Project: 160 mortises-- router or bargain Delta mortiser @ Amazon?

[davidtu]

The Delta 14-651 Professional Bench Top Mortising Machine is on sale for $202 at Amazon currently. Minus $25 off will bring it to $178.

On Amazon: http://www.amazon.com/gp/product/B00...lance&n=228013

I have elsewhere inquired about getting a router to do 160 3/4" mortise cuts for a fence project I am working on. (FYI, cuts are 3/4" deep, 3/4" wide, 1.5" long into 2.5 x 2.5 (actual) Douglas Fir stock, for a garden fence.)

(Links: http://www.bt3central.com/showthread.php?t=20319 & http://www.bt3central.com/showthread.php?t=20320)

So... along comes this Delta Professional Mortiser. I've been advised that even a router will still need to have the mortises chiseled out to be squared. How much easier would this machine make my life and is it worth (to the general conscience) ~$1 / mortise to get the specialized machine?

I hate to admit at this point that I am a newbie and have no right getting such a machine. However, I do aspire to get into furniture making in the long run to help decorate a 1906 Craftsman Bungalow.

Thanks for any advice,
David

[just4funsies]

You might want to look into the HF morticer. I got one last month on sale for $99 (reg. price $159) plus used a 20% off coupon, for a net price of $79. It's not bad... no bells and whistles, but does the job pretty well. I sure buy one of them before I'd do 160+ mortices with a router!

[RodKirby]

Consider making loose tenons - that way you can easily rout roundover edges on them - makes the whole process MUCH simpler - no chiselling

However - you do need double the number of mortises.

[ajcraig]

160 mortises

160 mortises is a LOT of work either way. I would lean toward using a router only because it would be comparitively easier to set up a jig to make the mortising go faster. I've found it not terrible rewarding trying to "jig" on my mortiser. I love using it, but I've only done it on projects where I fully lay out each mortise. You don't have to square the mortise, you can round the tenon. That will be tedious, but on a fence project, you won't need close tolerances. Routing douglas fir will not tax any router 9-10 amps and up. Also, if you plan to continue in woodworking, you have a right to any tool that you can use for a project, and certainly find use for on future ones. (That's why we love this forum) Not very many woodworkers have only 1 router either. Other than avoiding 1/4 collet only, don't overly worry about getting the "right one". The kits are the best way to start, from the single speed hitachi @$120 on up to what your comfortable spending-only you know that, but I promise you, if you stay in woodworking, it will NOT be your last router purchase.

[Jeffrey Schronce]

I have the Delta 14-651 and it is an awesome mortiser and very highly regarded in the WW community.

I am again going to ask a little more info on this. So you already have this Douglas Fir? Why not go for a pre-cut off the self fencing material?

Regarless of above answers, you could do this project with the mortiser and I believe the mortiser is a great price right now. I don;t believe that your proposed mortises are deep enough for this job though . . . have you considered the amount of shrinkage/ expansion of the wood? What is the dimision of the wood you are using as runner between each post? Are you tennoning it down to fit this slot you are creating? Sounds like you are working with a 1.5 x .75 inch board. How many are going to run between each post? How tall are the posts? 1.5 seems awefully narrow and would seem to look odd with a normal 4 ft fence. Is this a lower fence, like in a garden to keep little bunnies out? I don;t think 1.5 x .75 material is going to fair well in the weather. Think warpage etc.

Again, mortiser maybe your answer here (I like it better than router unless you agree to do loose tenon, then that is quicker) but your project seems subject to potential failure. I am NOT trying to rain on your party, but at the same time that is a lot of work to walk out and find that the fence has fell apart or is warped, etc.

[davidtu]

Jeffrey, thanks for your consideration of my project. This is a really small fence, only 1.5' high. It is intended to add a little protection to a raised garden to keep out my beloved dogs who seem to like to dig and nibble plants. The garden is raised atop three stacked 6" railroad ties, making a total of 3' from ground level. The posts are custom made 2.5" square (actual). They are 2' tall and will be lag bolted to the topmost tie, 6" below garden soil. The horizontal elements are 3/4" x 1.5" x 4'. There are four horizontal elements to each bay, each supporting rather small 1" square 1.5' long pickets (7 to a bay, 5" apart).

