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Re: historic hewing questionnaire [Re: northern hewer] #21049 09/01/09 01:21 PM
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Jim Rogers Offline
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Originally Posted By: northern hewer

Well I finally made it back on, I don't know about all you guys and gals out there but I have been having a rough time signing in sometimes it is pretty near impossible.
NH


NH, don't log out..... just close your browser and next time you enter the forum you should be logged in....
This works for me, but I'm unsure if it will work for you....

Jim Rogers


Whatever you do, have fun doing it!
Re: historic hewing questionnaire [Re: northern hewer] #21052 09/01/09 02:02 PM
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Originally Posted By: northern hewer
HI everyone tonight:

I don't know about all you guys and gals out there but I have been having a rough time signing in sometimes it is pretty near impossible.

NH


Hi NH,

Try this as another fix to your logging-in issue:
At the top of this page, click on "My Stuff"
Select "Cookies"
Click the button labeled "Expire Cookies"

It says "Expiring (deleting) the cookies set in your browser by this board may be useful if you suspect that they are damaged or the board is malfunctioning for you."

I'm enjoying the mill discussion. Great stuff, especially the scarfing and the 24 x 24 purpleheart timber shaft.

Ken when this project "winds" down maybe you can post some pictures of all this.


Don Perkins
Member, TFG


to know the trees...


Re: historic hewing questionnaire [Re: OurBarns1] #21058 09/01/09 10:24 PM
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TIMBEAL Offline
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It would be nice to see. Some video as well, maybe.

I cleared my cookies out and it fixed the problem.

Tim

Re: historic hewing questionnaire [Re: TIMBEAL] #21187 09/18/09 12:46 AM
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northern hewer Offline OP
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Well Hello everyone tonight:

I just was able to get loged in for the first time tonight, it has been quite a struggle for the last week or so. I just thought that I would try it to see if it would work as I was starting to give up and lo and behold it worked, nice to be back with everyone again.

I would like to thank Ken for the posting that explained the main cane crushing component of the Barbados Mill--way back on the 2nd of the month, it sure was appreciated, and I am sure many members that passed by this site stand in awe of the millwrighting that must have gone into the construction of these mills.

One question that I have for you Ken---

-- what kind of a braking system could handle such a monstrous piece of equipment which in case of an emergency could stop and hold the mill's sails idle through high wind disturbances?

I know from experience that the slow revolving sails would create an immense tourque, and in turn would require a specialized braking system along with very heavy gearing

Thanks again Ken
NH

Re: historic hewing questionnaire [Re: northern hewer] #21189 09/18/09 07:20 AM
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Ken Hume Offline
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Hi Richard,

This may come as a surprise to some as it did to me but there is no braking system. Should there be a need to slow the mill down then the cap would be rotated out of facing directly into the wind and then the cane crushing rollers would be loaded up to slow the mill down eventually with the cane causing the mill to stop. The sails can then be turned backwards manually using ropes secured to the ends of the sails, the rolls cleared and then the sails tied off and secured to horizontal posts built into the lower part of the mill wall.

This is not exactly a very safe system of working and at first sight this would certainly not meet today's health and safety at work (OSHWA ?) standards but a delicate balance of weight and force (torque) is going on in the cap and the introduction of braking forces might well result in unexpected consequences.

Regards

Ken Hume


Looking back to see the way ahead !
Re: historic hewing questionnaire [Re: Ken Hume] #21197 09/19/09 10:39 PM
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Jim Rogers Offline
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I once asked an older sawyer how the would start and stop a water powered mill, in case of some need such as service the blade.
And I asked what kind of "clutch" was used to disengage the arbor.....

You can't imagine the look he gave me......

And he simply stated, you "stop the water......."

It seems that most mills that he was familiar with had some type of water way that could be opened and closed by inserting or removing some short planks in a chute.



Whatever you do, have fun doing it!
Re: historic hewing questionnaire [Re: Jim Rogers] #21447 10/20/09 12:55 AM
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northern hewer Offline OP
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Well hello everyone:

Thanks to Mr. Ken Hume who put in a help call for me--- once again I am able to access this chat room, it has been 1 month since I have been able to come on board with all my friends from around the globe--it feels really good for sure!

I have been looking at the last post from Jim in regards to an explanation about starting and stopping a muley mill, well here we go--------

To start things off jim, you must understand that the muley blade is tethered to the crank fastened on the end of a 12" oak axle which in turn extends through the centre of the horizontal water barrel.

The tethering is via a large heavy oak pitman that in turn pushes upwards and downward as the axle rotates, this rotation can reach up to 125 rpms with 80 or 90 being a normal speed one at which the machinery is designed to run and run and run with very little maintenance whatever.

