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Re: historic hewing questionnaire [Re: northern hewer] #33256 11/13/15 02:56 AM
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northern hewer Offline OP
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hello everyone tonight

Now back to the bearing---

Lets get one thing straight before we go any farther-- the pitman at this point is not in the mill but still in the workshop, having been previously shaped for size and length from previous calculations, in the case of a restoration it usually means transferring measurements from an original part, at times this is not easy because of wear and breakage,or rot causing the part to disappear , and would need extensive research to bring to light what the new part's historical dimensions and appearance were--there is some caution here because what one does in a restoration will be regarded as accuracy in subsequent restorations down the line, so be careful!!

Well we have the bearing slid into the opening in the pitman, and now to fasten it in place

Previous to this point it is understood that the new bearing has been tried on the pin of the offset crank in the mill and will fit when the pitman is finally inserted in it proper position

fastening it in position is as follows--the bottom section is held secure by boring though the metal band encasing the bottom of the pitman two 3\8ths" holes from side to side, passing through the bottom section of the bearing, missing its metal band--the 1\8 by 1.25 previously mentioned-- then 2---3\8" carriage bolts are inserted and drew up snuggly, tapped slightly with a hammer as tightening is finalized--these bolts then have any excess threads removed and the peaned lightly to ensure that the nuts will not loosen due to vibration and other possible reasons

Now as we look at the pitman with its new bearing in place we will notice excess space from the top of the bearing to the top of the mortise cut out in the pit man--this is for a reason--passing through the pitman at this point is a long slender wood wedge that as it is driven through will tighten down the top section of the bearing very tightly and then secured in place

The sticker here is the direction of the wood wedge and some other interesting tidbits--to be discussed

enjoy

NH

Re: historic hewing questionnaire [Re: northern hewer] #33259 11/14/15 11:31 PM
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Dave Shepard Offline
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Was white oak the wood of choice due to rot resistance? I know hard maple and beech are often used as bearing materials in friendlier environments.


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Re: historic hewing questionnaire [Re: northern hewer] #33260 11/15/15 02:31 AM
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northern hewer Offline OP
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hello everyone tonight

Hello Dave

Thanks for coming on board, and good question

Well this is my take on it--White Oak in this case is my preferred type of wood to use--it doesn't mind the wet environment, in fact water and oak work good together, water seems to lubricate it, and seems to last a really long time before replacement is necessary

Hard maple and Beach--both good bearing material--hard maple in my mind is the superior one--gets real glassy when used for a dry area bearing it is important that you overheat it a bit by tightening it down and lots of lubrication until you can notice a little heat being generated-- then loosen back until it runs cool--great for line bearings in most mills when a babbeted bearing is not available--of course this type is superior to wood, our woollen and grist mill at UCV has all babbet bearings, with some brass bearings mixed in

the 1867 vertical blade saw mill is another animal so to speak--seemingly very crude at first glance, but in reality quite a complicated machine--we will discuss some of these features as we move along

enjoy

NH

Re: historic hewing questionnaire [Re: northern hewer] #33263 11/16/15 06:16 PM
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Hello Richard, I've really been enjoying your talk on the mill. Trying to picture it, I went online to see what else was out there. A picture says a thousand...and all that. Well, I found a link to a working sash mill in Connecticut. A little different than what you're talking about, but what caught my eye was a glossary of terms on this website. The thing that interested me most was their definition of "pitman":
" The connection from the crank on the waterwheel or flywheel to the saw frame. Analogous to the literal “pit man” on the bottom of a two man pit saw crew."
When the old Northwest Territories...Ohio...where I live, was settled, the first construction was carried out by New Englanders pit sawing timbers to build their fort and dwellings. Being the "pit man" was an unpleasant job, you were continually showered by sawdust and shavings. Anyway, I've used the term pitman all my life. That's what drives the cutter bar on a tractor when we're making hay, for instance. Never knew where the term came from. And wouldn't, had not Richard brought this whole subject up. Ripples on a pond, friends. Ripples on a pond.

