Converting front-mount Olathe leaf blower to rear 3pt

[dholly]

Howdy, looking for some input on a project here. Feel free to take a crack at one or more.

I picked up an Olathe model 67 leaf blower that was originally a front mount accessory for a Toro Groundsmaster, thinking it might be easy enough to mod for 3-pt hitch use. Unfortunately, it is off a 72 Series not a 52 or 62 Series, more on that later. In any event, I see some 'issues' so before I get started I figure I'd ask a couple questions. Surely someone has already done this.

Issue #1- Blower was designed to run at 1850 rpm straight off the Groundsmaster 72 front PTO shaft so I'll need to make a speed increaser. I'm leaning towards pulley and belts vs. sprocket and chain. If no arguments to the contrary, what size (width) single or dual belts would be appropriate for this application?

Issue #2 - Run blower at 540 or 960 rpm rear PTO speed? Keep in mind, my B7610 rear and mid PTOs are not independent. You can't run the mid PTO at 2500 rpm with the rear PTO being dead, and you can't run the rear PTO at 960 rpm w/o the mid PTO being live. When the lever is at the center position, both PTO's are dead. With the lever at the rear position, the rear PTO is running at 540 rpm and the mid is dead. When the lever is in the forward position, the mid PTO is running at 2500 rpm and the rear is running at 960 rpm. This will come into play if I want to mount the blower to my 3-pt hitch and use simultaneously with the belly mower. Ie., if I gear the increaser for 960 PTO speed (the only speed at the rear PTO when the belly mower is operating), in the event I just want to use the blower only it will be run at 540 PTO speed and lose almost 50% blower efficiency. While running both at once sounds good in theory, in reality do you think there's any value in the idea of dual use or just gear the increaser for 540 PTO speed and run the blower alone?

Issue #3 - Any source for (defunc) Olathe blower parts, maybe Toro Turf dealers? The Groundsmaster Series 52 and 62 mounting kit for the Olathe 67 blower is different than the mounting kit for the Groundsmaster Series 72 (pics 1 and 2 respectively). If I could find the increaser system parts used for the GM Series 52/62 it might make life easier. I believe the Olathe Model 61 blower (the Olathe factory 3-pt blower, see pic 3) also used this system. Alternatively, maybe a replacement PTO stub in pillow block bearings for the lower pulley and PTO shaft connection... ? Suggestions welcomed.

Issue #4 - Replacement bearings. Best I can tell the main bearings are Hub City FB250x1-1/4 four bolt flange bearings. There's a manufacturer cross reference on their website however, not being a bearing aficionado, it did little more than confuse me. Does any particular replacement bearing maker (for quality) and source (best pricing) come recommended? Might need to pick up some pillow block bearings too as mentioned in the previous paragraph, best to source together for shipping I suspect.

Issue #5 - Wheels front or behind? As it was, wheels were in front (pic 4) but they will be in back on the 3-pt and I wonder if the lower front edge of the housing will now catch and gouge on uneven terrain? Would you cut 'em off and reweld to the front or leave as is and add a roller to the front edge? Or not even bother.

Well that's enough for now, off to tear it down and clean things up. I think I have some Kubota orange somewhere in the paint box to use up. :thumbsup:

 

[dholly]

Disassembled the blower, scraped off about 20lbs of grease and gave everything a gas bath. Several hours later, man what a miserable job! Removing the old PTO adapter took a lot of heat. it was glued on with some kind of super epoxy. Cut off the un-necessary Toro Groundsmaster mounting apparatus and fixed a few cracks in the front and back housings. Used my last piiece of box channel left over from a trailer project to make the lower 3pt arms and drive shaft bearing mounts. Got the lower arm assembly stuck to the blower casing and prepped everything for some fresh paint. Felt like good progress today.

