JD Front mount 59" blower

[xkbal]

Again, I have no issues with however anybody wants to operate this equipment. I even operate some equipment contrary to the way planned by the manufacturer. I just think if you're going to do that you should at least understand what the starting point is. In this case the starting point is that as designed there is shear bolts for the auger. Period. If one wants to experiment that is fine.

My blower was assembled by the dealer according to the Deere manuals. Unless someone can provide some documentation from Deere to prove otherwise. The operations manual only references the auger shear bolts. The parts manual provides the part numbers for the keys to be installed in the universals.

Rob, I expect you missed the key. That is fine if that is how you want to operate the blower but it means you can't get full power to the blower as that 1/4 ' bolt is now the shear bolt for the impeller AND auger. Just because your dealer agrees with you means very little, all the Deere documentation disagrees. The date on the parts manual I looked at online appears to be March 6, 2012 and it still shows the keys I've described. So you are modding the equipment from what information is provided by the manufacturer, unless you think your dealers opinion overides the manufacturers written documentation. I'm more than willing to admit i'm wrong, all I ask is that someone provide documentation (ops manual/ parts manual/technical bulletin). That being said, I've left enough information on the thread for people to make an informed decision so I'm done.

 

[Rob-D]

I think you'll find that what you're looking at is not a shear bolt. If the key was not installed, contrary to what the online Deere parts manual shows, then you can experiment with that bolt acting as a shear bolt. I had no luck doing that. The spare shear bolts you refer to are for the auger and have been there for a long time, it's the impeller that is missing protection. If you have a look at your operator manual it will likely only reference the shear bolts on the auger. If it mentions any other shear bolts please let me know and I'll discuss it with my dealer.

Here's the key part number from the manual and attached is the picture from the parts manual showing the driveshaft you mentioned.

20 M84550 Shaft Key 1 (3120, 3320, 3520, 3720 CUT)

View attachment 286666

OK, I just went out and checked my shaft which is off as I didn't use my blower last year. What I found was indeed a key and a bolt that I had put in a plastic bag and left with the shaft, so I would say there is no specific way to prevent the U joint from breaking if there is a jamb in the shoot impeller. Reading the info with my blower it mentions being careful when crossing a gravel area. I'm wondering if this blower is not intended for gravel driveways. Anyway, I'll have to decide how I will handle the problem as I'd rather not blow up a U joint. What Deere's thinking on this is I have no idea, my 47" blower, as I stated previously, does have shear bolts on both the impeller and the rotor. I do remember that I don't run the blower at PTO speeds until after the driveway is frozen and there is a layer of snow down so that I no longer shoot rocks out the impeller.
Has anyone contacted JD on this? I'd like to know their answer.
Rob

 

[dschuffert]

Thanks xkbal. I learned a lot from this thread. I assembled the unit myself and made a lot of assumptions on what the different bolts were for. I thought the key and bolt that hold the driveshaft to the gearbox were both shear types of material (similar to small engine flywheel or crankshaft shear keys, etc.). You are correct that John Deere lists the key as a "shaft key" and nothing about it having a shear rating. I found Woodruff shear keys all over the internet but not sure what to try yet. I would like to find a Woodruff shear key that fits this application, and shears at a point before the join fatigues, but not sure what the numbers are yet.

 

[Rob-D]

I would try 6061-T6 or 2024 aluminum first. Key material is generally made from lower carbon steels, 1018, etc, you can try leaded steels if the aluminum doesn't hold up to your conditions. If it does fail I would go to a leaded steel, 12L14, 12L15. These are available in small quantities on the net. You can try Speedy Metals, they should have all materials I mentioned.

For the benefit of my friends on TBN I just measured the Rockwell Hardness of the key supplied with my blower. It measures 43 on the Rockwell C scale. This means it is medium hardness, 12L14 (the "L" stands for leaded) for example measures about 14 Rockwell C.

It's probably a good bet to shear before the shaft breaks but I would start with the aluminums I mentioned, that's what I'm going to do. I'd rather change material than shafts!

Hope this helps and thanks for bringing this to our attention. I remember thinking about it at the time I put my blower on and should have researched it further.
Rob

ps: aluminum has been used as a shear material in keys for years. Briggs uses it on their flywheels, any of you who have ever repaired a Briggs engine or other small engine can attest to this.

 

[jjmarotz]

A good idea is to also grease the cables that turn the shoot, they rot out quickly and I've changed them more than once. Grease helps keep them from rotting.
Rob

On the subject of these cables.
http://www.tractorbynet.com/forums/john-deere-owning-operating/232106-59-blower-cables.html

 

[Rob-D]

On the subject of these cables.
http://www.tractorbynet.com/forums/john-deere-owning-operating/232106-59-blower-cables.html

Thanks for the info.
What I've found here is that the salt used on the roads deteriorates the cables prematurely.
Rob

 

[Agent Blue]

I recently purchased a 3 year old 59 snow blower. While making brackets to adapt it to my 4110 I noticed the drive shaft did not have the key in the key way. I thought someone may have forgot to put it in but now it makes sense. Thanks for the info and I won't be replacing something that should not be there. I could not find a 47 and this 59 came up at a reasonable price. The future calls for an upgrade to a 30-40 horse power model and this will transfer.

 

[Rockgod]

Quick update:

Finally arrived yesterday, let it snow!

 

[Rob-D]

Beautiful! You could go commercial with that rig.

 

[Rockgod]

Beautiful! You could go commercial with that rig.

Thanks Rob!

Commercial, I might have to. These types of deals have a way of emptying on the ole bank acc. Thank god for 0% for 60 months.