Timber Framing Tools - Specifically Tenon Cutter

[Stuart Caruk]

I've been milling beams for timber framers for a while, and after watching several different craftsmen, and a couple butchers, I decided to give it a go. I quickly learned that for bigger beams I really prefer the Timberlinx connectors, but they seemed like overkill for smaller beams. I built up a jig to use a router to cut the housed joints in posts, but figured there had to be a better way. Lo and behold, I just found a Makita Timber Frame Router. It will fit on a beam about 12 1/2" wide and cuts to about 2 1/2' DEEP. It's set up to cut with straight, and dovetailed bits. It looks like this...



I also found several different Tenon cutters. I've never seen such a tool before. There are 3 different versions, made by Makita, Ryobi, and Hitachi. All of them use the same style with 4 blades. There's a video of one in action here https://www.youtube.com/watch?v=ANCmMOuB-Vw (sorry, I have no idea how to upload a video file to this site)

So which one would be the most reliable of the brands noted. Surely someone on this forum has one of these.







My original plan was to use a Fanuc 430iCF Industrial Robot with a 24,000 RPM router to cut the joints, but that seemed overkill for such simple joints. I'd rather take the tool to the beam, than move the beam to the robot.

[Ljohnsaw]

Wow, that is pretty amazing.  Almost seems like cheating! :D

[Stuart Caruk]

I learned a long time ago that time is money. That's why most all of my machines are fully automated. Sawmills are a bit different. Moving big beams around without a huge warehouse and a crane is a royal PITA. But I already have the equipment to handle them if I can bring tools to the beams. I'm all for cheating if it can make a better product faster. Surprisingly, the tools are very affordable. Not to mention tax deductible...

[Ianab]

While I have the utmost respect for the guys that can make those joints by hand, that's fine if you are doing it for the love, or are being paid by the hour.

If you are paid by the beam / joint, then you want a machine to help you.  :D

That tenon cutter would sure speeds things up, and if you have a trolley for moving the timbers around, or lay the beams out on a deck, set to the same height as the clamp you would be able to motor through the cuts.

[Don P]

The timberframers have just left the current barn job but they were using that first Makita router jig. We had tool envy, he thought it was out of production. It worked well, I could see it in the right setting. Having just had shoulder surgery #2, my pounder is done, machines good.

[Roger Nair]

All of these items are gray market, current in Japan but without manufacturers support in the USA.  Supposedly there was a problem with Underwriters Lab approval, rather than producing an north American version, they were removed from the market around year 2000.

[Dave Shepard]

There is always a trade off. If you have to start surfacing your timbers, changing your design, and maintaining expensive tools, then you have to figure that into your overall operating cost. I worked in a shop that had a new, expensive chain mortiser. It worked ok for a while. Then it got dull. As there was no spare chain, and scheduling was already out of control, there were a lot of mortises cut with the smoke and burn method. To set up with 1.5" and 2"  bars and spare chains is a lot of money, plus sharpening and shipping fees. On top of all this, these tools often don't cut the joinery the way it's supposed to be cut. I see them as a way to have an unskilled employed poking holes in expensive timbers,  and hope that they get it right often enough to offset the cost of their mistskes.

[rjwoelk]

I guess if the chainmortiser was maintained like the rest of the equipment it would help. We dont work with dull chisels. Why work with a dull chain.

[Dave Shepard]

 It was a poorly managed shop. My point was that in order for these tools to be effective, they can require costly maintenance.

[Stuart Caruk]

I've been running my own CNC shop for years. One thing that always cracks me up, and I enjoy greatly is competing with shops that do things today the way their parents did 20 or 30 years ago. Some still have machines and manual operators, some have upgraded to CNC, but try to stick with manual feeds and speeds. When I watch shops poking in a 7/8" holes through a chunk of 4140 4" thick and spending 3 1/2 minutes a hole I just shake my head. I do the same hole in 4 seconds using a Kentip high speed coolant fed carbide drill. When you're poking 600 holes in a part, the times savings is huge.

A chain morticer to me is no different. The chain is disposable or sharpenable. I don't own a single tool used in my CNC machines that doesn't have several spare inserts. Even lowly drills have several backups, and I even have a $5000 automated drill bit sharpener for the jobs that take a fresh tip on every hole.

You have to factor in the cost of maintenance and spare parts, but I found a simple formula years ago. If you want to make a little money, you spend a little money on your tools. If you want to make more, you spend more money on your tools. I personally like to create things. I just have little patience for tedium. And besides, I like to collect unique tools. Someday someone else will get them from my estate sale.

[Roger Nair]

I, now retired, had a Mafell chain mortiser.  Every day after shutdown, I removed the bar and cleaned and regreased.  The chain went into an oil bath, the second chain came out of the oil bath and hung up to drip into the bath.  When the edge wore, I hand filed the chain locked into a jig that held the chain tight and regulated the slope on the file.  Never did I have a smoking cut or a frozen link.  I was a very liberal user of high temp grease and oil.  Anytime the chain was refusing to bite and throw chips, we changed out and sharpened.  It is so simple.  In about 10 minutes a chain can be sharpened if you don't grind the bugger to uselessness.

[Dave Shepard]

We were using carbide chain and cans of lube. We still had a rapid rate of wear and no way to sharpen the chain. I don't work there anymore.

Be cautious of making too many parallels between mn machining and timber framing. You compare cnc drilling to manual drilling. Both are drilling operations with the samee net result. Mortises, abd other mechanized timber framing tools, are not necessarily creating the same product.

A mortiser may cut a mortise a little faster than doing it by hand, but mortising is only a small fraction of the overall workload.  So you may be saving ten percent labor time on the mortise, but only two percent on the whole project.

You may find that the investment pays off for you, but it will take a lot of work to pay for any large investment.