How would you hog out these open mortises?

[Randall J Cox]

I am building four patio chairs out of white oak (see pic as example). The arms are a full 2"x4" all the way around, top/bottom and uprights. I have bandsawed 4" in on 4" high wood for the open mortise (see pic) where the arms connect at 90 degrees. My issue now is how to hog out the center part with a nice flush back as the joints will be very visible. My 8" dado will only take out half of it using a tenoning jig as it will only raise up 2" above the table saw top. I have 16 of these 2"x4" boards 30" long, so that means hogging out the center portion 32 times (once on each end). I have an 18" band saw (MiniMax S45) and the motor got really hot yesterday cutting these open mortises. I will have to do the same to cut the tenons on 32 ends of the uprights which are also the same 2"x4" material but, thankfully no hogging out on these though. so how would you clean these mortises out and leave a nice flat back? i really don't want to do hand chisel work on 32 ends of white oak....I'm 73 and may not have that much time left - ha ha. (I could have saved my self a lot work by using 3.5" wood and not 4", maybe next time. Learning experience!) Open to any suggestions on how to hog out this center portion... Randy PS hopefully the two pics will show up right side up.
IMG_5115.jpgIMG_5184.jpg

[Derek Cohen]

Randy, I would use a fretsaw, and clean up with a chisel.

Begin by creating a chisel wall at the baseline, then fretsaw the waste. The chisel wall now offers a way to chop the last bit of waste without pushing back the baseline.

Regards from Perth

Derek

[Rod Sheridan]

Do you know anyone with a shaper?

A shaper can cut those bridle joints.

Of course so can a bandsaw...Rod

[Jim Becker]

First thing that came to my mind was a fretsaw, too. You have the room with the kerfs to use one if my eyes are not deceiving me and can then clean them at the visible edges with very sharp chisels.

[glenn bradley]

I would use a bandsaw before I took after thick stock like that with a fret saw. The curse of being a hybrid woodworker; I always see a powered way to take care of the plodding sort of tasks ;-) Square up with a chisel using all the time you saved with the bandsaw.

[Bill Dufour]

I wonder if one of those portable door lock mortice machines would cut deep enough . I would cut most of the waste away with a jigsaw or reciprocating saw first.
Bil lD


4+3/4 deep is the max
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[Bill Dufour]

It would have been easier to glue up the wood with the mortise already built in.
Bil lD

[Bob Jones 5443]

Randy, I thought the same as Derek and Jim when I saw your post. You could also consider cutting several more bandsaw kerfs into the space to be voided; that would make your sawing and chiseling task a lot lighter. You say your motor got hot: what blade are you using? You may benefit from picking up a sharp 3/4" 3 tpi blade.

I'm cheating with my bridle joints. I'm going to make my daughter a bed headboard. The cross section will be 2-1/4" x 2-1/4". I'm going to build up to that thickness by laminating three 3/4" parts. The joints will be made by just shortening or lengthening the middle member, and leaving a gap elsewhere as needed, to fit its mating part. I envisioned something like your design, but quailed at the thought of making even six bridle joints. Like you I want the joints to be smooth and invisible, and my skill set is not quite there yet.

Good luck with yours! Try the bandsaw kerfs.

[Mike Kees]

Third vote for a bandsaw. Skinny blade cut across on a angle from one side and then play to chew out as much as possible. A mortiser of some sort could also do this,even if you had to work from both sides. I do suspect chisel work is going to be required for clean up whatever you end up doing.

[Mike Kees]

Ok fourth vote. Bob was quicker on the draw.

[Bill Dufour]

Drill out the end then round over the tennon to match the drill diameter. Or square it up with a bandsaw and some chisel work after drilling.
Bil lD

[Jim Becker]

He's only needing to do the short waste cut based on the photo which shouldn't be a problem for a fret saw and would leave less to clean up than doing the angles and nibble dance with a band saw...but either will work just fine

[Randall J Cox]

Thank you for all the replies! I've been working on other parts of the project while pondering this issue. Actually just sat in my shop for a while, cooling off, 107 out today), and looking at each machine. I was trying to see it there was some other way to use one and get this done. I'm going to try saw kerfs but from my 12" chop saw. I used two 4"x4" blocks about 12" long and notched out about 1/2" deep and 6"long. Have one on each side of the board heading directly at the chop saw. I have two clamps holding them fast. With the 30" board heading directly at the chopsaw (back part resting on a roller stand) the chopsaw will cut kerfs almost to the line with my setup, all I will need to do is move the board side to side before (not during!) each cut. That should remove most of the wood. I'll chisel out whats left and take to the bandsaw and nibble away the rest. Once it get to within probably less than 1/8", I move board back and forth slowly to nibble the rest away to the line. I know the purists here will think this is all woodworking blasphemy but I'm going to try it. I know there are experienced woodworkers out there that this wouldn't even be an issue. I'm trying to get these chairs done so my daughter can still use them this summer. I don't work real fast with all the other things I have to do. They way I have it set up, doesn't look dangerous to me at all, and believe me i do consider safety. Still have all 10 digits and want to keep it that way! ha ha Randy PS And I don't know anybody with a shaper...

[Derek Cohen]

He's only needing to do the short waste cut based on the photo which shouldn't be a problem for a fret saw and would leave less to clean up than doing the angles and nibble dance with a band saw...but either will work just fine

Randall, I can read you avoiding handwork like crazy, looking at every possible machine way to do this task. But Jim and I are saying the same thing - the amount of sawing with a fretsaw is minimal. It takes a seconds to do. You can twist the fretsaw blade in the kerf and cut straight across. I am experienced enough to saw within a millimetre of the baseline. Chopping out the last bit of waste can be aided by a block of wood as a fence, or just undercut a little. All good.

The process is no different from removing the waste in hand cut dovetails, and I have done thousands this way ...



Regards from Perth

Derek

[Bill Dufour]

A big radial arm saw could do that. I would clamp the wood to the fence for the cuts.
Bill D
Want to buy my 16" de walt ras?