Building an Inertia/Kinetic Splitter
- Thread starter bower4311
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bower4311
ArboristSite Operative
I thought I saw it somewhere. I guess not. I'm trying to do this as safe as possible. I just get nervous about spinning wheels is all. I would prefer to have a more stable/consistent item, one that is identical to the other. I know that you would have to find two identical flywheels ideally from vehicles.
Like I said above, safety is a big concern for me, especially with a lack of experience with machining. There were certain areas I said I would not try to cut costs from and flywheels were one. But, now you guys got me thinking about other ways I could go about this and that getting those parts machined could be more expensive than I think.
How many parts do you have any what are you basing your build off of?
nathon918
Addicted to ArboristSite
if you cant find flywheels, the cheapest way is probably to find someone with a burn table to cut you some discs out of heavy plate, then have a machine shop turn them true, and drill holes for a flange mount ...
like i told you from the begining of this post, theres a reason why the super split is expensive, its the machine work.
also id do some more research on the rack and pinion material. im thinking some tool steel, maybe H13, 4140 etc. wouldnt want to strip the rack or pinion on the first split...
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Automotive flywheels would work but they are too small diameter and don't weigh enough. North1, I understand you used some diesel flywheels off a semitruck? Whats the size,weight,and OEM application of those flywheels? I checked around and they aren't cheap, but never found any scrap ones either.
bower4311
ArboristSite Operative
That's a good idea. I could try to find some used plates on craigslist or something.
bower4311
ArboristSite Operative
Cmccul8146 gave the exact parts that he used for his rack and pinion and he didn't report any problems with them. He's a machinist by trade if I remember correctly so I'm sure he had a good idea what he was buying when he purchased them. They are Martin parts that he used.
Just having someone cut out the circles on a burn table is one cost, not to mention the cost of the steel. In the winter of 2011-12 I made a 26" flywheel 1" thick for someone and my local good deal steel dealer qouted me $68.00 just to cut it out on there flamecutter. I bought the steel from them for around 90 some dollars and torched it out myself. Spent about 2 hours grinding down the OD to get past the flamehardened edge and spent about 2 hours machining it up and balancing it up so it ran true. After that I decided if I was to build an inertia type splitter I'd try to find some premade flywheels. I charged them $250 to make it,but it was a favor for a good friend. This is just giving you an idea of what the cost and labor would be to make flywheels,from someone that has the means and knowledge to do it.
Has far as the rack goes, I can see machining my own has I don't see any surplus ones cheap enough. Plus the gear rack and pinion gear are what I consider "wear items". So if I strip a rack out after a few hours of use, I'd only be out about $40.00 in steel and a few hours of machining compared to $345.00 that Amazon wants for the rack. I know these parts aren't heat treated but my idea would be to make the rack harder then the pinion gear. So the pinion gear would wear or strip before the rack.
bower4311
ArboristSite Operative
Yeah, I'm starting to see that the flywheels are going to get tricky to find.
I'm not sure what Paul at Super Split does but I don't remember anyone ever mentioning replacing those items. Now, he does have his machine down to a science and I'm sure it has very little stress compared to homemade but if he does some sort of heat treating that would be nice to know. Maybe someone has talked to him about it. How much does heat treating run and who can usually do it?
Wouldn't big machine shops have wholesalers that could get you a rack and pinion for a reasonable price?
I'm not sure what Paul at Super Split does but I don't remember anyone ever mentioning replacing those items. Now, he does have his machine down to a science and I'm sure it has very little stress compared to homemade but if he does some sort of heat treating that would be nice to know. Maybe someone has talked to him about it. How much does heat treating run and who can usually do it?
Wouldn't big machine shops have wholesalers that could get you a rack and pinion for a reasonable price?
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bower4311
ArboristSite Operative
Motion Industries has almost the same rack that Cmccul8146 used, 14.5 degree vs 20 degree which I couldn't find but I'm sure they can get it, for around $200. Seems they have a lot of locations around. I would assume they won't charge for delivery to a location and I don't see if they have minimum orders or if they handle retail or whatnot. I'm not familiar with the company but I may give them a call.
