A Look at Hitachi Beam Mortisers

My shop has two new additions, a hitachi  chain mortiser and hollow chisel beam mortiser.  These tools are for cutting timber framing mortises in beam sections typical of Japanese wooden architecture. When I first got hard into carpentry they seemed like rare unicorns, not available in the American market. Last time I looked, there’s sellers on ebay offering every major brand now, Hitachi, Makita, Ryobi. And these tools are even more common on Yahoo Japan auctions, just with better prices and more selection.  I had intended to only get the hollow chisel mortiser, but at only 6,000 yen the chain mortiser was too good a deal to pass up on, plus I like the color, haha.  Take two zeros off to get the rough yen to dollar conversion.

The only shipping option other than Sea Mail was EMS, both of which I assume use USPS to get the box to your door, so this was a major test of shipping and handling reliability. I paid extra for protective packaging, which apparently meant entombing the parcels in heavy bubble wrap. I would have appreciated double boxing at a minimum short of crating, but through some miracle they arrived nearly undamaged, mainly due to the robust quality of the castings and parts on these machines.

Hitachi’s CB21 chain mortiser, as it arrived. It’s used, so of course a bit of rust and a broken plastic adjustment knob from shipping damage. The chain mortisers seem to sell for quite a bit less than the hollow chisel mortisers in general. I could be wrong about this, but it looked like this model is out of production, and I couldn’t find replacement chains from any Japanese merchants which could be part of the low price I paid. I’m holding out hope though that I can find a chain from a different manufacturer that will fit.  

I got her all cleaned up and lubricated, ready to test. The chain was still nice and sharp. Both of these machines are meant to run at 100v, and I read through lots and lots of debate about whether or not its advisable to run them at 120 volts without a voltage converter. In general it doesn’t seem to be a problem, but maybe will shorten the motor life a bit.  One of the major limitations of this machine is the maximum width of beam it can ride. At full open between the clamps you get about 7.5″, rather inconvenient if you think you’re going to be mortising a bunch of 8×8’s.  The chain is 18mm wide, so can cut your typical 30mm wide mortise with a single throw of the axis control. I love though how robust the guide rods and casting are on this thing compared to the Makita 7104. Once I got it cleaned up and lubed its really smooth and rigid.

This is a shot of the lever arm that controls side to side movement of the chain. It has presets for different widths of mortises.

Here’s the other side of that control lever. For some reason as the numbers here get bigger the mortises get narrower, so it has me a bit puzzled. Where I have it set now it will cut a 28mm wide mortise, just wide enough to leave 1mm of wood to clean off the side walls. In total, it may not be a new Mafell, but I really can’t complain seeing as both of these machines plus shipping was 1/3 the cost.

The hollow chisel mortiser arrived this morning, and had me really worried to judge by the look of the packaging. Despite the mangled look of this the bubble wrap underneath did its job except for a bent guide rod on one of the clamping fixtures.

This is Hitachi’s 30mm BS30SA. The ‘SA’ part of the model number means it can handle a 155mm long chisel. The BS30’s are more common and less spendy.  I’ve had the good fortune to try this model before, which is why I looked for it specifically, Makita seems to make good hollow chisel mortisers too, and they go for a bit less at auction.

I pulled this machine apart a bit to clean the old gummed up grease from the ways and guide rods and re-lubricate.

Now, 30mm is a big chisel to push through most any wood, so I tested on some red cedar after sharpening the chisel and auger. Western red cedar is cruel to less than a finely honed edge and it crushed on the end grain, anybody know a source for conical diamond hones big enough for a 30mm chisel? I bought this machine with square pegging in mind so next thing I need to find is some smaller chisels, but at least they can be found for sale without trouble. One thing I did try that worked quite nicely was using the chain mortiser to rough a mortise and then paring the side walls with the hollow chisel mortiser with the auger removed, keeping things really dimensionally tight and consistent.

These are the first power mortisers in my shop, I still prefer to make smaller mortises by hand and frankly I’ve put in the time  to get good at it, so tradition holds some sway with me. Up to now I’ve drilled larger mortises and then chiseled, which is by no means slow (ok, I’m still slow), but it helps to have the extra efficiencies when working by yourself trying to get your timber cut and assembled before too much dimensional change from seasoning.

What do you think, are these things worth it? I have a couple projects in mind and a good sawmill down the road that cuts local timber, a match made in heaven.


3 thoughts on “A Look at Hitachi Beam Mortisers”

  1. It’s so great to have you writing new posts! Finally, something good to read!

    I’ve been talking myself out of wanting one of the hollow chisel morticers, but it gets awfully difficult when you see them selling for $60 on yahoo Japan, haha. Even factoring in the >$200/each for shipping……you choose two beauties and I’m greatly envious. Have you already gotten a 6″ makita hand plane, or did you go straight for the big 12″ sucker?

    When I get dinged for the extra cost protective packaging, it’s usually been lots of bubble wrap and a bigger box (which invariably necessitates the more expensive EMS shipping option). Once I bought a 44 lb pile of old sharpening stones and in that case, Buyee’s protective packaging was plastic wrapped layers of expanding spray foam that locked each stone securely, form fitted into a huge cardboard box. They got here to Hawaii in 3 days, safe and secure, an amazing bargain really. Ironically, the stones had only cost me $100, but after the extra packaging requirement and express EMS shipping, the total was closer to $400, ugh! You will get a much greater value with these machines, no question.

    What’s in that leather wrapped saw case? Anything that is working out especially well? Inquiring minds……and no one else writes about saws, haha.


    1. 44lb of stones, that’s incredible! I still read your old blog posts, really miss your musings. I still read Chris Hall’s blog and savour the ocassional post from Ronin Daiku (his last post with the completed stacking tansu…hardware he chiseled himself…forged his own nails for said hardware, his incredible finishing ingredients, uh amazing!) And I also like Brian Holcombe’s blog, he seems real plugged in on the east coast.

      Not that you need the nudge, but just go ahead and get one of these beam mortisers, I’m happy I did and still cant wipe the shit eating grin off my face when I walk into my shop and see them. I kind of avoided the whole debate about which one to get by getting both, couldn’t be happier.

      I bough the Makita 6″ planer over a year ago when I was still digging the cellar hole and then that whole project stalled big time finishing the foundation walls because my mother was in a bad car accident and can’t set stone any more. I can find willing help with cutting and erecting the frame but for good masonry labour the budget has to be there. The Makita is sweet and smooth, but it has a habit of the blades slipping, a problem I noticed when I tried Mark’s Makita in Vermont. It looks like the 12″ uses carbide inserts which would solve that problem, but I can’t justify getting the big one, really I need a better 3″ planer, my cheap one has a real problem with clogging on green timber when squaring beams before the final pass or two with the Makita. Honestly sometimes I think I should just smooth with chona and call it good at that.

      I wish I had some nicer saws to show, I’ve only picked up a couple of basic ryoba. If I saw a 350mm ryoba I’d be all over that though. The nice saws from known quality smiths at auction are too good for me still and if I buy a lot of mixed rusties I’d have to buy a bunch of files and get a decent anvil…speaking of which I decided to put my blacksmithing efforts into education and signed up for a course at Frank Turley’s forge in Santa Fe this May. Coal forges, power hammers, three weeks of schoolin, care to join?

  2. Back in the day, I made a living with a chain mortiser. As a habit I would aim to be spot on with the width. There might be some clean up in order, especially due to knots which distort the blade path. You might be needlessly making more work for yourself if you intentionally undercut. I drove octagonal pegs into round holes. I can hope that you have clients who are willing to pay for the additional costs of square pegs. My clients were mostly cows.

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