Tilting mortisers -- I think I'm missing something

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I've been looking at a few different models of tilting mortisers... and I just don't get it.
The Powermatic 719T http://www.powermatic.com/Products.aspx?Part 91264K&cat=P120 tilts the table to the left, so that you can cut a mortise like this (side view): ______________ __________ / / --------------------------------------------
The General International 75-075 http://www.general.ca/products/1_general/75_mortiser/75-075.html tilts the head to the right, so you can cut the same kind of mortise.
Likewise the Grizzly G0448 http://grizzly.com/products/Heavy-Duty-Mortiser-With-Stand/G0448 except that the head tilts left instead of right.
But what in the world is the use of cutting a mortise like that? I don't get it.
I understand that for chairs in particular, it's desirable to cut angled mortises in the legs, because chairs typically are wider in front than in back -- but these mortisers won't do that type of angled mortise. Angled mortises in chair legs need to look like these
http://furnituremaking.com/wordpress/more-chair-joinery/
and there simply isn't a way to cut those with these machines.
Grizzly even says "Simple adjustments allow the head to tilt up to 30? left or right, and the fence also pivots up to 30?, providing just about any combination of angles." Just about any combination of angles *except* those you'd need to make a chair, which seems to me to be the *main reason* you'd want to cut angled mortises.
I don't get it. What am I missing here? Why would you want to tilt the head, or the table, at an angle parallel to the *long* axis of what you're mortising? And what's the point of Grizzly's pivoting table? I just can't wrap my head around the purpose of cutting mortises at these angles. Or how I could use one of these machines to make a chair.
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On 1/20/2015 4:11 PM, Doug Miller wrote:

Well at times tilting the table is better than building a jig to tilt the work. Suppose you want to reinforce the mitered joints of a box with a floating tennon. I have a Delta mortiser and can't tell you the last time I used it. Well yes I can, Feb 2005. And I can count on my hands how many times I actually use this machine. The Festool Domino, a portable mortiser that I have now owned for about 7 years has cut in the neighborhood of 10,000 mortises for me. I can Assure you I had a use for the mortiser before I bought the Domino but the stationary mortiser was much too limited with what I could use it for.
Given the prices you are looking at on the links you would actually come out spending less money on the Domino and it will do a heck of a lot more than the typical stationary mortiser. If you are actually considering buying one. With the Domino you would certainly step up your game if you want to introduce more mortise and tenon joinery to your furniture. I have used the Domino probably 10 times more than my 20 year old PC biscuit joiner. The Domino seriously and accurately speeds up production and you basically adjust it the same way you would a biscuit joiner. Often there is no set up at all unless I am using thinner or thicker material. With a Domino I would say you could produce mortices at a rate of 10 to 1 compared to a stationary unit and the holes would be perfect in size and smooth inside.
If you are really looking, Festool offers a 30 no risk return policy...
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For something like a cabinet with a curved front, perhaps? That sort of work often has a straight (i.e. tangential) tenon on the ends of the curved pieces, which goes into an angled mortise on the sides. You don't want to cut the tenon angled because it's weak.
As Leon said, now-a-days most folk would probably use bisquicks and just cut the slots at an angle on one side.
John
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RIght, I know that about not making an angled tenon -- that's why you cut angled mortises in chair legs -- but that's exactly the same issue as the mortise-and-tenon joint between a chair rail and chair leg: these mortisers can't cut that joint. What's the use of a mortiser with a table (or head) that tilts in a plane parallel to the fence? Cutting the joint you just described, or a mortise for a chair leg, requires tilting either the table or the head in a plane *perpendicular* to the fence.

Festool Dominos, maybe. Biscuits as a substitute for mortise-and-tenon joints? I don't think so.
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On Wed, 21 Jan 2015 01:30:12 +0000, Doug Miller wrote:

I wonder if one could do the same thing on a mortiser as I did on my drill press. I added a plywood table hinged at the front which tilts perpendicular. When combined with the horizontal tilt of the underlying original table I can drill compound angles as in chair seats.
But figuring out the compound angle is a bear :-).
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OK, I wasn't following what you described in the original post. Now I see what you meant.
Yeah, I'm a little mystified too, unless you can rotate the fence and table 90 degrees it doesn't seem much use.
Only thing I can think you'd do with a head angled parallel to the board is thru mortises that are going to be wedged, so there's a taper for the tenon to fit when the wedge is driven home. Seems like an awful complicated feature for just that purpose, tho.
John
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On top of that, 30 degrees of tilt is a lot more than is needed for that purpose.
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On 1/20/2015 4:11 PM, Doug Miller wrote:

Could it be that the feature is intended for floating tenon joinery primarily, and therefore not taking into account an ability to orient the work piece in proper relation to the fixed cutting head?
IOW, is there an ability to position/clamp the work piece perpendicular to the fence, instead of parallel to it?
Looking at the PowerMatic, the clamp, as shown, is it fixed, or adjustable?
I design and fabricate a fair number of chairs using floating tenon joinery, might well be misunderstanding the problem as you see it, but I do cut a lot of compound angled mortises for floating tenons and the tilting table on my Multi-Router, although oriented on a different axis, allows much the same thing.
Not taking issue with what you see as a problem, just trying to understand it.
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On 01/22/2015 10:00 AM, Swingman wrote: ...

