Thread: 30 second mortise -with hand tools challenge

Your in the "Hand tools Unpowered" section so you do mean no power?
The mortise chisel and Mallet or Maul has to be the fastest way with hand tools but its not a 30 second job.

30 seconds is electric powered chisel mortiser territory . Or chain and chisel. Or more modern set ups .

Best reveal now. I have never even considered a 30 sec mortice. Be going some to even mark it out in that time so no ideas from me.
Regards
John

With hand tools - not electrons. 30 seconds does sound OTT.

I could not make a mortise 12x25 in 30 seconds with a mortise chisel by hand, even if powered in with a sledge hammer. More like 6 or 7 minutes to make that depth, in hardwood.

Any other suggestions? Ideas?

Hint - there is medieval tool that is nearly as fast as what I do. I found it as I assumed someone had figured this out before. I have no idea why that tool has essentially disappeared.

This what you mean.
Twybil - Wikipedia
Regards
John

So it is not too unrealistic - mark out time is seperate. I guess that could be fast with a mark out jig but that another "thing".

Too big a hint - that was fast for an uncommon tool

I will take a photo of the the tools I use tomorrow for one of the methods. There's still a second to explain. I didn't exactly recreate a twybil.

Ok, I'll play, bore out with brace and appropriate bit, then pare the corners to square . . .

What is a Twybil?

Hi Pat,

A Tywbil is a fast mortise making tool, John put a wikipedia link up in his reply, above.

Will put some photos up later of one of the ways, I use to make mortises quickly.

Here is my motley crew for fast mortising- a star M F type, a ham knife, (cheese chisel) and a bolt

mortise tools.jpg

One method for a 30 second mortise

Step 1


The star M fits tight in a Stanley 78 brace. It pretty fast and cuts quickly into hardwoods - this used to produce two holes at either end of the mortise.
Excluding marking the drill points maybe 10 seconds to drill two holes.


Step 2 the ham knife


Preamble
Chisels has a limitations as they are a single bevel tool, no matter how hard you hammer it will stop cutting. The bevel pushes the chisel into the opposite cut wall. This develops friction and quickly the resistance to further penetration is high. The tool when pushed hard starts crushing timber and loses effective.

A Ham knife on the other hand is a double bevel tool and relatively thin. The friction is better balanced on both side and substantially lower - allowing deeper penetration. Guidance can be an issue as the thin body can deflect.

Method- Cut transversely.

Align the edge of the ham knife with the width of the mortise. The ends of the ham knife should be aligned with perimter of the two holes drilled. Hammer down to required depth. Withdraw the ham knife and repeat on the other side.

12 seconds or so

Step 3- the bolt

We bow have a narrow pillar or wood with a relatively weak base. Drop the bolt into the hole furtherest from the edge and push over the pillar. Assuming all the prior cuts where accurate this should break at the base

8 seconds

All going well - you now have a round ended mortise.

Notes on this method.

1- Prefer square mortises and a will align the ham knife with the ends meet the mortise. The makes it easier to clean up the ends.
2- If refinement is required, a bevel down chisel cleans up the base quickly
3- I have made Ham knifes (cheese chisels) from $3 craftwright scraper. In a short length these can take the hammering
4 - there are "leather knifes" available from the usual suspects on the internet that look similar to my ham knife.

Why, unless you greatly suffer from an attention deficit, do you need to worry about the time it takes to chop a mortice. It's like the sharpening fanatics that say: I can shave 10 seconds off if I buy a $200 diamond wheel for grinding chisels... You're a hobbiest... Unless you're in your eighties, time isn't an issue. It's about enjoying the process and the end result.

Interesting tool; but probably best suited only for green timber as per the Wiki page and THIS VIDEO