Briggs n Strappon crank bolt help.

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Ok maybe mispelt that.

I have a Briggs n Stratton motor here a small project I'm working on. I noticed the impeller isnt on tight and found the crank bolt wont tighten.

Looks to me like some numpty fitted the wrong thread and or bolt too long. I've checked and its 11mm diameter but not sure sure if it may be a standard unc unf thread up in crank. Hard to see, this sort of fits but looks a bit chewed. Any ideas anyone? Pic of bolt I removed.

15746793173066337687671238526203.jpg
 
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Drill and tap it out to a suitable metric size maybe m10 or m12 I would think.:unsure:
Mind you the cost of a tap and drill if you do not have them already might make it uneconomic.
 
I think the original is 7/16" UNC but I agree with footprints - tap out to 12mm.
Bit of bad luck, that one :eek: but the crankshafts are pretty soft.
John :)
 
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Thanks chaps yes I spun an m10 tap in there and it seemed loose. It spun when it hit the end. So I guess m12 although a tried a primary m12 tap and It felt real tight soon as it started to cut I'm concerned I may snap it off. Looks like I may have to drill it out first. I have a m12x1.75 tap apparently I need a 13/32 drill ffs pia!
 
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If you want to know if that bolt is UNF or UNC (or metric fine), ideally use a thread gauge. Really handy. Metric fittings are measured in pitch 1.0mm etc, UNC/UNF/Whitworth are measured in Threads Per Inch.

That said, with your caliper you can measure the pitch/TPI accurately anyway, though not the angle.

Using your caliper - count 11 threads, tip to tip, and report back how many mm it is.

Nozzle
 
I'll stick my neck out and say 10.5mm as a tapping size, although my book says 10.3.
What's your project?
John :)
It's a leaf vac. Basically we have a few leaves to pick up in our garden! I picked up an old Billy goat 8.0hp vac unit off ebay recently but the rest of it was knackered in fact it looks like they even replaced the engine. I want to bolt this on my trailer as my sit on mower isn't man enough. This will act as the vacum and suck through the sit on mower. Look on YouTube at diy leaf vacs (y)

I'm just in the process of stripping it all down as i need to weld up the front face as it was originally designed as a ground vac plus addon vac pipe.
 

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Brilliant machines! (y) I have a KD612 with a 6hp Briggs 6hp side valve motor plus a vacuum hose.
What is ridiculous though - a hose kit is around £250 and similarly if you need a new bag :eek:
Good luck with your project!
John :)
 
Brilliant machines! (y) I have a KD612 with a 6hp Briggs 6hp side valve motor plus a vacuum hose.
What is ridiculous though - a hose kit is around £250 and similarly if you need a new bag :eek:
Good luck with your project!
John :)
Aha nice one John looked yours up still a nice machine, mine came without a hose kit but I sourced some hose off ebay which fits and it's very good quality hose in a green n black finish. Will paste you details later if interested. Then of course all you need is a bit of stainless tubing and clips the lot for easily under 100quid.
 
I was lucky to find my machine with the hose kit, and importantly the plate that slides underneath to blank off the scoop.
Ive no idea how old it is, but it was a one owner machine.....cost me £400 and it hasnt had much use.
Id be interested to see a pic of yours when its done, and hope the work goes well......just what you need in these days of eternal rain!
John :)
 
Ok my dad bent my ear about the tap I was using blah blah pitch etc. He's sending me a bolt and tap to match good old dad. Thanks again for your help chaps. Will post some pics up as I progress.
 

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