 

[dholly]

The bearing seals were shot but the flange blocks are fine, so I called Hub City for the replacement B250x1-1/4" bearing inserts. Surprise, they have been on back order for over three months with no ETA. They did show four complete flange block units in CA somewhere, but with shipping to the other coast they wanted an arm and two legs so I passed. A few more calls and I was beginning to wonder if that was a good move. These and any US mfg cross inserts are pretty darn scare for whatever reason. I ended up finding a local shop that sold complete import units for less than half the price of the inserts. Two flange bearings for the fan shaft and two 1-3/8" pillow block bearings for the drive shaft cost $60 with tax. The old tires were flat and the original wheel bearings were completely missing, so another $20 for two new tires, wheels, axles and spacers. I only have about a quart of orange left so I sprayed everything with a couple coats of safety yellow Rustoleum as a primer. Bought 10 quarts for $0.50 each off the return rack at HD years ago when I needed to paint a snowplow blade and been trying to use up the leftover 9-1/2 quarts ever since.

 

[dholly]

Got it back together and started on the top link. Was going to add a solid upright post between upper and lower arms but now think I'd be better off letting it float, any thoughts?

Got a lead on a used PTO shaft to cut down but no dice at the local scrap yards for a 6-spline end jack shaft. Trying dealers for broken parts in their service depts but not holding my breath. Probably can find on eBay, or your suggestions for another source?

Have decided to gear the increaser off 540 pto rpm so Issues #2, 3, 4 & 5 are resolved, still working on #1. My local TSC doesn't have the right combo of sheaves or sprockets, so the speed increaser decision remains open. Not sure a 2-groove sheave will work based on space constraints, only have 1-3/8" of shaft stub length at the blower (1-1/4" shaft) and about 2-1/2" clearance from end of blower shaft to lower cross member. Single groove pulleys or sprockets and chain? Don't really want to buy 10' of chain if a single belt will work. Can get 3.05" and 10.25" single groove sheaves with the proper bore hub inserts for about $65 for the bearing shop, but that's about the best I can find. Any better options? Whats the best V-belt if I use single groove pulleys, A or B belt... or is there some kind of super heavy-duty V-belt... that might require a special pulley groove?

C'mon guys, plenty of views and I could use some experience here. Thanks in advance, the leaves are gettin' scared! :laughing:

 

[dholly]

New wheels and final color are on. Test attach shows good clearance, can still raise wheels another inch if needed. Tracks fine at mowing speed with no wobble. Got the pillow blocks and jack shaft ready for install, just waiting on some sheaves to arrive.

 

[rswyan]

C'mon guys, plenty of views and I could use some experience here.

dholly,

I had a large and fairly long reply typed up to your initial post .... but unfortunately my browser crashed, taking my reply with it.

I've been working flat-out myself trying to get the drainage and grading done on my barn before the weather gets bad (didn't shutdown the tractor until about 10:30 last night) ... otherwise I would have typed it all up again and replied.

A great project, and looks to be well executed .... I've thought about doing similar myself, and been looking that used blowers like that on Fleabay for several years now.

I'm afraid I don't have much in the way of experience to offer any advise .... on the belts though, you might want to check Gates Rubber's website on various belts and what they are rated for:

Gates Power Transmission Belts

One question/suggestion I do have is on the diverter chute for the blower output - it looks like it will drop down to divert the airflow from the (left) side to the rear[/B] .... on the unit the blower was intended to be used on, that would have been to the front instead .... which might be somewhat useful ......

I'm figuring that having it blow rearward might be less useful than say extending the chute so that dropping it down will divert the output 180 degrees - that way you could blow to either side of tractor .... I've seen this on some of these blowers .... Agrimetal maybe ?

Just a thought.

Thanks in advance, the leaves are gettin' scared! :laughing:

I'll bet they are .... :thumbsup:

 

[dholly]

Howdy rswyan-

Sorry you lost your first post, that is frustrating. Thanks for giving it a second shot with the Gates link, I learned there are quite a bit of rating differences even within the same belt type. I'm also learning there is a lot to know about bearing, sheave and belt combinations too. :confused2: This has been much harder to find a cost effective combination of parts to get the necessary 3.4:1 increase than I thought it would be. For ex., it's next to impossible to find a small, say 3"-3.5" o.d. 1-3/8" direct bore to use on a standard PTO shaft. If buying new, my best option seem to be combination A/B V-belt split taper bushed sheaves for "4L" or "A" Belts and "5L" or "B" Belts. The "B" belts are much beefier and combo sheaves are not that much more expensive than the "4L" or "A" Belts only sheaves.

