# Tool Talk >  Panzer tank hull being quenched

## Jon

Gorgeous photograph of a tank hull being quenched. Internet chatter indicates that this is a Swiss Panzer tank from around the '60s or '70s. Beautiful enough to justify printing and framing for formal display, in house or shop.



Previously:

tank silencer
steam-powered tanks
Tankenstein rat rod
Big Wind firefighting jet tank
WWII Churchill tank converted into mine clearer

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Altair (Jan 15, 2019),

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Inner (Jul 30, 2017),

KustomsbyKent (Jul 30, 2017),

Marc Broussard (Jul 31, 2017),

mwmkravchenko (Sep 6, 2019),

NortonDommi (Jul 30, 2017),

Priemsy (Jul 30, 2017),

saintrain (Dec 8, 2018),

Seedtick (Jul 31, 2017),

TheElderBrother (Nov 19, 2020),

Toolmaker51 (Jul 31, 2017),

Tule (Jul 31, 2017),

will52100 (Sep 1, 2017)

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## Mikebr5

No kidding... That is beautiful I didn't know that such quenching was done. 
Big industry is amazing and wonderful.

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## 3990918

Hellova a lot bigger than a Ngombe Ngulu blade...lol

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## Frank S

I was thinking about the shear enormity of the furnace to heat up that much mass probably have to be fed by a 24" or larger gas main maybe several

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## Marc Broussard

Don't try this at home. Wife will have bigly issues. LOL. I wonder if this is still getting done. Here in America maybe? A whole tank?

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## Toolmaker51

Print and Frame, and jpeg; exactly what I will do.
I collect examples that indicate what a manufacturing economy is all about. 
And a few that indicate the narrow impact of a service economy.

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Marc Broussard (Jul 31, 2017)

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## Frank S

> Print and Frame, and jpeg; exactly what I will do.
> I collect examples that indicate what a manufacturing economy is all about. 
> And a few that indicate the narrow impact of a service economy.



I save a lot of these unique photos of manufacturing processes especially the ones from an eara when it would have been thought impossible to accomplish.

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## Toolmaker51

> I save a lot of these unique photos of manufacturing processes especially the ones from an eara when it would have been thought impossible to accomplish.



Frank, I agree wholeheartedly. My favorites are the WWII era ads from Fortune and Life magazines, featuring American manufacturing supporting the war effort.
In my own short life I recall when impossible was just a term, the perspective was difficult or a challenge. Intuition, judgement of options, testing, and adding 10% margins solved many projects.
Impossible to accomplish wasn't known until professional engineers and digital designwork collided with centuries of fit, form, and function, initiated by sliderules and notepads. 
Egyptian Pyramids. Hoover Dam. Small Block Chevy. Tennessee Valley Authority. Model T. Wright Brothers Flyer. Golden Gate Bridge (nearly any bridge for that matter, including Iron Bridge in England...) Aircraft and radial engines built before the 60's. V Twin Harley-Davidson's...need I continue? 
Some not so successful, because 'certified' engineers & accountants got into the act of design; The Titanic, Galaxy Note 7, (google 'design failures for plenty more). The Titanic is rather unfairly judged, unsealed compartmentalization notwithstanding. The failure is not of the ship so much, as the rhumbline courses it was ill designed for.

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## Frank S

I used to have a little saying on a plaque that sat on my desk . 
" I f anyone else could do it why did you bring it to us? Here we only focus on the impossible, which is usually done imeadiatly. The difficult will be done according to regular scheduling . The simple should be redesigned prior to submittal ,and the easy will be re evaluated and modified before farming out.
We only want your business not your busyness"

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## Saltfever

Interesting! Consider the weight of the whole tank. Then it is being suspended by 4 chains (that are also being heated and weakened!) attached to 4 stubs that have been heated and lost strength. Timing of this operation is non-trivial.

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## Frank S

While the weight of the tank frame is significant it is only about 1/4 of the total tanks empty tactical weight. the 4 stubs would most likely be considered expendable then probably removed during the machining process 
The 4 chains would not have been in the furnace with the tank and would only receive heat radiating from the mass 
Visiting a large foundry such as that one would be a great bucket list item. I've been to smaller ones and a couple of steel mills 
The one I would really like to visit is the Hyundai

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## Saltfever

The point I am making is the steel is at red heat. I didn't look it up but steel has probably lost 60%-80% of its tensile strength at that temp. The chains are in direct contact and are getting weaker by the minute. Obviously all accounted for; but someone was watching the clock . . . or the color of the chains!  :Smile: 

BTW, heat is being *conducted* directly into the chains by the stubs!

