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Sawmill head came off the rails while running.

Started by Joe Hillmann, July 16, 2014, 12:33:51 PM

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Joe Hillmann

I had a bit of an accident with my homemade mill last night and figured I would post it here to maybe prevent someone else with a homemade mill from having the same problem.

I was sawing through a log with the head raised about 15 inches.  A foot or so into the log the entire head and carriage started to tip backwards toward me rather slowly.  Luckily I ran away from the mill rather than trying to prevent it from falling.   After a few seconds the blade came off the wheels and the head slammed into the rails it broke off every fin from the flywheel and sent them out like bullets.  It took about 30 seconds for the pieces to stop flying before I felt it was safe enough to go near the mill to shut it off.

It took a while to figure out what had happened.  It looks as though the cable I use to raise and lower the head had came unhooked from part of the carriage causing the head to want to fall but since the blade was in the wood it couldn't fall down it had to fall backwards.

There are two things I could have done to prevent it.  Making better connections between the cable and the carriage and having some type of hook on the carriage that goes under the rails so it couldn't have come off even it did start to tip.


So far it looks like the only real damage to the mill was the blade, one wheel that the blade bit into, the flywheel (hopefully the crankshaft isn't bent) the gas tank, quite a bit of the wiring, one blade guide, the cable, the water/solvent system and the engine shroud.  It could have been a lot worse, like I said I am posting this to maybe prevent it from happening to someone else.

HI Rancher

Quote from: Joe Hillmann on July 16, 2014, 12:33:51 PM

So far it looks like the only real damage to the mill was the blade, one wheel that the blade bit into, the flywheel (hopefully the crankshaft isn't bent) the gas tank, quite a bit of the wiring, one blade guide, the cable, the water/solvent system and the engine shroud.  It could have been a lot worse, like I said I am posting this to maybe prevent it from happening to someone else.


Yikes!  Would the list of stuff not messed-up have been shorter :o?  At least you had the presence of mind to get recognize what was going on and get the heck away from the mayhem. 

Best of luck pulling it all back together and gittn back in the saddle.

Mike

Magicman

Also a flange or whatever riding beneath the rails to prevent the head from lifting off of the rails.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Joe Hillmann

Quote from: Magicman on July 16, 2014, 01:08:31 PM
Also a flange or whatever riding beneath the rails to prevent the head from lifting off of the rails.

That is what I meant when I said some type of hook under the rail,  I just didn't describe it as well as you did. 

Magicman

OK, and I missed your "hook" statement.   ;D
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

StimW

New HF Band Mill
Branson 35 hp 4 WD Diesel Tractor W/Attachments- Backhoe, FEL W/ Bucket or Forks, 4' Tiller
4000# Clark Forklift W/24" Tires
Promark 6" Brush chipper W/18 hp Kohler

thecfarm

That is too bad, But thanks for the warning. The Thomas that I have just has a piece of flat stock under the rail,just for that reason.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Joe Hillmann

Quote from: StimW on July 16, 2014, 03:02:03 PM
What kind of engine is it?

A kohler 321.  I found a flywheel for it on craigslist for about $55 including shipping and I figure I should be able to beat the dents out of the cowling.  If more than that is damaged, I have a 20 hp Briggs that I could use but would require changing the engine mounts so I don't want to do that unless I have to.

scully

Your post is very valuable ! There is much to be learned here with what happened ,home made mill bulders will bennifit from your experiance . Good move getting back ! I can imagine it was sorta like a helicopter crash and they suck
I bleed orange  .

ladylake


I'd move the rear track rollers back farther so it wouldn't want to tip back. A hook under the rail is fine for safety but not for sawing unless it was real tight as you wouldn't want the head tilting back even a little bit when sawing.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

schmism

Quote from: Joe Hillmann on July 16, 2014, 12:33:51 PM
There are two things I could have done to prevent it.  Making better connections between the cable and the carriage and having some type of hook on the carriage that goes under the rails so it couldn't have come off even it did start to tip.

