Snow B2650 Snowblower / Main Drive Chain Gear

[sundancekid]

I continue to have failure with the tension pins (slotted spring pins) breaking on the chain gear drive. They are a huge pain to remove and replace. I've seen posts here that recommend welding the chain gear directly to the shaft. Just wondering if there's any risk with this solution. Also wondering if there are stronger tension pins that would be an option.

Any advice on this topic would be greatly appreciated. We've got 110 inches of snow here at Sundance UTAH. I'd much prefer to spend more time removing snow, and less time replacing these tension pins.

Thanks to any one who responds.

 

[yooper jim]

I have a BX2750 (looks the same as a b2650) blower and it doesn't list any tension pins. What's a tension pin? Do you mean shear bolts?
Jim

 

[irvingj]

sundance-- rather than weld it, would it make sense to have the shaft machined for square keystock? (Yes, I know, that would be a lot more $$....)

Or, how about a stainless/stronger pin? (Check out smallparts.com)

yooper-- a tension pin, aka spring pin, is like a small section of tube, made of spring steel, with an open slot along its length. It gets driven into a drilled hole that's just a tad smaller in diameter than the pin- the open slot on the pin closes up as it's tapped into position, while the springiness of the pin holds it firmly in place. Ordinarily they work well, but as sundance said, they can be a pain to change, as all three of the broken pieces have to be driven out with a drift punch of just the right diameter. Sounds like it's acting as a shearpin in this case, but not anywhere near as user-friendly as a bolt!

 

[yooper jim]

irvingj
Thanks Around hear we call them roll pins. The BX2750 has just such an arrangement. Two 5/16 - 18 NC X 1/2" set screws @ 90 degrees to each other. One is over the key. Is that an improvement in the BX2750 over the B2650 blower?

sundance
I'd spend a little $ to get a keyway cut in the shaft and a keyway broached in the sprocket, as irvingj suggested. Seems to work. Welded means you can't get it apart, if you have to.

Here is a PDF of the setup for a BX2750.

 

[Scrambler82]

Not familiar with the unit but can the shaft handle a larger pin, maybe a solid pin with locks on the ends vs a spring pin ?

Just thinking out loud.

 

[moship]

One trick I have used in the past if staying with the roll pin is to put one inside of the other. ie: use two of them. Another option would be the use of a coiled spring pin. See attachment.

The above can be considered if staying with the same design. The other options that require machining are probably better.

Additional thought...

1) Can the hole be enlarged? 1/32" or 1/16" This can increase the double shear strength by approximately 50%

2) 300 series Stainless pins typically have 60% of the double shear strenght of the standard 1070-1095 steel or 420 stainless.

 

[yooper jim]

Does the B2650 use these roll pins as shear pins for the impeller? Is there a shear bolt on the impeller? Just curious.
Jim

 

[leonz]

I continue to have failure with the tension pins (slotted spring pins) breaking on the chain gear drive. They are a huge pain to remove and replace. I've seen posts here that recommend welding the chain gear directly to the shaft. Just wondering if there's any risk with this solution. Also wondering if there are stronger tension pins that would be an option.

Any advice on this topic would be greatly appreciated. We've got 110 inches of snow here at Sundance UTAH. I'd much prefer to spend more time removing snow, and less time replacing these tension pins.

Thanks to any one who responds.

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About your snow blower the spring/roll pins are a
safety valve for your snow blower.

They are breaking from overload which what they are
supposed to do.

Your snow type is what is referred to as "Cascade Concrete"
in the removal BIZ.

This snow is very heavy and very dense and your snow
blower is simply overloaded.


The last thing you want to do is weld the sprocket to the shaft
as it will only make things much worse.


You will need to work in the slowest gear to remove the snow
you have to deal with.

I know its probably what you did not want to hear but it all comes
down to basic physics -action and reaction.

I will tell you to invest $30.00 U.S.D. in one of
Clarences impeller kits for for snow blowers as your
impeller is obviously overloaded from too fast a
forward speed or reverse speed with snow being
rammed into the cross auger.

You might as well invest in a tractor radio and put it on
the fender if you do not have a cab. Their are several good
builders of all weather tractor fender radios