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## Frank S

I know what you are saying about someone watching the clock. or accounting for the amount of time elapsed from initial opening of the oven hooking the chains and dunking the mass in the quenching vat. the watching the clock in this case I imagine would be metaphorically speaking.
Once as a kid in the blacksmith shop where I worked I picked up a pair of tongs a little to close to the business end I immediately dropped them in the quench tank the Blacksmith asked what's the matter son were they too hot for you? 
Nope it just didn't take me long to look at them.

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Toolmaker51 (Oct 26, 2018)

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## buck

> I was thinking about the shear enormity of the furnace to heat up that much mass probably have to be fed by a 24" or larger gas main maybe several



there are the furnaces behind the pic

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## buck

> Interesting! Consider the weight of the whole tank. Then it is being suspended by 4 chains (that are also being heated and weakened!) attached to 4 stubs that have been heated and lost strength. Timing of this operation is non-trivial.



that is not the whole tank, just the raw casting of the as yet unmachined tub, its still very heavy

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## Saltfever

Sorry, wrong word. Instead of "tank" it should have been "casting". Besides that it doesn't even look like the tank or tub. It appears to be the truck casting which is a part of the overall assembly and likely only a very small part of total assembled tank weight.

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## Jon

Can anyone speak to the use of casting to manufacture this tank hull, as opposed to welding or riveting/bolting? Or is this practice simply common for the tank hull, but other processes are combined to manufacture the entire tank? I'm curious about differing strengths, cost, and how different processes may have been used over the years, especially with varying military resources available in peacetime vs. wartime.

Also, here is a fullsize image version more suitable for offline reproduction:

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## Frank S

Jon I couldn't say about the Abrams but many of the US tanks and others around the world the hulls and turrets were essentially made from large steel castings many of the other large components were steel forgings. Casting the hull in one piece saves time and money not to mention is makes structurally stronger than mere welding riveting or bolting could ever achieve.
I imagine that the process of creating a single casting of that size probably required more than one crucible of molten metal then re heating it if the oven and quenching would insure good molecular adhesion and alignment

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## buck

> Jon I couldn't say about the Abrams but many of the US tanks and others around the world the hulls and turrets were essentially made from large steel castings many of the other large components were steel forgings. Casting the hull in one piece saves time and money not to mention is makes structurally stronger than mere welding riveting or bolting could ever achieve.
> I imagine that the process of creating a single casting of that size probably required more than one crucible of molten metal then re heating it if the oven and quenching would insure good molecular adhesion and alignment



that could not be a forging, it has internal cavities,, its possible many castings welded into a single piece, then heating would normalize stresses, quenching might then harden the hull/tub, that hull is upside down, there are more plates to be welded in,,the square holes showing, one of the holes would be the emergency bottom hatch buck

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## Frank S

Buck I did not mean to imply that the hull was a forging what I said was there are forgings utilized in the making of tanks. and yes the panzer could have been a welded assembly of welded parts then as you said heated to normalize and harden. The process of doing something like that bringing it to a full red color would be extremely stressing on any welded areas as rolled plate steel has a natural directional grain which cause it to expand in differing directions when heated. One reason for my belief that this is a steel casting is the lack of any fixtures jigs or braces to be seen which would be very prevalent if this were a weldement as such items are never removed prior to heat treating. otherwise the whole assembly could become misshapen to the extent of being scrap metal. 
Whereas a homogeneous casting is grain neutral even when poured by multiple crucibles as long as the plug remained at temperature. 
I was once hired or rather asked do do a favor by the owner of a company that had a contract fabricating transport fixtures for the engines that were used on one of the fighter jets For Lockheed Martian, see if I might have or be able to come up with a solution for their problem. They were experiencing a near 100% NO-GO rating on their fixtures after they returned from heat treatment. the Gov inspector would sign off on the fixture prior to heat treating for fit finish and tolerances . Upon their return he failed every one of them. some measurements would be undersized some over sized some out of dimensional squareness , parallel, angles were off, you name it if there was a possibility to be wrong they would be. then they started sending them in still in fixtures this made an improvement but still not within specs. I started noting the dependencies then I noticed a pattern of the under and over out of square and so forth so once I thought I had most of it figured out I instructed the companies engineers to spec out some new fixtures with built in adjustments plus add in some fixtures in several different places most of those could not be put in place until the weldement was completed.
After the G man signed off on the assembly to sent it out for treatment we tweaked the jigs here and there by just a little more than the final discrepancies were and added in the extra fixtures. then sent the one frame out to be treated when it returned we removed all of the fixtures prior to final inspection as was SOP 
the frame received an 80% pass which was close enough for the G man to say that it could be ground and reamed and utilized.
After that first passing grade all of their frames passed even closer to specs by the end of their contract I heard they were obtaining a near perfect pass rating 
I got a brand new 1984 Hobart Meg a arc 400 amp diesel welding machine for my troubles out of the deal