Ditch the failure prone cable arrangement and go with a lead screw setup.   Sure its more expensive but medical bills from accidents like the above are certainly much more expensive.

http://www.mscdirect.com/product/details/01206184
039 Stihl 010AV  NH TC33D FEL, with toys

36 coupe

Thats the problem will home  made work.Little concern with safety,Most home built mills have no blade covers.My Thomas mill has hooks to keep it on the tracks.Plus stops on both ends of the track.

ladylake

Quote from: schmism on July 16, 2014, 05:38:52 PM
Quote from: Joe Hillmann on July 16, 2014, 12:33:51 PM
There are two things I could have done to prevent it.  Making better connections between the cable and the carriage and having some type of hook on the carriage that goes under the rails so it couldn't have come off even it did start to tip.

Ditch the failure prone cable arrangement and go with a lead screw setup.   Sure its more expensive but medical bills from accidents like the above are certainly much more expensive.

http://www.mscdirect.com/product/details/01206184



If you use acme treads on any mill use bronze nuts, the really hard nuts on my TK lasted real good with the lighter Kohler gas engine it came with but the acme rods wore out way to fast after I put the way heavier diesel on the mill maybe 500 hours with the diesel.  After switching to bronze nuts I haven't had to replace either the rods or nuts in over 2500 hour and the rods still look like new, I don't know about the nuts as I can't see them. One advantage of acme threads is once stopped they stay put.   As I mentioned above get those rear rollers far enough back so the head won't tip back when sawing hard.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Nomad

     Good advice given.  And glad to hear you got out of harm's way!
Buying a hammer doesn't make you a carpenter
WoodMizer LT50HDD51-WR
Lucas DSM23-19

drobertson

only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

bandmiller2

This underlines the importance of a kill switch and an unobstructed escape route. Frank C.
A man armed with common sense is packing a big piece

Joe Hillmann

Quote from: bandmiller2 on July 16, 2014, 08:18:56 PM
This underlines the importance of a kill switch and an unobstructed escape route. Frank C.

In this case a kill switch wouldn't have done any good unless it was something like a boat has where one end gets clipped to the driver and the other end to the switch.  When it started to tip my first reaction was to get away not turn off the key.

YellowHammer

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Southside

Quote from: scully on July 16, 2014, 05:18:52 PM
! I can imagine it was sorta like a helicopter crash and they suck

Scully,

My father in law totaled a really nice Bell when he laid it down on a glacier in Alaska during a white out, was actually some pretty impressive flying as 5 other birds went down in the same spot and nobody walked away from those.   The subsequent paperwork sucked more than the crash. 
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

36 coupe

Quote from: thecfarm on July 16, 2014, 03:56:14 PM
That is too bad, But thanks for the warning. The Thomas that I have just has a piece of flat stock under the rail,just for that reason.
The Thomas mill will drop to idle speed if the throttle is released and stop the blade.Good safety feature.If a cable did let go you would let go of the throttle fast.A toggle type kill switch can be added to any mill.

5quarter

It's tough to think of everything when you're the Engineer, the Manufacturer, The maintenance guy and the test pilot.  ;)  Some re-engineering and you should be up and running better (and safer) than ever.
What is this leisure time of which you speak?
Blue Harbor Refinishing

Swatson

Wow...I am glad I found this thread.  I had been thinking of a way to put anti tip on my carriage.  I left the C channel I used for my frame with the hollow facing out for putting rollers in there but it was going to be a little complex having to find some good rollers and make adjustments.  The flat plate with a little clearance will work perfectly and is super simple.  My unit is stationary so travel stability is not a concern but preventing tip over is.
I cant figure out which one I like better: working with wood or making the tools to work with wood.

FarmingSawyer

Quote from: thecfarm on July 16, 2014, 03:56:14 PM
The Thomas that I have just has a piece of flat stock under the rail,just for that reason.

The "L" of the flat stock is too short for my tastes... I've pulled the mill off it's tracks walking backwards one day and I clipped a dog which was sticking out into the mill's path. It jarred the head so badly it hopped off the track and fell catywompus 1/2 into the mill and 1/2 off. It took my tractor, 3 of us, 2 hours and a lot of swearing to get the husk back on the rails without damaging anything. I now always take the dogs that aren't in use for a given days cutting and put them aside. I rarely use more than two, and if I need to swap them around or add a third it's really easy.
Thomas 8020, Stihl 039, Stihl 036, Homelite Super EZ, Case 385, Team of Drafts

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