Looking for replacement for a slot mortiser

[Mike Henderson]

I have a VERY small shop and when I build chairs, I always have to go to another shop to use the slot mortiser to cut my mortises. Is there a reasonably low cost tool that will do the same thing as a slot mortiser - maybe using the motor from a router?

When I say "reasonably low cost" I mean no more than $250 without the router motor.

Making jigs and cutting the mortises with a plunge router is much more difficult and error prone than using a slot mortiser.

My other choice is to make a "shop built" slot mortiser, using a router motor as the drive. It's easy to make the sliding table, and to slide the motor in and out, but it's more difficult to design a table that can be raised and lowered smoothly and accurately.

Any advice will be appreciated.

Mike

[Alan Turner]

Mike,

Some have used the newer Griz. horiz boring machine as a slot mortiser. The chuck is apparently not designed to withstand the lateral force of the stock movement, but users have not reported problems, to my knowledge. How stable and accurate it is in use is not known to me.
A second option if you want to build is that there is a fellow from upstate NY on ebay who sells good quality linear bearings and stainless rods at very favorable prices in diffrenct sizes, and with them you might be able to cabbage one together, using a router for the power. I talked to him once about the idea, and he is a knowledgable and inventive fellow.

I first saw a slot mortiser, demo'd by Alphonse Mattia, in about 1980, and since then looked for one on the used market as they are spendy. About $4500 new, although the Invicta is about $2700 if I recall correctly.
Took me over 20 years, but I did find an old Griggio, from the early 80's, and snapped it up, together with the rest of the tools and wood, all from an estate. They are great tools. I just don't understand why someone in the machinery business doesn't jump on this void and make one that is of good quality and affordable. They seem to be pretty basic in design. Good luck.

[Dan Racette]

Hey, if you are building one, there are several options, I am sure of it, but I can tell you that both woodcraft and LeeValley have Double-Ended Mandrels that you could belt drive. I believe that is how Ross Day had his setup in the Fine Woodworking book Tables and Chairs.

They run around $45

[Jamie Buxton]

A plunge router does a fine job of making mortises. For making chairs, you sometimes must make a specialized jig or two to grab the workpiece while you cut the mortise, but it isn't difficult. The router and the jigs require far less storage space than a slot mortiser.

[Mike Henderson]

Jamie, you're right about using jigs and a plunge router, but for me, using a slot mortiser was like taking drugs - once I used it and found how easy it was to cut chair mortises it was hard to go back to any other way.

I pay an annual shop fee for access to a large shop (as long as the tools are not in use). Once I have everything laid out, I can cut all the mortises on a chair in maybe 15-20 minutes, depending upon the number of mortises - and NO JIGS.

My problem is after I get home. Maybe I made a layout mistake, or I screw something up, or I forgot something, and need to cut some mortises again - I have to drive back to the shop to use the slot mortiser again. Of course, if it's just one or two mortises, I'll cut them by hand.

There was a plan in a recent FWW Annual Shop issue for a shop built slot mortiser but it didn't include plans for raising and lowering the table - you had to use shims to adjust the height of the stock.

Alan, congratulations on getting that slot mortiser. Too bad we live so far apart - I'd pay you a shop fee to use it! I'll check out that Griz boring machine, also.

Thanks for all your comments. If I find a good solution I'll pass it on to you.

Mike

[Ed Kowaski]

Alan, I had to smile reading about your quest for a slot morticer. Apparently we were in some parallel 20 year journey on that one :)

Finally one day just last year I was poking around in the dark back room corners of a tool store and there, barely noticeable under all the junk was the important parts of a slot morticer. The xyz table, a draw bar spindle and collet, all mounted in a frankenstien frame complete with motor and foot switch. 150 bucks later it was heading home with me!
WOOOOOHOOOOO :)

http://i5.photobucket.com/albums/y175/_riff_/slotmorticer.jpg

Micheal, building from scratch on the quick/cheap I'd used accuride slides. You can play some tricks with them if need be. Mount 2 at right angles and the "slide" will be vey rigid in all directions. Also sometimes possible to mount pairs so that when one is fully extended the other is fully retracted.

Ed

[Rick Lizek]

I first learned about horizontal slot mortisers from FWW about 25 years ago. Seems a shame they never really wrote much in-depth on the subject and continually only covered the chisel mortiser. They did cover the Wirth and Multi-router but failed to really investigate all the possibilities.
Once you use one it’s really hard to go back to the plunge router method and the use of loose tenons is what gives it the speed and accuracy. Some may balk at the loose tenon being less strong than the traditional tenon but I don’t see it as being signifigant enough and the only documented test is that one in FWW some years ago and it was kind of a lightweight test overall.

<O:p</O:p
$250 is a really tough call and you are scraping the bottom but there are possibilities.

<O:p</O:p
American WoodWorker March #106 had a slick router lift that used bronze bushings and steel rod from the local hardware store. The idea has great implications on other shop tools such as plunge router bases, sliding coping table for routers and shapers and of course a horizontal slot mortiser. Bushings run about $5 each and 4140 hardened ¾” x 35 rod is about $17 at Mcmaster.