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## buck

> Buck I did not mean to imply that the hull was a forging what I said was there are forgings utilized in the making of tanks. and yes the panzer could have been a welded assembly of welded parts then as you said heated to normalize and harden. The process of doing something like that bringing it to a full red color would be extremely stressing on any welded areas as rolled plate steel has a natural directional grain which cause it to expand in differing directions when heated. One reason for my belief that this is a steel casting is the lack of any fixtures jigs or braces to be seen which would be very prevalent if this were a weldement as such items are never removed prior to heat treating. otherwise the whole assembly could become misshapen to the extent of being scrap metal. 
> Whereas a homogeneous casting is grain neutral even when poured by multiple crucibles as long as the plug remained at temperature. 
> I was once hired or rather asked do do a favor by the owner of a company that had a contract fabricating transport fixtures for the engines that were used on one of the fighter jets For Lockheed Martian, see if I might have or be able to come up with a solution for their problem. They were experiencing a near 100% NO-GO rating on their fixtures after they returned from heat treatment. the Gov inspector would sign off on the fixture prior to heat treating for fit finish and tolerances . Upon their return he failed every one of them. some measurements would be undersized some over sized some out of dimensional squareness , parallel, angles were off, you name it if there was a possibility to be wrong they would be. then they started sending them in still in fixtures this made an improvement but still not within specs. I started noting the dependencies then I noticed a pattern of the under and over out of square and so forth so once I thought I had most of it figured out I instructed the companies engineers to spec out some new fixtures with built in adjustments plus add in some fixtures in several different places most of those could not be put in place until the weldement was completed.
> After the G man signed off on the assembly to sent it out for treatment we tweaked the jigs here and there by just a little more than the final discrepancies were and added in the extra fixtures. then sent the one frame out to be treated when it returned we removed all of the fixtures prior to final inspection as was SOP 
> the frame received an 80% pass which was close enough for the G man to say that it could be ground and reamed and utilized.
> After that first passing grade all of their frames passed even closer to specs by the end of their contract I heard they were obtaining a near perfect pass rating 
> I got a brand new 1984 Hobart Meg a arc 400 amp diesel welding machine for my troubles out of the deal



not to worry,, i was just adding what little bit i felt comfortablw with observing,, buck

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## Jon

A Leopard 1 Tank cut in half.

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Seedtick (Oct 26, 2018),

Toolmaker51 (Oct 26, 2018),

volodar (Oct 27, 2018),

will52100 (Oct 26, 2018)

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## Toolmaker51

Cutaway is stupendous! 
Must of been a huge bandsaw....Not being ex-Calvary or armor, I can only reason out a portion of components. Anyone aware of a labeled view?

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PJs (Oct 29, 2018)

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## volodar

> Cutaway is stupendous! 
> Must of been a huge bandsaw....Not being ex-Calvary or armor, I can only reason out a portion of components. Anyone aware of a labeled view?



My approach would be what I see Tuomas do all the time - but for this situation, a BIG angle grinder with suitable cutoff wheel.

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PJs (Oct 29, 2018),

Toolmaker51 (Oct 27, 2018)

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## Jon

Ship saw? Really though, I don't think they cut it in half uniformly like you might cut a sandwich in half. Probably a lot of planning so that they get the best museum-quality cutaway display. Not sure though! Maybe they used one of these:

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PJs (Oct 29, 2018),

ranald (Nov 3, 2018),

Seedtick (Nov 3, 2018),

Toolmaker51 (Oct 27, 2018)

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## Toolmaker51

> Ship saw? Really though, I don't think they cut it in half uniformly like you might cut a sandwich in half. Probably a lot of planning so that they get the best museum-quality cutaway display. Not sure though! Maybe they used one of these:



I like bandsaws plenty, but over-the-top is just crazy. This I'm certain is a wood cutting blade judging by tooth form, and 3 pitch. 3 _per foot_, not 3 per inch! Most astounding is the width. Used to be a comparably large saw on display, in lumber yard parking lot; 1980's Huntington Beach, CA., on Bolsa Chica south of 405 Fwy. That blade was about 3" wide, maybe 1/8" thick. I notice back side has abbreviated teeth too. Maybe this is for re-sawing of timber, back teeth to reduce binding, possibly more kerf as well.
And what's going on with one in upper left of picture? Pretty inconvenient storage?

