Author Topic: Model Woodsplitter  (Read 19899 times)

Online Johnmcc69

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Re: Model Woodsplitter
« Reply #30 on: January 31, 2015, 06:24:20 PM »
Brian, how will the rack be returned to the "open" splitting position? I see you mentioned return springs, but what allows the rack to move upwards to clear the pinion? Is the "pusher" able to rotate or move upwards to disengage?

 John

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #31 on: January 31, 2015, 08:44:25 PM »
Yow!!! I'm glad there are only a couple of links. This is too much like jewellry making for me!!!

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #32 on: January 31, 2015, 08:46:35 PM »
Brian, how will the rack be returned to the "open" splitting position? I see you mentioned return springs, but what allows the rack to move upwards to clear the pinion? Is the "pusher" able to rotate or move upwards to disengage?

 John
John--You have to watch the video in post #9---I am trying to make mine exactly like that.--Yes, it does pivot up.

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #33 on: February 01, 2015, 05:21:40 PM »
This is just so NEAT!!! I didn't really trust my layout, and didn't want to make the rather complex bearing support plates until I had actually built and checked the pivot points for my linkage mechanism.
I layed out the position of the pivot holes in a scrap piece of plate and loctited the pivot shafts into place, as well as one extra round piece to act as the "travel limiter" which will be adjustable in the finished version. When the handle is pushed to the right in the "engaged" position, the two router bearings are riding against the back side of the rack and holding it in contact with the rotating pinion gear which sets below it. As I had planned it, the linkage is a "cam over" action, and in the position shown, no amount of upward force on the rollers can make the linkage move into the "disengaged' position.
   When the handle is moved to the left, into the "disengaged" position, the rollers lift up about 1/8" from the back of the rack.---The rack will be spring loaded from below to move into the "up" position against the underside of the rollers. That is the amount it needs to move to disengage the teeth of the rack from the pinion gear, so that the rack and "pusher plate" can be pulled back into the load position by a pair of tension springs attached to it. Note that in my "disengaged" arrangement I haven't moved the rack up, so you can see the gap between the back of the rack and the rollers. In normal operation, that gap will never be there---the rack always stays in contact with the rollers.



Offline Roger B

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Re: Model Woodsplitter
« Reply #34 on: February 01, 2015, 06:20:23 PM »
 :ThumbsUp:   :ThumbsUp:
Best regards

Roger

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #35 on: February 01, 2015, 08:59:36 PM »
This is what it looks like when the rack is disengaged and fully retracted. the rack and all that it is attached to pivots on the right hand lower edge of the red pusher plate, and is pushed up into that position by the grey leaf spring, which slides along the top of the main body. the blue adjusting block with the red bolt through it acts as a stop for the bottom link so it doesn't go too far back. I will probably have to turn some off the diameter of the head of the adjusting bolt for clearance from the back of the rack.

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #36 on: February 01, 2015, 09:23:19 PM »
The only thing I'm not 100% sure of is that there is a bit of voodoo going on at the "free" end of the rack. In the video, the free end of the rack has a sharp angle cut on it. I know why--the entire handle is held in the "cammed over" forward position by the grey leaf spring pushing up on the rack. As the rack gets very close to the end of its stroke, the flat leaf spring pushes the angled part of the rack up against the rollers, forcing the entire linkage to flip over into the "uncammed "retract" position and let the rack jump up out of contact with the pinion gear. I may have to figure that angled cut on the end of the rack out after I get everything assembled.

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #37 on: February 03, 2015, 12:28:53 AM »
 I had a nice peaceful morning, and found a scrap of bronze to machine the adjusting bolt holder from. Then I went down town to my steel suppliers and bought all the material to finish the woodsplitter. I decided the main body should be made of cold rolled steel because of the pusher sliding along it. I bought the correct size piece, squared it up, then cut the big notch in it, and almost immediately I realized I had cut the damned notch 1/2" too long!!! I continued on, tapping 10 holes and wondering how I could have done such a stupid thing. when I was finished on the mill, I made up a piece slightly larger than the area I had cut away in error, V-d the edges, and took it out into my main garage to my "stupid mistake undoer" (some people call it a mig welder)and welded the piece back in. Then some clean up on the mill, and nobody knows about it but me!!!

Offline Art K

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Re: Model Woodsplitter
« Reply #38 on: February 03, 2015, 03:33:13 AM »
Brian,
You know what they say sh!t happens, :wallbang: at least you had the mistake undoer.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline b.lindsey

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Re: Model Woodsplitter
« Reply #39 on: February 03, 2015, 12:15:15 PM »
Then some clean up on the mill, and nobody knows about it but me!!!


And of course we would never tell a soul Brian  ;)

Bill

Offline Alan Haisley

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Re: Model Woodsplitter
« Reply #40 on: February 03, 2015, 03:36:05 PM »
Brian,
How does this model's ram force compare with your estimate of that of the full sized version? It seems to me that the stored rotary force won't scale well and you may need some kind of fudge to get the ram to work with anything beyond balsa wood.
Does your CAD software allow kinetic analysis of this kind of issue? If so, how do the numbers work out?
Alan
Near Raleigh, NC, USA

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #41 on: February 03, 2015, 04:48:57 PM »
Alan--It's a best guess kind of thing. I don't have any supporting math.--Then again--I wasn't planning on splitting any elm or hickory!!-Brian

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #42 on: February 03, 2015, 06:53:49 PM »
That's enough silly work for today. Everything fits so far. There are some interesting set-ups in that splitter head!!


Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #43 on: February 04, 2015, 04:39:13 PM »
Well Dang!!! Ya gotta just love that!!! I just got some real work in so will have to discontinue for now.

Online Brian Rupnow

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Re: Model Woodsplitter
« Reply #44 on: February 05, 2015, 04:39:12 PM »
Now, if I just had 12 teeth cut on this baby, the pinion gear/driveshaft would be finished. The gear is so small in diameter that I didn't even think of making it a separate piece. I agonized over whether to make it out of cold rolled steel, 01 drill rod unhardened, or 4140 steel, because I am worried about the teeth shearing off. This morning I decided to go the cheapest route first, because I already had some 5/8" diameter cold rolled, and I am afraid of cutting any material harder than cold rolled steel because I don't want to wreck my smallest gear cutter. They cost me close to $70 each!! I may get the teeth cut this afternoon.