10-150 x 155mm, even my main source of screws don't have them.
Click to expand...
Thanks


#24

Scrubcadet10

Scrubcadet10

Might try looking at Bolt Depot .com, I've ordered a few fasteners from them before.
They have quite a few lengths to choose from, and you can order 1 bolt, or 500 of them ;)


#25

StarTech

StarTech

Hopefully no one took it wrong when I said I buy the box as I usually used a lot screws (bolts) for ones that are damaged or lost and just cheaper for me to do so. By the time I buy 3 or 4 screws I can buy a whole box normally.

Yes a place like Boltdepot.com is reasonably priced but I usually order thru McMasters as they usually deliver overnight a most of my repairs are time sensitive.


Footer Links 1

Top