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PJs (Oct 29, 2018)

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## Jon

Centurion cut in half. 1:28 video:

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PJs (Oct 29, 2018),

Seedtick (Nov 3, 2018)

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## Frank S

These cutaway displays are not cut in half as one might think. First whatever the model to be cut open happens to be the first step is a complete disassembly 
then they are cut by which ever happens to be the favored method. For the unusually thick Steel this is often done much like the breakers at scrap yards do by using a huge cutting torch some things are cut with demolition saws like my Sthil AS510 Av mine has a 12" blade guard but up to a 16" can be used 



other methods could include the diamond cable saw like those sometimes used to cleave granite slabs
or a band saw on anything that could be fit through one.
Once the sections are cut apart the model is cleaned and painted then re assembled sometimes even the smaller assemblies are cut open as well 
A guy told me one time that it can very easily cost double or triple to make a cutaway model as it did to manufacture it as a whole machine.
Some manufactures will actually cast or build a cut away model at the time of the machines original production run.

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Jon (Oct 29, 2018),

PJs (Nov 4, 2018),

Toolmaker51 (Nov 2, 2018),

volodar (Oct 30, 2018)

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## Jon

You're right, "cutaway" is more accurate than cut in half. Only something that is symmetric across the cut plane would best be cut "in half". Must take an extraordinary amount of planning. A tank is an excellent candidate for this type of display; visually interesting, complex, tightly-packed, and even enthusiasts may have never actually been inside of one.

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## Chips O'Tool

Using diamond tools on steel at high speed is not a great idea, because the diamond dissolves into the metal.

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## ranald

A cutaway of a Lamborghini was displayed at the Brisbane car show in early 70's. It showed, unintentionally, how the then European treatment of metal in cars was not up to our climate: surface rust everywhere. But it was still impressive all the same. That tank is impressive.

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## ranald

> I like bandsaws plenty, but over-the-top is just crazy. This I'm certain is a wood cutting blade judging by tooth form, and 3 pitch. 3 _per foot_, not 3 per inch! Most astounding is the width. Used to be a comparably large saw on display, in lumber yard parking lot; 1980's Huntington Beach, CA., on Bolsa Chica south of 405 Fwy. That blade was about 3" wide, maybe 1/8" thick. I notice back side has abbreviated teeth too. Maybe this is for re-sawing of timber, back teeth to reduce binding, possibly more kerf as well.
> And what's going on with one in upper left of picture? Pretty inconvenient storage?



It doesn't have the teeth on opposite side. Is the handler feeding the blade through to cut the back teeth? good gloves.

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## VinnieL

There was a bandsaw mill near my hometown in MO. I saw their saw sharpening shop. The blade looked a lot like this one, but no teeth on the back side, but it was probaly 3-4 times the length . The blades were mounted horizontally on rollers for sharpening we were cautioned they were scalpel sharp and they were. This mill sawed amlost anything cut locally but most all of it was sawn 3/4 inch thick for pallet construction, and most of it was pine.

My guess on the teeth on the back of the blade would be to clean out the sawdust and keep the kerf open.

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## Beserkleyboy

Guys. I found this site explaining the blade and timber mill operator in Oregon. 
https://www.core77.com/posts/52945/H...-Bandsaw-Blade

....now I wonder if you can fold that monster! Cheers
Jim

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12bolts (Nov 4, 2018),

Frank S (Nov 3, 2018),

Jon (Nov 5, 2018),

ranald (Nov 4, 2018),

Toolmaker51 (Nov 4, 2018)

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## ranald

I have enough trouble folding a saw blade for a 14". LOL Jim. Imagine the twang if it broke.

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## Beserkleyboy

Ranald, I'm with you! Took me years to learn...Our General Manager (and general mentor...) at the family timber yard was an old pro. He'd chuckle and tell me, 'I'm just gonna show ya ONE more time...' and then proceed to virtually throw the thing ( 196" blade on 32" Crescent) down on the ground and it would flop into 3 rings just like that.....

