Marples Chisel Fracture
Welcome! / Forums / General Woodworking Discussions / Tools and Tool Maintenance/Restoration / Marples Chisel Fracture
- This topic has 4 replies, 4 voices, and was last updated 8 years, 11 months ago by markh.
-
AuthorPosts
-
This is a new one on me….. I was chopping a through mortise in oak with this 3/4″ Marples chisel and my Thorex 712. As I was levering out the waste, the corner of the chisel broke off. I’m not sure how old this chisel is, but it has served me well in the past; the back is quite flat and it holds (held?) an edge well. I was just wondering if anyone else has had a similar occurrence? In the meantime, it’s back to my old Stanley 750.
[attachment file=”DSCN0295.JPG”]
[attachment file=”DSCN0296.JPG”]
[attachment file=”DSCN0298.JPG”]
Attachments:
You must be logged in to view attached files.22 April 2015 at 9:41 am #126642Your real name isn’t Bruce Banner is it?
It does happen. I snapped 3/4″ off the end of a 1/4″ Marples blue chip on my first ever project. I know I was going at it too hard now, but at the time I was very inexperienced, using far too much force on blunt tools (having only just realised that chisels could be sharpened at all…). Not a difficult fix for the chisel, but getting the bit lodged in the mortise prised out was a pain in the arse.
Then there was the inch I took off the end of a second-hand 1″ firmer trying to hammer it flat. The sharp end whizzed over my shoulder and I still haven’t found it. Another lesson learned.
I’m better now though, honest.
It’s funny, you’d think the Marples with their soft steel would be less likely to fracture, but here we are with a pair between us. Were you using a lot of force on yours or was it a complete surprise?
Matt.
Complete surprise….. I had just sharpened up and was chopping the mortise just the same as I have done many times in the past. There definitely wasn’t too much force used. I’ve been using that same set for well over a year now; shortly after I started WWMC. The only thing I can think of is perhaps I sharpened (over time) to a spot where there was an internal flaw in the steel…. When I sharpened this time, it wasn’t even dull or in bad shape. I only used my fine and super-fine eze-lap plates, followed as usual by the leather strop with chromium oxide. Nothing out of the ordinary at all.
22 April 2015 at 9:22 pm #126658Well, that’s a bummer Gary. If you don’t have an electric grinder (like me), that’ll take a while to grind the chip away. How will you deal with it?
Hi Gary,
With all of these mass produced chisels in the 50’s and 60’s there would have been variations in the final “as tempered” hardness achieved by the manufacturers. Yours may have been at the upper end of the hardness spectrum! You may find that during the grinding process to restore the edge that a little of the hardness comes off the steel – effectively self tempering it – particularly if you let it get a little warmer during this process. But, as you say, there may well have been a small internal defect in the steel used – not uncommon in all steels. This may be visible on the fracture surface as a slight darkening of the surface if you look at it with an eye loupe (magnifier). If the fracture is mostly crystalline – then its more likely to have been just brittle (too hard). Another manifestation of the trade off between hardness and toughness!
Cheers, Mark Heady -
AuthorPosts
- You must be logged in to reply to this topic.