Vintage shear pins

[Grampsmotor]

Recently acquired my grandfather's 'ol 5hp Johnson TD-20. A great little workhorse from what I've seen and read. I've read this was a very popular motor in its day, with many produced from '46 - '49. With that said, I'm having a bear of a time finding any shear pins for this motor. I've learned it takes 9/64 x 15/16, or Olson #2. What an odd size! Not only can't I find any shear pins of this size, I can't even find brass rod to cut my own.

Surely there are other TD-20 owners out there that know the secret. Care to enlighten a newbie? I've tried the next size up 5/32 and it's too big. My only option seems to be 1/8, but that seems too small.

Thanks

 

[F_R]

Re: Vintage shear pins

So, I sez to myself, I sez "that can't be right". So I went out and pulled the prop on my TD and sure enough it is a 3/16" x 7/8" pin. Stainless Steel. The TD models have a slip clutch inside the gearcase that keeps from destroying all the goodies when you hit the rockpile, thus the stainless steel. If you enjoy changing shear pins on the water, use brass. Otherwise, enjoy the benefits engineered in and use stainless steel.

 

[RobG]

Re: Vintage shear pins

What you could do is buy a cheap 9/64" drill bit and use a dremel tool to cut it down to 15/16", I've made similiar shear pins like this and haven't had a problem.

Rob

 

[F_R]

Re: Vintage shear pins

of course rob and I were typing at the same time. You don't want 9/64", you want 3/16".

 

[Willyclay]

Re: Vintage shear pins

How about using a 3/16" SS hex or carriage bolt with the head and threads cut off?

 

[CATransplant]

Re: Vintage shear pins

Well, the OP said that the 5/32 pin was too large. Something's not computing here. If it's too large at 5/32, the 3/16 pin isn't going to fit. Could there have been a change in there sometime at the factory on the TD-20?

Either that or the hole is messed up, in which case running a 3/16 drill through it should remove any burrs or whatever.

In any case, sending the guy for a 3/16" SS pin isn't going to help if he can't get a 5/32" one through the hole. 'Tis a puzzlement.

 

[Grampsmotor]

Re: Vintage shear pins

I got the sizing from this site: http://hoodad.fortunecity.com/index2.html and verified the diameter with a 9/64 drill bit. A 5/32 (next larger size) will not fit. If you use SS aren't you worried about stressing or splitting the rubber drive hub? Assuming I can even find or make the shear pins, that would be easier to replace than the nearly 60 year old rubber drive hub. The hole is clean with no burrs.

I'm guessing here, but wouldn't the original material have been brass?

 

[F_R]

Re: Vintage shear pins

Sorry, I goofed. I thought we were discussing the TN models, not TD, so my info is worthless.

 

[Grampsmotor]

Re: Vintage shear pins

Anyone with a running TD-20 out there?

 

[ezeke]

Re: Vintage shear pins

What is the OEM drive pin part number?

 

[Grampsmotor]

Re: Vintage shear pins

The parts manual shows it as 300-592. Description is vague - Propeller drive pin.

 

[ezeke]

Re: Vintage shear pins

Try sea-way.com in Seattle, Washington.

 

[eavega]

Re: Vintage shear pins

Try sea-way.com in Seattle, Washington.

Definitely. These guys so far have me batting 1.000 in parts for my old outboard.

-E

 

[CATransplant]

Re: Vintage shear pins

I did an extensive search for you, with no luck. Keep looking on eBay. Just search for Olson #2. Eventually someone will have some NOS ones for sale.

In the meantime, you may just have to cut your own from 9/64" drill bits. No biggie, really. Try an abrasive wheel in a Dremel or nick them with a file and snap off the pin in the vise. They won't be stainless, but...

 

[Grampsmotor]

Re: Vintage shear pins

CATransplant and all,

Thanks for the assistance. I am just amazed at how hard this part is to find. I've put in my request to sea-way and anxiously await their response. I'll keep you posted.

Your idea of the 9/64 drill bits is a good suggestion. My only concern is aren't these possibly too hard? Wouldn't the original have been brass? There is nothing in the drive line to absorb the shock of a prop hit. There is no clutch in this model.

 

[CATransplant]

Re: Vintage shear pins

Well, if the original was brass, then you need brass. I simply don't know the composition of that particular shear pin.

9/64" brass rod appears to be unavailable, after a long search. This is going to be a tough nut if you can't use steel.

Is this a through and through shear pin or one of the ones that lays in a groove in the prop? If it fits into a hole in the prop shaft, I'd seriously consider enlarging the the holes to 5/32, a size that is readily available in brass rod stock. Let me see if I can find out what the material is supposed to be.

 

[CATransplant]

Re: Vintage shear pins

Well, I found a chart for Evinrudes, but it only covers up through the 1920s. If, as you say, there's no rubber hub in the prop on yours and no internal clutch as in the TN series, then the shear pin is most likely brass. I just can't find a reference.

9/64" is equivalent to 3.6mm, or at least close enough that it's not worth discussing. 3.6mm is .03mm larger than 9/64...something a bit of emery paper would remove in one pass.

So, here's an auction from the UK, selling 10 nice pieces of 3.6mm brass rod. Who knows...you could go into business selling shear pins for TD20 Johnsons.

http://specialistauctions.com/auctiondetails.php?id=1152115

Ask the seller if he'd ship to the USA and bid. Auction ends on the 11th. Worth a shot.

Can't believe I found this. There may be other options in the metric area.

 

[rjezuit]

Re: Vintage shear pins

try www.mcmaster.com item 88605K49. Rick

 

[Grampsmotor]

Re: Vintage shear pins

CATransplant thanks for your diligence in tracking this down. I did think about going metric, just didn't consider going outside the states.

Rick - thanks for the tip on Mcmaster. I did a search with them before, but not metric, and there it was all this time.

Yesterday I tried a #8-32 screw cut to length just for testing the motor. Turns out it is a perfect fit, but was not brass. I measure .014" on the #8 and if I remember correctly 9/64 was .013". I did a search yesterday for #8-32 brass threaded rod and was able to order 1 24" piece for under $9 delivered. I realize I'm loosing a bit of strength with the threads, but I'd rather err on the side of caution.

 

[F_R]

Re: Vintage shear pins

OK, too late now, but I knew I had this chart somewhere, just couldn't find it. It is supposed to be Monel metal.