First Blush Impressions

  • Advertise with us
Review by DynaBlue posted 10-01-2011 06:56 AM 12497 views 1 time favorited 14 comments Add to Favorites Watch
First Blush Impressions No-picture-s No-picture-s Click the pictures to enlarge them

Disclaimer: I’m not a professional reviewer and these opinions are mine and mine alone!

Retail Price: $149.99

I first saw this jig in magazine adverts about two months ago and have had a couple people ask me about the jig, but I hadn’t actually seen one until last night. I was able to procure the jig, spent last night reading the directions and checking out the General Tools Website videos, and today I tested the jig over several hours with the following results.

The jig specifies that it is capable of handling stock from 1/2” to 1 1/2” thick; so I took some undesignated project wood and spent an hour or so milling it flat and square in 1/2”, 3/4”, 1”, and 1 1/4” thicknesses. I ripped pieces at 1 1/2” (face framing), 2 1/2” and 4” wide. The manual states that you can do long pieces but doing so would not allow you to cut the tenons at the same time as the mortise. Not a big deal, but aligning the long piece on the jig as designed would be challenging at best. More on alignment later.

I unpacked the jig and familiarized myself with the basic controls while comparing it to the manual. The manual is well thought out, and I found no major discrepancies when applying the instructions to the jig. The main pieces of the jig consist of the following:
the jig itself;

reasonable quality guide bushings and centering cone; (Also a hex key and a bushing wrench which aren’t shown. The bushing set differs slightly from what you might be used to in that the center hub of the bushing screws in place vs. removing the entire bushing from the router. This is important when using a bit other than the 1/4”.)

a bit, which the manual states is a spiral upcut bit but instead is a straight flute cutter.

Also included is an alignment tool which I will show in a later picture.

The jig seems to be a decent quality bit of aluminum with adjustable heavy plastic guides for both the mortise and the tenon openings. There is a ribbed centering fence below the jig which allows you to adjust for nominal stock thicknesses in quarter measurements (3/4, 5/4, 6/4, etc). As shown in the picture it is set for 4/4 stock or 1” thick:

Opposite the centering fence are the face clamps which secure the workpiece against the centering fence. They are a ‘U’ shaped bracket with two knobs to allow you tighten from the back side of the jig. A minor complaint is that if you turn one knob too much more than the other you bind the face clamp and have to back off a bit. So I found you turn one knob a full turn and then the other. Turn the knobs until you’ve lightly secured the workpiece in the jig in preparation to align the workpiece both vertically and horizontally.

To set the workpiece to the proper height there are two positioning bars in each opening. In the above overview picture they are deployed in the mortise opening and retracted in the tenon. In theory the bars, when deployed, allow you to gently butt the workpiece up against them and ensure that you have correct vertical positioning below the top surface of the jig. In reality they flex too much to be of much value, and even very light pressure against them easily allows the workpiece to fail to square up relative to the top of the jig. That failure to square up is something that I didn’t recognize until I was setting up to cut my final set of joints; using an engineers square against the bottom of the centering fence corrected the problem (no, the picture shows BEFORE I used the square to er…square up the stock to the jig):

Also visible above is the method for aligning the mortise and tenon; they align in identical manner. Before placing the stock in the jig, you mark the centerline of the intended joint on the mating surfaces, and then you are supposed to align that line to the stamped marks in the M&T openings. The problem comes in that the workpice is about 3/8” below the surface that have the stamped marks, and parallax error can make it tricky to ensure that you are cutting both pieces in exactly mating places. Enter the alignment tool, a small metal guide which is supposed to allow you a better shot at both aligning the center mark with the jig and also assist in ensuring the joint length guides are the same. The problem with this tool is that it is nearly useless as the tab which extends down towards the workpiece still doesn’t get close enough to help eyeballing position:

Additionally, the tool is not long enough to reference against the sides of the jig so it is easy to misalign.

All of these can be overcome, but only once you know about them. They don’t seem to add to the EZ part of the jig.

The next step is setting the length of the mortise and tenon. A stamped arrow (visible in the above picture) on the jig allows you to set the graduated scale on the guides. All four guides need to be adjusted to the same setting. The black plastic guides are dovetailed into the side of the jig and seemed to stay mostly square to the edges. The aforementioned hex key is used to loosen and tighten the screws that lock the guides once properly positioned. A chart in the manual shows what the actual M&T length will be based on the guide setting vs. the bit being used. In general when using the 1/4” bit, the length will be 1/8” less than the guide states; 3/8” will be exact, and 1/2” will be 1/8” longer.