I am not planning to tenon, by which I mean I will leave the full size of the horizontal cross sections. To be honest mortising is an after thought... I was originally just going to toenail them--as it turns out I cut the boards long (on purpose) for a little breathing room but now decided I'd rather have the neater appearance of the mortise joint... that and I apparently want to buy more tools and give myself lots of work.

I've attached a JPEG image of the fence. There is a larger fence behind it. I am not making that one! ;-)

I'm new to all of this and so I do appreciate your feedback. Hopefully given the small scale of the fence, the materials will not suffer as you have warned. What do you think, now that you have the full picture?

Many thanks,
David

[davidtu]

OK... so how does a mortiser work? It looks like a drill press, but can you move the workpiece across it like a router in a table or do you have to do a single stroke, move the workpiece again, do another stroke, etc. until you get the full mortise length desired? Do you need to make multiple strokes to gradually increase the depth (like I understand one would with a router) or can they go full mortise depth in single stroke? Uh, am I right in thinking there is such a thing as a stroke?! As you can see, I have no idea how it works... but I do like the square hole part!

I don't mind spending up to $200 for a useful tool. The Delta appears to be around $75 off w/ the clearance and giftcard... seems pretty good to me--especially since it seems so timely for my project.

[wassaw998]

It's a drill bit inside of what they call a square chisel. The bit inside the chisel is at a very close tolerance, so the bit does most of the work clearing out most of the material, but the chisel also does some work as the combo are brought down into the "to be made hole". Since the bit is housed in a square chisel, there is no ability to slide the cut as you describe. The only way to make a cut is "up -> down", so if you had a 3 foot cut to make, you would have to make it one "up --> down" cut at a time, if that makes sense. (Not like a router where you could slide the router across the 3' cut). Regarding multiple strokes, you'd set the depth stop, and go for the stroke, and I suspect on a given "up --> down" cut you may back out the chisel a few times, just exactly like you would using a drill press drilling a long / large hole.

[Ken Massingale]

David,
To solve your problem of the pups getting into the raised beds, have you considered getting the lattice from HD or Lowes and cutting it to 1.5 ft. high, trim the cut ends, and nailing or screwing that to the bed borders? Quick, not expensive and removeable if needed. And, I don't think it would look bad.
Just a thought.
ken

[Jeffrey Schronce]

Thanks for the JPEG it definately helps. Also thanks for describing the scale of the project.

The lag bolt below the surface is going to increase the structural rigidity of the project substantially. I would suggest putting the lag bolt in, placing the rails/runner in the post and then maybe putting a 3" screw in there to keep the post from moving. I would use Tightbond II in the mortise joints.

I think you can move forward with mortising the joints with either the mortiser or the router with a corner mortising chisel. I think they would be approxiamtely the same speed. If you go with the router make sure you build a jig to do this versus freehand (no way anyone can freehand 160 perfectly!). I have a few routers and the Delta mortiser. I would use the mortiser for this job.

Warpage is not as big of an issue seeing that you have all those little slat.
I would be my preference to go a little deeper on the mortise but if your material specs limit you to 3/4" you should be ok with gluing and posts that will not move.

[Hoyden]

I purchased the Delta Mortiser in Jan. from amazon for an arts and crafts bench I was making with 56 mortises, I love the mortiser, works very well. I made a jig to be sure all mortises were evenly spaced . Just keep your thinking cap on and have fun.

[LarryG]

Tough question, no easy answer.

Both methods (router, mortising machine) have advantages and drawbacks.

Your horizontal rails are 3/4" x 1.5" and you want to leave the ends full-size, requiring a matching mortise (as opposed to cutting a smaller, shouldered tenon on the ends of the rails). If you want the rails to remain rectangular, you need a rectangular mortise. If you use a router, that means chopping the mortises square by hand, with a chisel ... no fun.

