On Site Mortising Tools?

[Woodbender]

I'm trying to be a pest today.

I've seen the hand crank Boring Tool on E-bay etc.  But.  What other options are being (successfully) used in the field for mortising timbers.  Is there a mortising bit which can be fit into a perpendicular jig on site and mortise a post or a beam on a couple saw horses? Should I think in terms of multiple passes with an auger and a corner chisel from Lee Valley or Japan Woodworker?

What are people using? I'm not necessarily a purist, I just want an accurate joint when I'm done.

Thanks again.

[Raphael]

I use traditional hand crank boring machines and wouldn't trade for anything less than a Mafel chain mortiser.

  A ship auger in a low speed high torque power drill is about the best modern alternative without spending big money on a purpose built chain mortiser.  Depending on what you have at hand and how you jig it, this could cost a lot more than buying a traditional boring machine.  The (well made) drilling jigs I've seen are selling for more than I paid for my Miller Falls.

Corner chisels can be really handy but aren't necessary, a good 1½" framing chisel is a must.

[scgargoyle]

Makita makes a chain mortiser that goes for about $1400. Too rich for my blood, but it's probably pretty fast and accurate. Like anything else, it probably takes some skill to use.

[logman]

Get a chain mortiser.  They would have used one 200 years ago if they had it. 

[Jayson]

Working with a couple of guys that just finished a frame with t-augers. They were on a payroll and said "it was fun". So it is possible. Old boring machines are fun too. Those tools are also harder to make very serious and quickly executed mistakes. You need more time using these tools. Unless of coarse you can find a seasoned boring machine operator like Raphael to contract your mortices to. I would imagine he could feasibly keep up with a man and a mortiser especially if power is not readily available. Has anyone ever tested this theory? If not is anyone in a position to? I would love to know. I bought a mortiser(it was around $1400) but I was fortunate enough to be working with someone that helped on the initial acquisition of it(loaned me the money). As far as ship augers and drills go I would look for double spurred bits because they seem to be less prone to tear out (ripping out wood beyond the hole) on entry, than most store bought auger bits (single spur). Another trick to avoid that tear out is to start your holes with a forstner bit and then stick the auger in. Look out for the tear out on exit of most methods if it is a thru hole or mortise. I avoid that by having a spotter or marking my bit so the tip just pokes out and then turn the timber over and finish from the other side. I would also suggest trying to buddy up with someone close by that perhaps you could do some tool sharing with. I have also found that timber framing tools hold their value pretty well if they are not abused. So you could buy one and sell it when you are through.Good luck. Hey Raphael if you want to time some boring let me know and I will take a stopwatch to the shop this week. Just start your watch when you open the tool shed door and let me know what size holes or mortises you want to do. You can probably hire a guy that has one(mortise) to come rough out all your mortises.JMO

[Raphael]

  I might put on a pretty show vs. a chain mortiser if overboring was not allowed.  I think beating a Makita is doable in some circumstances but I don't have any direct experiance with them.

Jack Sobon thought he could beat the Mafel.
I'd like to see that. ;D

[Stumpkin]

I have four boring machines gathering dust. I would love to use them, they all work fine with a sharp bit. I don't like to use them on hardwoods, especially dry hardwoods. I have seen old castings and gears broken and twisted. I can still buy parts for my Makita chain morticer but not for the Millers Falls or The Boss Double Eagle.

As an itinerant timber framer here in the mid-west I work mostly with recycled hardwoods. The only project I have done in the last three years that used green softwoods was in Georga last August. I was glad for the breeze from the motor on the chain morticer.

I talked with an "old timer" once at a demonstration I was giving. He had been watching off to the side as I showed some children how the boring machine was used. After the kids got board an ran off, he told me that as a boy he had worked on a barn framing crew. Because he was the youngest on the crew, he had to drill all the mortices. Man, was he smiling when I showed him my chain morticer.

With any tool there is a learning curve, someone who has a lot of hours on a chain morticer would be hard to beat with a boring machine. The Mafell is faster than the Makita, but only in the right hands. I am convinced that morticing is a sequential process. If you consistantly do things in the right order you will become more efficient, regardless of what tool you are using. The biggest advantage to using a chain moritcer is the number of mortices you can do in a day not how much faster you can do one mortice.
Tom

[Raphael]

  Indeed, if I were equipping a production shop I'd certainly not be buying old hand crank boring machines to do so, especially at some of the prices I've seen people pay for them.  On the other hand I have a very hard time recomending that someone pay ten times the cost of a good boring machine for a chain morticer they only plan on using for a single frame.

  One Makita = 40hrs. of itinerate labor, so if you're going to pay $1400 to get your mortices bored quickly, lay them all out and hire Tom to do it.  He might just teach you a thing or two in the process.  On the other hand if you're willing to buy a Mafell to cut a single frame I'll be more than happy to take it off your hands at half price when you're done with it.  :D

  One thing you can do with a boring machine you can't do with a chain morticer connected to a roaring 5.5kw generator is pause to watch the deer wander through your building site.  That's something that has value (to me) that can't be measured in time or money.

[Woodbender]

  (snip)
One thing you can do with a boring machine you can't do with a chain morticer connected to a roaring 5.5kw generator is pause to watch the deer wander through your building site.  That's something that has value (to me) that can't be measured in time or money.

Thanks guys - all good comments.

Is this a great place to hang out or what?

[Jim_Rogers]

To prevent tear out from any bit or chain mortiser a mortise should be knifed all the way around the perimeter. We do this with all mortises and press the knife in three times, once lightly to score the surface fibers and create a good straight line, second time deeper and third time deep as possible.
This knifing or scoring of the perimeter will prevent the tear out from happening.

Through mortises are bored from both sides so, knife scoring on the second side is standard procedure.

Peg hole boring requires similar scoring but you do it with the bit itself. As you layout your hole location you prick the location with a carpenters awl creating a depression for the bit's tip lead screw. Place your bit, whether it's in a brace, electric drill or boring machine into this depression and turn the bit backwards or counter-clockwise until the wings of the bit score the circle of the hole. Then turn forward or clockwise to start boring your peg hole.
Once the tip of the lead screw breaks the surface on the bottom of the timber, as mentioned above, roll the timber over and again turn the bit backwards to start, until the wings score the circle for the peg hole, then again, turn forward and finish your hole.
This will prevent peg hole blow/chip out....

Jim Rogers

[Jayson]

Hey just wanted to mention that I saw tri fluted drill bits by Irvin at Lowe's. They maybe worth checking out. I would imagine they nice clean cutters.Hey Tom