One of the last steps in prep is to set the depth of the plunge cut. The manual states you add 1/2” to the depth to account for the bushing (ie, a 1 1/2” plunge to make a 1” deep cut) and recommends setting the mortise slightly deeper to accomodate glue. Checking the actual length of a cut tenon showed it to be about 1/16” shorter than desired, again, probably not a big issue.

When cutting the mortise, you will always use the 1 1/8” bushing, but when cutting the tenon, you will switch the center of the bushing as indicated in the manual; a process that only takes about 15 seconds.

With my first workpiece in place, I set up the jig as instructed. I used a 1/4” bit, the 1 1/’8” bushing and a 3/4” piece of stock. The mortise went fine, but the tenon exhibited the ‘fence or flash’ which is mentioned in the manual as sometimes occuring:

The flash needs to be cut off with a saw, and the manual cautions you to be careful so as not to ruin your nice shoulder. I haven’t used any of the more expensive jigs, and they may do the same thing, but I can certainly see this as a potential nagging issue. So I decided that 1/4” tenon isn’t appropriate for 3/4” stock, and I set up for a 3/8” tenon. The recut seemed to go okay until the fit:

This is the first indicator of the positioning bars not actually squaring up the workpiece, and I attributed that to me probably placing too much pressure against one of the bars and causing the non-square result. The joint is also not flush at the end which is a factor of trying to adjust the mortise and tenon length guides. All the guides are supposed to be set the same (ie, all to 2 1/2” mark). However, the adjustment is done by eyeball, and if eyeball fails, you are supposed to use the alignment tool again. The diamond cutout in the alignment tool is supposed to allow you to match up to the stamped arrow and more precisely set the guide length. This works on one side of the jig, but if you look at the pictures the top edges of the jig aren’t equal; one is wider than the other. On the narrower edge you can either put the edge of the alignment tool against the jig which covers the scale (in hindsight I guess you can see through the diamond, but I still don’t see how this helps much if at all because there isn’t a good way to actually match the stamped arrow to the alignment tool) or you can align the diamond with the arrow without really registering against the edge of the jig so you’re back to eyeballing, the thing the alignment tool was supposed to help with. Additional testing of the jig showed that at the 1” minimum length setting the alignment tool was too wide and covered the centering stamp marks completely, forcing you to rely on eyeballs. Either the edges should be equal width or, alternatively, put all the template scales on the wide side of the jig instead of alternating narrow and wide.

Joint #3 seemed like it was going really well until I hit it with a square (I still hadn’t identified the flexing positioning bars yet) :

Knowing that any tool has a learning curve I continued on and went for #4. This time I paid close attention to the positioning bar pressure and tried again. The very first thing that happened was the mortise piece shoved out of the jig and notched the endgrain:

I started looking into why this happened, and what I found was that the entire jig body flexes as you tighten up the face clamps. What I found in retesting was when I cinched in the mortise piece and then the tenon piece, the mortise face clamps had loosened. I didn’t think I was tightening too hard, but apparently I was wrong. So it becomes a balancing act between tight enough to hold during routing and too tight. Probably some sandpaper stuck on the centering fence and the face clamps would be quite beneficial. This happened on a later piece of wood; so even when I was mindful of the problem, I was still sometimes unsuccessful at avoiding it.

I tried some 1/2” stock and ended up with the flashing issue; so careful attention needs to be paid either to matching bit/tenon/stock thickness or to your sawing skills after you finish routing:

I set up my 1 1/2” face frame stock and found out that the mortise side of the jig simply won’t clamp it because the face clamp and centering clamp don’t extend high enough to capture the wood. It seems that 2” is about the miminum width that the jig can work with; so if you’re looking do to M&T on narrow stock, you will either have to mill it wide and rip narrower after cutting the mortise or find another way to cut the mortise.

As I mentioned before, all tools have learning curves, and this jig is no different. Applying all the work-arounds I’d discovered, I was able to make a very nice fitting M&T on the seventh try. It was square, flush on the faces and ends, and loose enough without being sloppy. As they say in Eternal Optimist School, “Seventh times the charm!”

