Pressure treated lumber/accident analysis

[C Edward Moore]

I went over to my friend's shop and we did our best to analyze what happened and what caused him to nearly cut his left thumb off on his tablesaw. My earlier comments about the board pinching is way off the mark. By making several rips he was cutting a groove about 3/8 or 1/2 inch wide. This cut was the last of the sequence, so there is no way that pinching could have occurred. An examination of the boards showed no blade marks indicating that the board had been hurled off the saw -- the cuts were all clean.

He has a square V-mark in his chest as if the end of a board had struck him. On the off-chance that he had touched the back of the blade with the push-stick in his left hand, I asked to see that stick. It was regarded as scrap and had inadvertently been tossed on the burn pile. We simply don't know if it had any blade marks on it. From his description of it, it probably could not have caused the mark on his chest.

His first memory after the incident is of standing to the left of the saw with his left hand and thumb on the table. I wondered if he might have slipped on sawdust or even blacked out for a moment, hitting his chest on the end of the fence rail. The cut across the thumb joint suggests that the hand traveled across the blade from the front of the saw and not the side.

This is a bright and safety-conscious man who has made lots of furniture over the years. I don't think we will ever know exactly what happened to cause his left hand to go into the blade, cutting him across the joint at the base of his thumb, on the palm side.

 

[dkulze]

by "front of the blade" do you mean the side towards him as he stands at the saw?

Did you try leaning against the saw in a manner that would replicate the injury to the chest and then stretching hand out on the table to see if it intersects properly? Actually, hand on the blade as it would have been cut then moving around the saw until you get the mark might work. Did that already? (probably but just checking)

Sounds like the slip hypothesis might be the most likely.

Can exposure to Copper Arsenic dust cause dizzyness?

Dietrich

 

[C Edward Moore]

Dietrich,

Thanks for your thoughts. I thought about the slipping after we left, so I will see him tomorrow in church and suggest your approach.

By "front of the blade" I mean the view from the front of the saw.

I cleaned his saw and blade today and warned him about the chemical hazards of treated wood.

With the saw turned off, I had him feed the board through and show me his hand motions. This board is a 2x4 ripped in half and the groove is being cut in the fresh surface. Basically it is about 1 1/2" square in cross-section. Nothing that he did looked wrong, nor looked as if it could have led to a problem. I gave him 3 new push sticks that are a little beefier than his plastic ones.

Thanks,

 

[Jeff Jilg]

It's difficult to get a full picture of what could have happened. But maybe he did slip or was brushing something out of the way. Maybe a bug flew across his vision and he was brushing that away. Then by mistake he got off balance and got his hand near the blade.

One time I was using one of those hedge trimmers with the 100 teeth that go back and forth. There was a lizard on the bush and I went to brush him away. Long story short is that I only got a minor cut (2 stitches). I might not have remembered it, but after the incident Theresa asked me how it happened. So it's good to go back and analyze it. Now when I do the hedge trimmer and I get distracted I take my hand away from the trigger and turn it off.

 

[theeviltwinn]

I have heard of people having memory problems caused by working with pt wood. Does he use it a lot? Does he where a resperator?

Mike