Jim

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## Toolmaker51

> Guys. I found this site explaining the blade and timber mill operator in Oregon. 
> https://www.core77.com/posts/52945/H...-Bandsaw-Blade
> 
> ....now I wonder if you can fold that monster! Cheers
> Jim



Salute for Berserkleyboy! aka Sherlock Holmes. Great sleuth-work on link to Hull-Oakes. Some unknown video here on HMT, drew up Hull-Oakes in the queue of suggested watching when the first completed. I never made the connection. 

As folding goes, I don't think a fifty-foot blade qualifies. They'd need a machine or eleventythree guys just to twist the figure 8; close to another team in a cheer squad pyramid to flip the arc down flat. And a pallet of good gloves, lol.

No recruits to unfold have come forward...really good off-shore marketing opportunity. I'd target any number of over populated under-employed areas. Or maybe a trade school pitch; "YOU can join the elite and highly paid world of bandsaw unfolders, no experience needed!" 

Then boneheaded employment recruiters would be hounding me again, just because 'bandsaw' appears in my resume. Just weeks back got a succession of contacts on mention of 'precision assembly of micro-mechanical and electronic components' which they mindlessly interpreted mere 'assembly' as equivalent. I put all four on the ropes, figuratively, demanding "who collected my authorization in truncating carefully detailed resume statements?". And "I'd not even cross a street for $13.00 an hour offered." "45+ industrial years for $2 bucks less than next proposed minimum wage?"
I'm sure, one pair of ears continue to ring.
_Morons!_
They must work on commission or volume of contacts made. Like the new auto dealer working [unsuccessfully] on my Dad, in a 2017 V8 Camaro. What a picture; barely 5'1'' and 98 years old with blocks tied on brake and gas pedals. Though I will say, it was a gorgeous emerald green.

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Beserkleyboy (Nov 4, 2018)

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## Beserkleyboy

Mate, it weren't that hard...actually! I just google image searched 'big bandsaw blades' and voila! But, hey, thanks for the kind thoughts.
Jim

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Toolmaker51 (Nov 4, 2018)

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## ranald

> Guys. I found this site explaining the blade and timber mill operator in Oregon. 
> https://www.core77.com/posts/52945/H...-Bandsaw-Blade
> 
> ....now I wonder if you can fold that monster! Cheers
> Jim



It would'nt download last time I looked, so, thanks Jim & hope my techno probs have gone! It looks like heaps of sparks from back angle, but from the front, it looks like just a "lick" & just as well due to replacement costs regardless of cost/benefit ratio. Funny though, size doesn't always relate directly to cost. I have a 14" carbatec generic saw where the finer/smaller (of same type of) blade is dearer per width than slightly wider ones: Quite different to my 14" laguna saw. Maybe the generic mid range ones are done in bulk according to demand: they are definately not as well packaged (who wants to receive a kinked blade in the mail).

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Beserkleyboy (Nov 4, 2018)

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## Beserkleyboy

Thanks , mate!

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## Hoosiersmoker

Looks like a similar blade here:
[/ATTACH]


And what? No safety glasses???
And this guy better be the owner or HE'S FIRED!
[ATTACH=CONFIG]26218

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Beserkleyboy (Nov 5, 2018)

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## suther51

> I like bandsaws plenty, but over-the-top is just crazy. This I'm certain is a wood cutting blade judging by tooth form, and 3 pitch. 3 _per foot_, not 3 per inch! Most astounding is the width. Used to be a comparably large saw on display, in lumber yard parking lot; 1980's Huntington Beach, CA., on Bolsa Chica south of 405 Fwy. That blade was about 3" wide, maybe 1/8" thick. I notice back side has abbreviated teeth too. Maybe this is for re-sawing of timber, back teeth to reduce binding, possibly more kerf as well.
> And what's going on with one in upper left of picture? Pretty inconvenient storage?



Some bandsaw mills have full teeth on both sides, carriage can cut traveling both ways, very efficient. These teeth look to be some thing else or they have hit some metal in the log and were damaged severely. 
Eric

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Beserkleyboy (Nov 5, 2018)

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## Jon

Your browser does not support the video tag.

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baja (Feb 5, 2019),

ranald (Feb 3, 2019),

Seedtick (Feb 4, 2019)

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## PJs

Must'a been hot water...Really Hot...No steam??

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## tonyfoale

> Must'a been hot water...Really Hot...No steam??



Looks suspicious.

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PJs (Feb 7, 2019)

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