Author Topic: 2 "How To" Questions regarding compound angle cuts  (Read 1238 times)

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Offline Alt

  • Posts: 22
2 "How To" Questions regarding compound angle cuts
« on: May 21, 2022, 05:28 PM »
Hi,

Please see attached sketch! Dimensions are 36x36x45 cm. Angles are both 5 degrees.

1) how to cut the seat?
2) can I use an XL 700 for joining the legs? If not, how would you do it?

Thank you,

@Alt
TS 55, MFT/3, XL 700, Rotex 125, OF 1400, Carvex, table saw

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Offline ChuckS

  • Posts: 4260
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #1 on: May 21, 2022, 05:39 PM »
1) On the table saw crosscut sled if your sled is big enough with the blade tilted to the desired angle, otherwise use the fence. You may need to place the seat upside down if it's a left-tilt saw.  Cut with the bade raised to the max, and complete the notch with a hand saw, such as a Dozuki.

Alternatively, cut it on the band saw (table titled) and chisel to final specs. I'll probably use a hand saw, saw it close to line, and finish it with a chisel guided by an angle block.

2) You didn't give the thickness of the leg/seat. Use double/twin tenons if stock is thick enough. This sketch shows the concept of right-angle mortising on the mating parts:

« Last Edit: May 21, 2022, 05:55 PM by ChuckS »

Offline Alt

  • Posts: 22
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #2 on: May 21, 2022, 06:03 PM »
Thank you, @ChuckS !
The stock is 1 1/8".

If I understand your drawing, the XL reference is the beveled seat edge, except that I'd reverse the when going into the leg. Correct?
As far as the table saw ... I am running the seat on its side with a mitre and blade angle both at 5 degrees. So, raise the blade to the shortest height (bottom of seat) and then chisel clean! Right?

I suspect that I do not have enough thickness for two 10 mm dominos (once on each face). Are then two 8 mm enough for support?

I appreciate the quick reply.

@Alt
TS 55, MFT/3, XL 700, Rotex 125, OF 1400, Carvex, table saw

Offline ChuckS

  • Posts: 4260
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #3 on: May 21, 2022, 06:48 PM »
1-1/8"? Very skinny legs. May be even too thin for 2x8mm tenons. Would 1 x 12mm be better?

You also need to consider the racking of the chair, and orient your mortises vertically and in line with the racking.

I'd cut a mock-up joint, and try out the two options: 1 x 12mm and 2 x 8mm if in doubt. 
« Last Edit: May 21, 2022, 06:51 PM by ChuckS »

Offline Alt

  • Posts: 22
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #4 on: May 21, 2022, 07:41 PM »
Here is what I was thinking of, @ChuckS !

I think a can do 12 mm as well.

TS 55, MFT/3, XL 700, Rotex 125, OF 1400, Carvex, table saw

Offline Crazyraceguy

  • Posts: 2353
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #5 on: May 22, 2022, 08:03 AM »
There are a couple of ways to go about those notches without having to do hand work like chiseling.
They are effectively the same except for the orientation of the seat panel itself. So the choice comes down to the tools you have available really.
First is a table saw sled with a vertical support for clamping the part in place. Set the panel to one angle, the blade tilt to the other, cut one side of each notch, then reverse it all for the other side.
This could be done exactly the same way with a track saw, just cutting from above instead of the blade being below.
The Domino part is the conundrum. You cannot cut the mortices into both sides of a piece, with a notch, like that.
It won't go together like it would with loose aprons.
Strength is a relative issue. If this a small display table, plant stand, etc. it might be fine like this.
The bigger the top gets, the more need you will have to support the legs better. A lower apron will help a little, but tying them together with a lower stretcher would be the best. This would be especially important if it would be used as a stool.
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Offline ChuckS

  • Posts: 4260
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #6 on: May 22, 2022, 10:11 AM »
To cut the mortises on the notches:

1) Cut an angled block (same as the leg (out of scrap))
2) Cut the notches out
3) CA glue block temp. to seat
4) Set machine to depth (taking into account the block) and to the appropriate fence angle & height
5) Mill the mortise thru the block
6) Heat the block joint and knock it out.
« Last Edit: May 22, 2022, 10:19 AM by ChuckS »

Offline Alt

  • Posts: 22
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #7 on: May 22, 2022, 02:11 PM »
Thank you @Crazyraceguy and @ChuckS ! I appreciate the detailed help!

@Alt
TS 55, MFT/3, XL 700, Rotex 125, OF 1400, Carvex, table saw

Offline Crazyraceguy

  • Posts: 2353
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #8 on: May 22, 2022, 02:41 PM »
To cut the mortises on the notches:

1) Cut an angled block (same as the leg (out of scrap))
2) Cut the notches out
3) CA glue block temp. to seat
4) Set machine to depth (taking into account the block) and to the appropriate fence angle & height
5) Mill the mortise thru the block
6) Heat the block joint and knock it out.

It's not that you can't cut the mortise in the notches, with a DF700, you could very easily, but you can't install a leg in a notch with a tenon in both faces. They will interfere with each other.
CSX
DF500 + assortment set
PS420 + Base kit
OF1010
OF1010F
OF1400
MFK700 (2)
TS55, FS1080, FS1400/ LR32, FS1900, FS 2424/ LR32, FS3000
CT26E + Workshop cleaning set, Bluetooth remote
CT15
RO90
RO125
ETS EC 125
RAS115
ETS 125 (2)
RTS 400
TS75
Shaper Origin/Workstation/Plate
MFT clamps set
Installers set
Centrotech organizer set
Socket/Ratchet set
Pliers set

Offline ChuckS

  • Posts: 4260
Re: 2 "How To" Questions regarding compound angle cuts
« Reply #9 on: May 22, 2022, 03:12 PM »

It's not that you can't cut the mortise in the notches, with a DF700, you could very easily, but you can't install a leg in a notch with a tenon in both faces. They will interfere with each other.

Agreed given that the stock is only 1-1/8" thick. That's why the tenons should be properly oriented for the racking force.

If the notches and stock are in decent sizes, one can mortise the second set of mortises (on the sides so they're not seen from the show faces) as through mortises, and then plug the surfaces (like plugs for screws).