Grading Broke an 1845 Mower Blade

[Charlie_Iliff]

Did a bunch of mulch moving, some garden tilling, some gravel spreading and some mowing over the weekend. All worked great, except:...
A couple of wires (starter) broke and had to be put back in the main junction box. I don't know if they were stressed at installation or something poked them when the cover was off. I've had a little trouble keeping it on.
A finish mower blade broke. Fortunately, this is the finish mower set which bolts on the stump jumper in the 6 foot rough-cut deck. Each spindle has four short blades welded to a heavy ring that bolts to the stump jumper in place of the hinged rough-cut blades. This isn't the configuration of any other finish mower, I don't think, so shouldn't be a problem for anyone not using this particular combination. I had only mowed about an hour and a half, when I managed to get the blade into a small hump of dirt and it broke. The rough-cut blades have lived through rocks, wire, stumps, etc. with nothing but a dent or two, but the finish blade ripped off the ring. I'm talking to Terry Estep at Power Trac about replacement, and maybe a different configuration.
Before it busted, the finish setup did a pretty nice smooth job. It wasn't golf course quality, but I was cutting 2 week growth. The finish blades blew out a lot more dust than the rough cut, and heated the engine more.
Searches on this board, Lawnsite and some others show a wide range of theories about cutter blade shape, and variations in preferences for different deck designs. Yet another area for research and experimentation. Anyone have a suggestion for the best airfoil shape for hinged 6 inch blades on stump jumpers under a 6 foot deck?

 

[duane]

Charlie,

Where is your main junction box located. I'm not sure that the PT400 series has a junction box.

I find it very valuable when a PT owner reports a problem and then follows up with a solution. It helps all of us PT owners prevent and/or correct similiar problems. Keep up the good posts.

Duane

 

[Charlie_Iliff]

Duane:
The 1845 junction box is in the lower right of the engine compartment. I haven't looked at the 4xx series for a comparable setup. With luck, I don't have an ongoing problem, but only the leftovers from when the lid to the box came off and some brush poked through the expanded metal.
Overall, I can't say my electrical system has been completely satisfactory, but I have been able to identify and fix problems fairly easily. I have had some trouble with the clamping force of a couple of tab connectors after being disturbed, and I ran a ground wire to tie the front and rear frames together and to the the negative pole of the battery. That way, if I have a problem I know it isn't a bad ground.
I've seen the posts, of course, about cooling fan fuses, and battery leaks. Despite some overlap, I don't see any overall pattern that leads to concern about quality in Power Trac's electrics. I do think, however, that the machines seem to have at least a glitch or two that may cause problems if you don't have a meter handy.

 

[Charlie_Iliff]

Terry is arranging for a replacement for my broken blade, but is also going to talk to engineering about a different configuration. The light blades mounted rigidly to the stump jumper do a pretty job, but I am sure I'll keep breaking them.
I am going to try to assemble a system that uses swiveling blades like the rough cuts, but with finish type lift. I need to track down some washers, bushings, etc., and hope to hear from PT about any systems they've experimented with.
I'm starting to feel jealous of you 425 owners. Your machine is simply a better lawnmower than mine. Sure would like to have both.

 

[MossRoad]

<font color=blue>Sure would like to have both.</font color=blue>

Me too /w3tcompact/icons/smile.gif

I'm sure I could find some uses for the bigger machine.

 

[bubenberg]

someday soon

 

[davesisk]

He he...I'll trade ya even for my 1418! /w3tcompact/icons/smile.gif

Dave

 

[Charlie_Iliff]

<font color=red>I'll trade ya even for my 1418</font color=red>

Dave: I appreciate the offer. but I'm just getting used to the 1845. Where but on TBN can I find such generous fellows. /w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif

 

[bubenberg]

ready for nomination to the position of secretary of state!!!!!

 

[Charlie_Iliff]

I learn from my mistakes -- I can repeat them exactly. Ever tell someone on the phone to send some stuff and charge it to your account or credit card, then hang up realizing you hadn't confirmed the cost?
The rough cut blades on the 72" deck swing on 5/8 bolts. There is a 5/8 to 1" bushing, .41" long, around the bolt, so the bolt can be run down tight and the 3/8 thick blade has a 1" hole so it can swing free. I called Don and told him to send me 16 of the bushings to use in experiments with various finish foil blades. Figured they'd be about a dollar each. They came today, complete with packing slip -- $5.85 per bushing. I assume they're also used for internal spacing on 80,000 rpm gas turbines.
My fault, of course, but I have to decide whether to send them back and hunt around for replacements.
Some Power Trac parts aren't bargains.