<O:p</O:p
FWW Tools and Shop 1995 I recall had one that was cobbled out of aluminum T track, no height adjustment though. Pretty low budget.

FWW # 141. had a great one using accuride drawer slides and a simple, reliable simple pivot to adjust the height. A friend made one similar before the article was published and it was quite impressive. The height adjuster could be used on the one in Shops and Tools.

The Grizzly G0540, really a horizontal drill but have talked to several folks using it successfully as a mortiser. At $325 plus shipping there’s nothing close. The chuck has a 5/8” capacity. For the money the XYZ table is worth it alone so if one had to modify it a bit it’s still a good deal. BTW, conventional mortisers run at approx 3.600 rpm and not at 20, 000 rpm router speed. Having the added benefit of a horizontal drill and doweling machine makes this machine even more cost effective. There is nothing wrong with running that type of chuck. The issue is how the chuck is fastened to the arbor. Lateral forces can loosen the typical Jacobs taper but I have use a standard type chuck with a Jacobs taper on a mortiser by disassembling and pinning it on the shaft. I’ve spoken with of few of the G0540 owners and suggested using the heavy-duty loctite to secure the chuck and last I heard it seems to be working. There’s loctites you need a torch to remove and they really do work well.

The Robland/Laguna. Basically it’s the mortising table off the combo machine and sells for approx $600. This does include a real mortise chuck so one could rig up a few pillow blocks and a shaft and mount the chuck on it. Some threads would have to be turned but no big deal. A router is an option but I prefer the lower speed of a regular motor and it’s quieter. The router might be faster but again I like the option of a horizontal borer and doweling machine. I think the stand design they give could be improved upon and it doesn’t have to made of steel. BTW it’s not pictured on the website. You have to call and sak for it. It’s definitely a nice unit. I set one up for a friend. He loves it and he used the router and gave me the chuck. So something else to fool around with someday.
The Rojek would be the next contender. It’s about $1,700 last I checked and an optional spacer bar for 32 mm boring is available. It’s not meant to do line boring but it’s for the doweling feature. I’ve used this machine and I’d be willing to bet it’s pretty close to the Grizzly in fit and finish from what I’ve heard and seen of posted pics of the G0540. The Rojek does take some finesse with.

Then there’s the other DIY, the converted handmill. http://woodcentral.com/shots/shot52.shtml The one pictured is a bit scarcer. It has a collet type set up which would mean it’s pretty much ready to go with minor modifications. More common is a shaft type arrangement, which uses milling cutters that look more like shaper cutters. So the shaft would have to be modified for a chuck or collet. The speed is fine as is but most likely these machines would be three phase, which is no big deal but it does add a few hundred dollars more give ot take depending on the resourcefulness of the individual. Incidentally these machines can sometime be picked up for scrap metal prices or $500 thereabouts. Again it depends on the resourcefulness of the person.


I'm stopping here as we are way over budget.
<O:p</O:p

[Dave Tinley]

What about one of theses:

30405

Looks good for a good price.
You could put a router speed control on the router you mount to it, in order to lower the rpms. Plus, with a verticle raised panel bit, it would be easier to make them panels.

Dave

[Mike Henderson]

Rick, Wow, that's a really complete set of information - thanks. You must have investigated this area for yourself sometime earlier.

I'm going to investigate the pointers you gave me but the Grizzly G0540 seems like a really good solution. My goal of $250 was completely arbitrary - I'd be happy to pay $325, and it even comes with a motor.

I'm a hobbyist so the machine would not be used that hard. I'll keep in mind your pointers for making sure the chuck stays in the machine. I don't mind loctite'ing it in permanently.

Thanks a lot for all the information and for taking the time to type that in for me and everyone else on the site who's interested.

Mike

[Mike Henderson]

One comment about the slot mortiser in FWW #141 - When cutting mortises, I really like to be able to see the cut. With a slot mortiser, I mark the wood where I want the mortises to go and cut to my marks. With the mortiser in FWW you're cutting blind, just like on a router table. You have to calculate where the stops should go and set things up. One of the beauties of the slot mortiser is that you just have to clamp the wood on the table, set the depth, set the table to the correct height (which I check by moving the cutter up to the wood), and then make the cut to my marks.

If I was to build a slot mortiser, I'd want the motor to move in and out, and the table to move up and down (for adjustment) and side to side (for the cut).

But for the price, the Grizzly G0540 really looks good. I'm going to try to find one around here somewhere so I can really see it before I buy it.

Thanks again, Rick, for your help.

Mike

[Dan Forman]

Michael---Not sure if this is what you are looking for, but check out the Wooworker's Journal, December 2004. The article is tiltled: Build a Horizantal Routing System, by John English. The unit has X and Y sliding tables, and a motor mount which raises and lowers for height adjustment. I saw this at the library, made a not so great Xerox copy of the article for future reference.

Dan

[Rick Lizek]

On all the slot mortisers I've used you are cutting blind but it's no big deal. You mark the center line for reference and set it to the center line refernece on the table. The stops control the length of the cut. Sometimes it's just easier to do dowels instead of a mortise. We did put a mirror on one and it satisfied the requirents of the operator. You are going to restrict yourself with too many requirements. The FWW #141 as is or with the AWW rods and bushings is a simple. elegant way to go. I've seen pretty much all the other mortisers in the other mags and FWW #141 is the best by far.