Now to answer your question---

You can see there is no clutch between the power source and the vertical blade, so to stop the mill the method that our 1858 mill was designed to use was as follows.--

At the end of the head race and in line with the water barrel directly below the blade there is an opening in the end wall of the head race of approx 24" by 36". On the inside suface of the wall along each edge of the opening are metal plates securely fastened. Against these plates slides a door (vertically) also with metal plates that bear against the ones on the wall. This door has fastened to it a heavy upright stem of oak (2 by 6) which reaches well above the raceway walls. fastened to this upright and cantilevered over a fulcrum is another rather heavy horizontal oak 2by 9 which is long enough to reach the exterior wall of the mill, now the tricky part is that this fulcrum has to be placed at the point that the weight of the 2 by9 should balance the weight of the door and vertical stem, but not quite.

Along the wall (on the upper level)extending down to the end of the 2by9 is a round pole that the sawyer can pull up on or shove down on depending on whether he wants to start or stop the mill.

This system works really well and I will explain.

To start the mill the sawyer shoves down and instantly opens up the gate fully allowing an inital thrust of water to hit the inside of the barrel wheel, this gives the equipment the power it needs to lift the pitman and the blade to the top of its first stroke, then the revolving motion with the momentum of the weight of the pitman the blade the 12" oak shaft, and the large cast collars gives the saw blade a smooth motion with the equipment acting like a flywheel so to speak.

To sort of end this discussion for tonight I will add that the sawyer can at his own discression slow down or speed up the mill with a gentle pull up or shove down on the pole by his side

This mill uses about 2000 gals of water per minute at full throttle

hope you all enjoy this little chat please ask any question and I will try and answer them to te best of my ability.

NH

Re: historic hewing questionnaire [Re: northern hewer] #21448 10/20/09 02:47 AM
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Jim Rogers Offline
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Thanks for the explanation of how that mill works....


Whatever you do, have fun doing it!
Re: historic hewing questionnaire [Re: Jim Rogers] #21465 10/21/09 02:26 AM
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northern hewer Offline OP
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Hi everyone tonight

You are entirely welcome JIm, it is questions and interest from people like you that makes my day, and I hope that those that stop by can understand some of the mill technology from years gone by.

Our mill as it operates today uses a barrel wheel, or as some prefer to call it a Rose Wheel, there are pictures of it in past posts on this very chat site, itmay take alittle looking around to find them, but you might just run across some other tidbits that are quite interesting that deal with many other subjects, including the original one hewing timber by hand with a broadaxe, this in itself is quite a varied subject depending on who you are talking to, and what part of the globe you are from.

The term Rose Wheel I expect is derived from the cast iron collars on each sideof the Barrel Wheel's box, These collars fit on tapered surfaces on the 12" oak shaft and rotate with the shaft at about 1\4" clearance from the sides of the box creating a pressurized interior cavity. One of the main enemies of this set up is believe it or not a single square nail, if one happens to work its way along the head race and enters the pressurized area on its way out it could get lodged between the collar and the wooden oak box, 1\4" being just the right gap for it to enter and hang by its head. If this happens it is very difficult to remove, and will stop the mill dead in its tracks.

To get back to the term Rose Wheel, the cast iron collars referred to above have multiple cups casted into each one in such a way to give it an appearance of rose pedals.

One interesting feature about these collars is that the 2 of them are like a reflection in a mirror and applied on each side of the Box gives thrust in the same direction.

The produced power from our setup at UCV with an 8 foot head of water and at full throttle is about 6 horsepower, which does not seem like much in our world but remember whatI said above once you have the whole setup revolving say at 80 rpm it is developing far more power than that simply because of the mass of all the revolving parts, including the force of the water. At full throttle 2000 gals or approx 10 tons of water is forcing its way into the pressurized cavity every minute, and then trying to find its way out, that is when you capture useful energy to work with.


I have had course to measure the horsepower at full throttle (125 rpm) with the machinery revolving and I estimate that for brief periods you could have 20 horsepower of useful (smooth)energy.

I hope that you enjoy

NH

Re: historic hewing questionnaire [Re: northern hewer] #21467 10/21/09 07:20 AM
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Hi Richard,

Your power estimates are of interest to me.

In simple terms power = torque x rotational speed and this does not necessarily follow a linear relationship i.e. if the speed doubles but the developed torque say halves then the power produced is the same as before. I wonder if your power testing managed to develop a set of Power / Torque versus speed curves for the mill. This might have helped established the optimum speed at which the mill should run when in production.

6HP is not so different from that provided to a small portable band saw and so this sawmill should be able to do some useful work. What happened when the saw got to the end of its travel and hence had finished absorbing the power produced by the water wheel. Was there a general speed up in the reciprocation of the saw or did you have a flywheel momentum storage device to help smooth out power demand fluctuations ?

Regards

Ken Hume

Last edited by Ken Hume; 10/21/09 07:21 AM.

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