Sciencemadness Discussion Board

High speed chips from chiseling

wg48temp9 - 21-6-2021 at 10:20

The usual advice for the care of cold chisels is to grind off the mushroomed head to avoid the dangers of flying metal chips. I have never had a problem of flying metal chips or I hadn't until yesterday.

I was using a cold chisel to attempt to prise off a sleeve from a shaft On one swift hit of the chisel with a hammer I felt an intense pain in one of my fingers which began to bleed. Apparently a flying small chip of metal had punctured the end of my middle finger. The chisel was new and not mushroomed. On consideration of the position of the puncture in relation to the chisel, the chip was probably piece of the hardened (assumed) steel sleeve.

Unfortunately today the area round the puncture is red and tender. I had assumed the chip was large compared to puncture. I checked with a strong magnets, I can feel an attraction so the metal chip is under the skin The metal chip must be small but was moving so fast it is now a millimeter or more below skin surface.

When I have dug the metal chip out I will take a picture of it and post it. When the wound was fresh I may have been able to pull the chip with the strong magnet. No MRIs for me.

Of course the morel of the story is wear hand and eye protection for such operations.

PS: I manged to get the chip out. Its about 2 x 3 mm across and much less than millimeter in thickness. Probably a few mg in mass. I am very surprised it had sufficient velocity to penetrate the relatively tough
skin of my finger tip.

[Edited on 6/21/2021 by wg48temp9]

zwt2 - 21-6-2021 at 11:09

the morel of the story

Morel_Mushroom-1 - Copy.jpg - 120kB

unionised - 21-6-2021 at 11:37

I'm not sure of the date, but the tree we were dropping was an elm- it had Dutch elm disease. That suggests about 1975 and that's close enough.
I wasn't really doing much- I was a schoolkid. But I was "helping out" in the way kids do.
The tree was down and we (well, the adults) were breaking up the tree so they could burn it.
And they were using wedges and a sledge hammer.

The bit that came off the mushroomed head of the wedge hit my right thumb- just where the nail bed ends.

I was young, so the wound healed quickly enough, but the nail on that thumb is still distorted.

So, yes, it's an important issue which is easy to overlook.
If the heads on the wedges are getting mushroomed, grind them back to shape.

unionised - 21-6-2021 at 11:41

Quote: Originally posted by zwt2  
the morel of the story

I see you are the Fun Guy around here.

wg48temp9 - 23-6-2021 at 14:51

Below is a pic of the steel chip on the mm scale of a ruler. There is a magnet holding the ruler and the chip.

steel-chip-ad.jpg - 72kB

violet sin - 23-6-2021 at 22:15

High speed (tool) steel... Well a razor blade. Carefully drug across finger at a low/med speed (to be read as, accidentally gored myself) in an attempt to cut out a drywall crack prior to mudding. Was on an outside angle of the wall next to a light switch. It's not deep, I'm fairly thick skinned. But I immediately felt super bright about then.

IMG_20210623_224239105.jpg - 2.1MB

Painters tape and triple antibiotic ointment = win.

IMG_20210623_230745.jpg - 1.2MB

Note the offending knife, broken face paper section of drywall and blood offering on floor. The moral of the story here, drink more coffee doing afterhours side work. Or just don't try to catch metal with skin meats. Or, keep first aid essentials on hand... There are a few lessons.