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0t---death by tool shank

JHOLLAND1

Titanium
Joined
Oct 8, 2005
Location
western washington state
fall 1985

a call from hospital er interrupts my clinic day--
62 year old logger/saw mill operator with metal foreign object imbeded in
anterior skull base

he is coherent but leaves information stream to wife
operating his 40 hp electric powered portable sawmill when struck from component of 60 in circular blade

exam reveals modest entry wound just below left eye
vision preserved cardinal eye motions ok
x-ray shows half moon silver dollar size shank insert imbeded in skull base
passing thru left cheek-maxillary sinus around a millimeter from internal carotid artery entry
to brain
the shank followed a circular entry path into Lewie's cheek--and that is how i extracted it--
180 degree rotation no bleeding no drama--we irrigated site and he was on his way

a long and beneficial relationship ensued--Lewie purchased several detroit diesel engines from me
--followed by my acquisition of shop tools

my analysis of discrete aspects of this event---

60 inch saw was spinning 570 rpm giving 8500 surface feet/min thru doug fir
Lewie took me to mill for detailed review--circular blade was type 3 insert machined--the most
hazardous --imo

reason---no boss is present in blade geometry blocking full roll out of tooth-bit holding shank

the shank is a locking feature maintaining cutting tooth--aka bit--in position
both shanks and bits have ground v trough which locks on complimentary v prismatic land on saw body

newer designs have terminal boss which prevents full shank roll thru

german circular saws incorporate single element inserts with robust terminal boss

on that particular day in that unique circumstance--Lewie was the luckiest sawyer in the county



special note regarding linked video---the type 3 insert is featured--more to the point inserts in this blade present extreem hazard--
the pawl or finger holding tooth-bit have narrow base with rust -age-use embrittlement--a guaranteed mal-occurence
set-up


Pulling and Inserting New Saw Teeth - YouTube
 

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Last edited:
Interesting, lucky for sure.

Although not so common now, there were a lot of number pattern saws used over the years. This is the first I've heard of one throwing out of the plate.


Sent from my iPhone using Tapatalk
 








 
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