Re: historic hewing questionnaire [Re: northern hewer] #33264 11/16/15 11:31 PM
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Re: historic hewing questionnaire [Re: northern hewer] #33267 11/17/15 04:01 AM
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Jim Rogers Online Confused
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That job is where the old saying: "This jobs the pits" comes from.

Jim Rogers


Whatever you do, have fun doing it!
Re: historic hewing questionnaire [Re: northern hewer] #33271 11/18/15 03:00 AM
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northern hewer Offline OP
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hello everyone tonight

welcome to the chat room D. McBride--I really enjoyed the link spent last night looking it over--it has a nice video showing the frame saw in motion--seems to run very well

There is a similar mill in NB Canada (king's landing) I have been there and seen that mill in operation--what I noticed was the vibration and noise as the saw cut--quite a contrast to the mulay mill at UCV that runs smoother , quieter

It seems to me that there was endless variations of saw mills and their equipment, the powering source--water wheel or turbine, the saw frame and in particular the methods of saw frame movement

enjoy

NH

Re: historic hewing questionnaire [Re: northern hewer] #33282 11/21/15 02:22 AM
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hello everyone tonight

well got sidetracked as usual just too many things that are interesting to chat about--now to continue the pitman bearing

--the wooden wedge is next on the agenda--it passes through the pitman in the opposite direction from the orientation of the wood bearing--actually just above it, which means that another mortise hole has to be let into the pitman and transverses through the metal band encompassing the end of the pitman shaft as well as through the wooden segment itself.---

Now just one more thing, before you insert the wood wedge to tighten the bearing,s segments is this a flat plate needs to be fabricated unless the old one is at hand, this flat plate is shaped so that as it goes into place on top of the wood bearing and will absorb the wear and tear of the friction and other extremes that will develop from the pressure of the wood wedge as it is now driven home and secured with a small nail to keep it from moving out of place

with the insertion of the wedge the lower end of the pitman now is ready for the work ahead--we will be moving to the top end next and deal with its many intricacies

enjoy

NH

Re: historic hewing questionnaire [Re: northern hewer] #33288 11/24/15 01:28 AM
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hello everyone tonight

Well to the job at hand----

let us deal alittle with the shape of the pitman itself, it slowly tapers from bottom to top, with a nice chamfering of its edges--it retains its rectangular appearance though and slowly comes to an abrupt end at the predetermined length which probably is transferred from the old worn one or if it is a completely new reconstruction, calculations will have to be made to ensure that the complete travel of the pitman in its up and down stroke fits the new elevations of the turbine box and the guide block that is located just underneath the vertical blade--this section will be discussed at length--

for now we will just say that the pitman's upper end will need to be fitted with a heavy bronze bearing in such a way that it also be able to withstand the tremendous jerking and yanking of the rotation of the turbine plus the cutting action of the blade on the down stroke

enjoy NH

Re: historic hewing questionnaire [Re: northern hewer] #33294 11/25/15 02:35 AM
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hello everyone tonight

the pitman cont'd

The upper end bearing is simpler in some ways but still has its unusual characteristics

The bearing itself is a heavy split bronze bearing that will eventually be fitted to a hardened 1" pin that anchors it tightly to the guide block

this is the way it (the bronze bearing)is anchored to the upper end of the pitman---the bearing is very near 3.5" square on its base, but the base of the bearing is not flat but has an indentation of 2" square by 1" deep, and the end of the pitman is shaped to fit snuggly up into this indentation

Now we have the base of he bearing seated on the end of the pitman--now to secure it and the upper half securely without any chance of failure

To achieve this again a heavy iron strap is forged and fitted to the graceful lines of the sides of the shaft it starts about 16" down from the upper end and encircles the lower and upper parts of the bearing finishing down an equal distance on the opposite side

I might add right here that the external surface of this bearing is shaped so that it accommodates this strap so that it (the bearing) cannot escape out sideways

Now to secure the strap

enjoy

NH

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