EDIT: $100 for the spur gear
EDIT: $100 for the spur gear
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I deal with Motion Industries in my town. They are a little on the high side for things. They have no minimum and I always do my homework before going there. McMasterCarr also has these rack gears at not a bad price. Around $200 still seems to expensive for something that can be junk in seconds with the pull of a handle. Supersplit does have these splitters dialed in. I bet he sources his flywheels over seas to his specs. Not much can go wrong there. I think his racks are off the shelve part, but I think he machines the pinion teeth onto the flywheel shaft.
bower4311
ArboristSite Operative
Very true. But I think it is a risk I am willing to take, since if I do go ahead I have no choice anyway.
It would only make sense to machine the pinion teeth into the shaft if you're in the business. Any idea what that would cost to get done if it would be worth it at all?
Do you know anything about heat treating?
nathon918
Addicted to ArboristSite
unless you can find someone that mass produces fly wheels, theyre going to be expensive, you could have some cast but theres still machine work involved.
as for making a rack and pinion unless you have gear making equipment (gear hobs, CNC mills, grinders,etc) its going to take alot longer then "a few hours" to make a 24"+ rack and pinion!
nathon918
Addicted to ArboristSite
theres also Eastern Industrial Automation, theyre a new england company, all power transmission, motion control, components...
bower4311
ArboristSite Operative
Thanks, doesn't look like they have anything close-by to me. If I do it, I'll go with the 2' rack and have an extension attached if this is possible. Someone stated in the other thread that they thought it would work. I also don't need it to split anything longer than 20 inch. But that could be used for a trial and if it's too short I'll just spend the money for the 4' rack.
Heat treating is a mystical art in itself. Alot of variables and it all depends on what type of steel you start with and what dimentions the final part has to hold. What I was getting at was I was thinking about machining the rack out of a harder steel then the pinion.Heck, the pinion could be also made from brass.
A 24" rack would be easy. I could order the correct cutter profile and use my veritcal mill with digital readout or I could grind the cutter out of a piece of high steel tool blank and use my prehistoric metal shaper (my perfered way). The first one always takes the longest,any after that seem to go faster because you already have the setup and cutter made.
bower4311
ArboristSite Operative
Right. Well, I think that I will look into heat treating of gear racks and pinions. Find some more information. If it's worth it, why not, who wants to risk breaking a $200 part.
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#99lb each
#19 inch wide
OEM application???
# I paid them $ 100 # they are from the same type track
gear #is that T 16961 16 http://www.ideal-velenje.si/pdf,cdr/str_el_2/03-Celni_zobniki.pdf
#they cost me 20$#
rack consists of two narrow pieces that are fitted to flat iron 2.5x 0.8
rack and I beam faund on scrap jard for free
http://www.arboristsite.com/firewood-heating-wood-burning-equipment/111335-10.htm
OEM means Original Equipment Manufactorer or what did it come off and what was it used for?
Now that we have hashed over some of the issues with sourcing parts for the build, lets talk about some of the engineering issues with the design on this splitter. Seems the biggest problem to having a successful inertia splitter is the engaging of the pinion gear to the rackgear. In my opinion these parts are miss used. They are not designed to be engaged while they are running with the momentom of 2 70lb flywheels driving the pinion. Superslit,Cmccul18146, and Larry Barnett have seemed have it down by having the pinion gear turning less then 200 rpm. This makes the sudden engagment not has much of a strain on the teeth of the pinion and rack gear. This is where Speeco went wrong with there inertia splitter. Larry Barnett has took the design one step further by having the flywheel turning faster then the pinion gear shaft (slower rack speed more momentum from the flywheel). Has also has the slowest moving rack I've seen witch makes it less scary to operate. It kind of just pushes the wood instead of slamming the wood into the wedge. I've had thoughts about somehow designing it so the pinion gear and the rackgear were always engaged. Then clutch the pinion shaft somehow. I was thinking of a lawn tractor electric pto clutch. i think it could work. It would take all the stress off the pinion gear and the rackgear. Just my thoughts.