That seems to point to the mortising machine, since it cuts square holes. But the largest chisel that comes with the Delta (I own the same model you're considering) is 1/2". You could buy a 3/4" chisel (an additional expense, could be significant, I've not checked prices) but these little benchtop machines probably don't have the beans to drive a chisel that large. So you'd most likely end up making two passes with the 3/8" chisel. That will add a lot of time since you'd in effect be cutting twice as many mortises.

Another issue is that a mortising machine is, as you say, a specialized machine. It makes beautiful square holes but that's ALL it will do. A router, OTOH, is the most versatile tool in the shop. Unless you foresee a definite future need for the mortising machine, a router will be your smarter buy for the long haul. The typical home woodshop needs a router long before it needs a mortising machine.

So. Let's see here.

Okay. All things considered, I'd buy a router, a 3/4" straight bit, and a 3/8" roundover bit. Use the 3/4" straight bit to cut the mortises, and leave the ends round. Use the 3/8" roundover bit to make a pass on all four long sides of the horizontal rails to shape them to fit the mortises. If you don't want to do the entire length, you could add interest to the fence's design by stopping the roundovers, say, 1" away from the posts.

With a simple jig to cut the mortises in the fence, using a router to cut them will go at least as fast as using a mortising machine; and doing the roundovers, whether full-length or stopped, will go a LOT faster than chopping the mortises square by hand. And when this job is finished you own a router, which is almost certain to be more useful on future projects than a mortising machine.

[wassaw998]

I got to the point where I am doing a lot of stuff that calls for, or could call for, a nice mortise and tennon joint. A BT Mortiser has been on my list for a while, and since I am sitting on a project needing a breadboard end for a table, and since I totally hosed up trying to use a router for the same, I've gone ahead and ordered the Delta BT mortiser. ...but, mostly cause Larry says it a good tool !

[davidtu]

Thanks to everyone for all your great insights!

Jeffrey, couple of questions: 1) can you explain where you suggest putting that 3" screw? Uh... be nice. ;-) FYI, I am putting two 4" lags to hold the post to the ties 2) I purhcased Liquid Nails Ultra Duty Poly... is the Titebond II much different? I could exchange.

Larry, I don't want to round the entire rail length. I am curious why you seem to suggest rounding 1" from the post (i.e. the last 1.75") rather than just the 3/4" that goes into it.

Guys, assuming I have to make a pass w/ the router to round the ends OR chisel out the holes, it seems like the Mortiser would be easier... except for the 3/4" bit not coming w/ the mortiser (and possibly overworking the machine?! -- Jeffrey do you agree it may not handle 3/4" bit?)

Regarding mortising bits... is there a difference bet. the type used w/ a drill press and for a mortiser? I want to make sure I order the right bit, if I go that route... which I am leaning towards.

One other thing... I guess I should meantion I have a 12" drill press, I've read they suck for use w/ mortising bit... but is it worth a try, especially if the bit is the same bit I'd need for the mortiser anyway?

Thanks!!

[LarryG]

Larry, I don't want to round the entire rail length. I am curious why you seem to suggest rounding 1" from the post (i.e. the last 1.75") rather than just the 3/4" that goes into it.

The extra 1" was chosen arbitrarily; it could be any amount. A 3/8" roundover bit cuts (obviously) a 3/8" radius. In order to fully round off the 3/4" of the rail that goes into the mortise, you'll have to cut that 3/4" plus that additional 3/8". IOW, you'll have a 3/4" long section that is fully rounded on all four "corners" plus a 3/8" long transitional section to the unrounded part. I don't think the transition would look well if it was jammed up tight to the post. The 1" extra that I suggested would move this transition away from the post some 5/8" as a design element ... you know, to make it look more like it was intentional.

And on second thought, that might be too much ... 1-3/8" total is probably more like it. That'd give you 3/4" of rounded-off tenon, concealed in the mortise; 1/4" of rounded-off tenon, exposed; and then the 3/8" long transition to rectangular.