The clamp position is fixed, the table is on dovetail ways L/R to move workpiece relative to head.
IM(NSH :) )O, the manufacturer doesn't particularly worry about the application; the tool has the DOF it has and it's up to the user to figure out how (or whether) it'll fit the purpose at hand or jig to adapt the work to the tool.
It's the disadvantage of the stationary tool that is also it's advantage--it's a lot beefier and capable of heavier work, but less flexible than perhaps a router-based or similar that can have alternate angles of attack relative to the work table.
Similar to comparing a radial-arm drill press to a full-fledged dual axis mill. There are other industrial mortisers that do have additional DOF but the $$ mount rapidly.
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On 01/22/2015 10:40 AM, dpb wrote: ...

Oh, just an additional note...I no longer have access to the big PM that was available in TN so I got one of the little (non-tilting) benchtop Deltas (from before they went totally south 20 yr ago or so). I've done much with it including reversing the head relative to the fence which allowed setting it on the edge of the bench and do end mortises in the crosses of the barn door frames and decorative X'es in 8/4 x 8's. Another project used a cradle for the work to set an angle.
Don't think can do that with these larger guys, at least without a lot of trouble.
What I _wish_ I had was the old chain mortiser for more of the barn work that still need to do...
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On 1/22/2015 10:40 AM, dpb wrote:

Thanks, hard to tell from the photo.
That certainly limits its functionality.
Like you, I still use my old Delta mortiser of years gone by, mostly for through tenon joinery, and have even jigged it up a time or two to cut some angled mortises, but IIRC I cut angled tenons to go with them.
... one of the reasons I purchased a Multi-Router years back, and well before Festool came out with the Domino.
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No, there is not.

Fixed.

And that's the crux of the problem: it's oriented on a different axis. With these machines, the head (or table) tilts only in the plane parallel to the fence -- which means you can cut mortises in, for example, a table or chair leg that are angled with respect to the long axis of the leg but perpendicular to its sides. And that's exactly the opposite of what's needed: a chair needs mortises that are angled with respect to the sides of the leg, and perpendicular to the long axis so that the chair rails will be parallel to the floor.

Yeah, me too, still trying to understand.
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On 1/22/2015 2:59 PM, Doug Miller wrote:

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that I had not considered about the uses of the tilting head feature, but I still think it's necessary to tilt the table perpendicular to the fence also.
<quote> Hi Doug, First of all, thank you for your interest in our 75-050T Mortiser. To answer your question, you are correct, the most popular use of the tilting head would be in chair making. The back slats are never perpendicular to the saddle, they require a slight tilt to the rear to provide a more comfortable seat. Also, many times, the slats are splayed from the saddle to the top rail of the back. Stair makers also use this feature for spindle mounting. These are good application for the tilting head feature. I hope this has answered your question. Regards
Peter Kennedy Vice President General International Mfg. Co. Ltd. </quote>
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On 1/22/2015 5:05 PM, Doug Miller wrote:

Well there you go! ;~) But is the answer you wanted? Does that answer fill your particular needs?
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Well, it's half of the answer I wanted: it at least explains why they manufacture mortisers which tilt in a way that didn't make any sense to me. Now it does.
The other half is, why do so few manufacturers make mortisers that tilt in the other axis also? As far as I can tell, only Laguna and Baileigh are making machines that tilt both parallel and perpendicular to the fence.
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On 1/22/2015 9:08 PM, Doug Miller wrote:

If there is enough business for 2 that makes both of them happy and the big customers like to have 2 or more available just in case a CEO dies or some crazy time - burning of a production building... and the other company is there to provide their needs. Call it Insurance. It also keeps one they do use Honest because there is another.
Did a number of years in Marketing before moving into pure engineering.
Martin
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Doug Miller wrote:

Doug, What are you planning to make? -Bill
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On 1/22/2015 9:08 PM, Doug Miller wrote:

Good! Are you just shopping or are you looking for a mortiser that will do what you want on a specific project? I'm thinking that since these particular machines are relative expensive compared to the run of the mill bench top mortiser, you might as well get the one that has the most angles of tilt. Assuming that the adjustments are not a PIA to get right. Some drill press tables do the same and, my Delta does, and I don't look forward to resetting to perfectly perpendicular to the bit. Anyway...keep us informed on what you do.
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On 1/22/2015 9:08 PM, Doug Miller wrote:

You're right.
The use of this particular tilted mortise feature as explained in the email would work for roughly half of what would be necessary for a very limited chair design. A relatively simple design where the two side assemblies are mirror images, as they are here:
https://picasaweb.google.com/lh/photo/XDM6Oz1-_pZSSD13bPBFx9MTjNZETYmyPJy0liipFm0?feat=directlink
(more of a simplified and squared stool design, than a traditional splayed and angled seat design).
Not being a fan of angled tenons in chair making, and if the goal is to design/fabricate using a traditional chair design (with more involved compound angled joinery as shown below) the tilting "feature" of the mortiser arguably won't take you that far:
https://picasaweb.google.com/111355467778981859077/EWoodShopMissionChairReproduction2013?noredirect=1#
In that respect, the explanation in the email, as justification for the limited ability to tilt, is arguably misleading.
Particularly to a novice purchaser, purchasing in part based on the advertised feature, but not fully aware of what it takes to effect M&T chair joinery, fixed or floating tenon.
Not everyone would stop to think it out, as you have.
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