I still have a question about how much shaft length is required for a sheave bushing to get proper grip, ie. the thru-bore measure for a large dia. Browning 2BKxxx (2-groove) type 2 'H' bush hub is 1-3/4" vs. 1-1/2" for a BKxxx (1-groove) type 2 'H' bush hub. I only have 1-3/8" of fan shaft exposed length now, but might get another 1/4" if I can remove a little spot of weld warp on the drive side housing face and push it in a bit more before locking the bearing. I have one tiny rub when rotating the fan but was just going to let that work itself out at 1850 rpm 'cause I didn't want to split the case again.

Yes I debated about a 180* degree chute option too, the Olathe Model 61 3-pt blower actually had one (see pic). At first blush blowing backwards seemed silly, but after a little reflection I think I'll leave it as is for now. Flipping the lever to re-direct the blow straight back will allow me to pass closely next to things without having to throttle down or stop the tractor and clutch the PTO off. That may prove more valuable than the ability to blow to both sides.

 

[dholly]

Since I needed to get a measure around the sheaves for belt sizing, I mocked up a jackshaft using a shaft I had laying around and a pail lid which turned out to be almost the exact same dia. as the big sheave. Unfortunately, I got an unexpected surprise later when I picked up the shaft I intended to use. I had sourced a 1-1/4" o.d. shaft from a local recycler over the phone, but seems either the junkyard dog was confused on the request or it shrank on the way home because the axle shaft is actually just shy at 1.216". I shoulda brought my calipers with me. Oh well, live and learn, I'll survive the $2 hit to my wallet and keep it for another project. Anyhow, I opted to use the 1-1/4" round shaft because finding a cheap 1-3/8" shaft with 6-spline end was proving difficult and PTO shafts for post hole diggers have a 1-1/4" round implement end. Figured I could cut one of those down or change out the yoke on a standard PTO shaft. Now it looks like the jackshaft hunt is back on or, if I can find a 1" or 1-1/8" round to 1-3/8 6-sp PTO adapter floating around somewhere, maybe I'll check to see what it would cost to turn down either of the two shafts I have. I don't like this drama and want to get to blowin', the leaves are getting thick and I think they are starting to chuckle behind my back.

 

[dholly]

Picked up the sheaves, bushings and belts today. Decided to use 2-groove sheaves, a Browning 2BK32H 3.35" o.d. for the jackshaft and a 12.75" o.d. Maska import for the fan shaft. Besides being w-a-y less expensive than the Browning 2BK130H, the Maska has a reversible hub bushing which I felt might come in handy for clearance issues. The hub bushing is also more substantial vs. the Browning type H bushing, and this was recommended specifically due to having to grab onto a shaft stub whose length was less than the bushing thru-bore.

While I needed a 3.43:1 increase ratio (1850 rpm mfr operating speed / 540 PTO speed), these sheaves provide a 3.81:1 increase. That means at 540 pto rpm the fan will run at 2057 rpm, approx. 11% over the blower mfr's operating speed. Not too worried about that, it's under the max 2100 rpm stamped on the Maska sheave, the fan flange bearings are rated much higher, plus the fan and casing are heavy duty built like a brick s#!t house. Since 540 pto speed is achieved at 2600 engine rpm on my tractor, running at 2300 rpm should provide the blower speed necessary with a bit of fuel economy. That's the theory anyway, sounded pretty good on paper.

Also purchased two Browning BX GripNotch V-Belts which "have a fabric top and bottom to increase rigidity and stability of the belt, and ground form raw edge sidewalls for a uniform, anti-slip surface with greater flexibility, reduced vibration and increased belt and bearing life." I hope so, they come at a premium. And, I finally just bought 2' of 1-1/4" round stock with a 5/16" keyway to use as a jackshaft and returned the pillow block bearings for the correct bore. Should have just done this earlier but I was worried because the tapered bushing hub for the small sheave had a 1/4" keyway and key. Actually not problem, they have 'stepped' keys for just such a situation I learned today.

 

[dholly]

Existing clearance says I can mount the big sheave either Standard (hub bushing on first) or Reversed (hub bushing last).

Given that the 1-3/8" fan shaft is shorter than the hub thru-bore, do you see any preference or benefit to Standard or Reverse mounting in my application?