Yes. I've spent many years using commercial ones and just seeing what others are available. In my opinion it's the best way to go for production and one offs. The speed and accuracy can't be matched by any other way. Looking at some of ther other posts you can tell who's never really tried a true slot mortiser. If they ever get a chance...
The horizontal router tables without the XYZ

There was a good post on www.woodcentral.com (http://www.woodcentral.com) of someone with the G0540. About a month ago I recall.
http://www.woodcentral.com/cgi-bin/messages.pl?read=252141

[Mike Henderson]

Rick, thanks again for the information. The only slot mortiser I've used (and I never looked to see who made it) is one where you stand (or kneel) on the left side of the motor and control two levers, one to move the motor in and out, and one to move the table left and right. From that position, you can see the cut being made.

What I do is mark my center line and the limits of the mortise. For the depth, you set a depth bar.

To operate it, I clamp the wood with an air clamp, move the motor with the spiral upcut bit up to the wood and center it on my center line by adjusting the table height, back off , turn the motor on, move in again to check if the cut is centered, then begin cutting using the end marks as my guides. The slot mortiser has limit bars but I find it much quicker to just cut to my limit marks. In all cases, I'm doing a one-off chair or maybe two - so far never more than that. I haven't used loose tenons - I still cut my tenon on the other piece of wood and trim it to fit the mortise. So if I went a bit too far or not far enough on the mortise, I fit when I trim the tenon.

Thank you again (thank you, thank you, thank you). I'm very impressed with your level of knowledge in this area and really appreciate you sharing that knowledge.

Mike

[Mike Henderson]

Just thinking - I wonder if I could do slot mortises on my drill press. If I built a sliding table which slid from side to side and moved front and back with a threaded bar, I could mount the spiral upcut bit in the drill chuck, set the depth with the limit on the drill press and cut by moving the work left and right and plunging with the drill press arm.

I'm talking cheap here and very small quantities.

Rick, any comments?

Mike

[Don Baer]

Michael,
You might look for something like this to add to your drill press.

30446


They're about $60 from Harbor Freight. They have a 7 1/2" travel in the X&Y Directions.

[Jim Becker]

Just thinking - I wonder if I could do slot mortises on my drill press. If I built a sliding table which slid from side to side and moved front and back with a threaded bar, I could mount the spiral upcut bit in the drill chuck, set the depth with the limit on the drill press and cut by moving the work left and right and plunging with the drill press arm.

I tend to think that the RPM is going to be too low, even at it's fastest setting. A horizontal router table is probably the easiest and least expensive, build or buy. But you will not have the levers. They bring a nice "ching...ching..." factor to the table, as it were... ;)

Of coures...you could upgrade to a Euro J/P (which is space conserving) as many of them have a slot mortiser available as an option. The only reason I don't have that option on mine is due to shop positioning as my particular machine would have it on the back...the new version has it on the front.

[Ed Kowaski]

Not Rick but I've done that, it works to some extent if the parts are not to large. Flat grain is easier then end grain. Added bonus, you'll find out how securely your chuck is attached.

How cheap do you want to go? In some respects the slider is optional for lower speed cutting tools. Krenov's first morticer was a hand drill clamped to a block of wood.

Ed

[Dan Forman]

Mike---I scanned a pic of the outfit from Woodworker's Journal I referred to. Do you think this might work?

[Mike Henderson]

Dan, Thanks for the scan. From what I can see, it appears to be similar to the one described in FWW - but I'll try to get a copy from the library to take a closer look.

Jim, You may be right about the speed. My drill press will got to 3,000 RPM. I think I'll put a spiral upcut bit in the chuck and see what it does.

Ed, Thanks for the encouragement. You're right about the table. I'll try some tests without the table just to see how it cuts and how easy it is to handle. If it works okay, I can add the sliding table after.

I realize that a drill press is a klug but it may give me a solution until I can afford and find space for the Grizzly horizontal boring machine.

Thanks everyone for your ideas, suggestions, and interest.

Mike

[Mike Henderson]

An update - I put a spiral upcut bit in my drill press and cranked it up to max speed (about 3,000 RPM) and tried first to plunge into wood, and second to cut a slot.

The test was not successfully. The drill press does not seem to be stable enough to cut successfully and the chuck kept coming out. I guess I could loctite the morse taper but overall, I did not feel safe doing the cut. Perhaps a combination of a secure sliding table and the loctite would work.

But another problem I encountered is that the work is supported on the back, rather than on the side, as it would be on a slot mortiser. This is a problem for certain chair parts, like rear chair legs which are not straight. On a slot mortiser, it's not a problem because the side of the chair leg is flat and straight and that's what you put on the table.

So I'm going to give up on the drill press and investigate the Grizzly line boring machine a bit more. I'd really like to see one before I order but I don't know where I'd find one around here. Maybe I can contact Grizzly and ask if they sold one in the LA area and then call that person to see if I can come over to look at it.

Mike