I would have to say that my final impression of this jig isn’t as favorable as I was hoping when I started. It is not a bad product and it will get the job done provided that you are willing to work around several limiting factors but it certainly isn’t an ‘unpack and go make a perfect M&T joint’ device. I have started brainstorming ways that I might increase the accuracy of set up while eliminating eyeballing, parallax and flexing bars. If I come up with something reasonable I’ll post more pictures. I am confident that ingenious woodworkers will start to adapt this jig and that feedback will hopefully lead to product improvements.



- At $150 it is much cheaper than other jigs designed to do the same thing;
- Does the job IF you are willing to work around several little problems


- Jig won’t cut face-frame sized stock;
- Frame will flex if face clamps are tightened too much;
- Clamping mechanism can loosen up if frame flexes;
- Alignment tool seems more like an hastily made afterthought rather than a helpful addition;
- Positioning bars are too flexible to be of much use in squaring up the stock without use of an actual squarel;
- Too much reliance on eyeball measuring for joints that must be precise;
- Flashing around tenons when using particular bits and stock thicknesses requires additional hand tool work


- Adhesive sandpaper on the centering wall and face clamp surfaces would improve grip without requiring excessive tightening;
- Redesign the alignment tool to: – Lengthen the center mark tab’ – Lengthen the cross piece to snugly fit between the jig rails; – Narrow the cross piece to allow use when the tenon length is set to minimum;
- Ensure both jig top rails are the same width to allow the alignment tool to work equally well on both sides;
- Put the length guide scales on the same (wide) side of the length template to allow the alignment tool to work ‘as is’;
- Include a chart in the manual specifying which bit/stock thickness combinations are most prone to flashing;
- Redesign the positioning bars to make them more resistant to flex and to be of more use in squaring up stock.

Thanks for reading,


-- Mistake? No, that's just an unexpected design opportunity....

View DynaBlue's profile


131 posts in 4036 days

14 comments so far

View Wolffarmer's profile


407 posts in 4084 days

#1 posted 10-01-2011 07:48 AM

Hey thanks for the very informative review. Not that I am in the market for such a jig but every bit of knowledge helps

-- That was not wormy wood when I started working on it.

View phil619's profile


35 posts in 4297 days

#2 posted 10-02-2011 12:22 AM

Great review. Thanks for posting it.

-- Building fine furniture in my driveway.

View Routerisstillmyname's profile


763 posts in 4355 days

#3 posted 10-02-2011 01:07 AM

THX for detail review and awesome pics.
These types of jigs for Mortise & Tenon are way too time consuming and the length of the stock is limited to the height setup. Accuracy is hit and miss at best.

-- Router รจ ancora il mio nome.

View Tennwood's profile


112 posts in 4027 days

#4 posted 10-02-2011 01:33 AM

Thanks for the review. I was really interested in getting one of these, but not so much anymore.

-- Jim, SE Tennessee, "Don't spare the kindling Dear, we have plenty"

View thedude50's profile


3613 posts in 3324 days

#5 posted 10-02-2011 09:08 AM

Daniel just reviewed the leigh fmt on our website, the review was a bit more pleased with this tool than you were with the general. Your review was well done since this is a comparable machine you may want to read this review too click here and or copy the link to your browser. I don’t think Daniel had the same problems with the flanging, i am not sure if it is supposed to do that or if the formula is bad for the tenon, any way you did a good job. i can telll you the one thing we do differently is we take days to learn all the problems and how to fix them before we do the review. That’s why we take so long to do a review we feel we have to know if its the user or the tool if its easily mastered. few things are perfect out of the box and you could have given it a week or two and worked out the bugs and offered us a complete review with your solution’s since your lay out is so good this one little bit of advise and you could be a pro at reviews.

-- Please check out my new stores and

View michelletwo's profile


2785 posts in 3861 days

#6 posted 10-02-2011 01:44 PM

now this is an informative & well done review. thank you.

View Pdub's profile


926 posts in 4026 days

#7 posted 10-03-2011 09:55 PM

Thanks, I just saw this in a magazine over the weekend and was wondering where I would get the money for one. Maybe I’ll hold off for awhile before spending $150.

-- Paul, North Dakota, USAF Ret.

View pintodeluxe's profile


6204 posts in 3659 days

#8 posted 10-08-2011 09:23 AM

I thought it looked too good to be true. Can you cut angled or compound angle M & T joints?
As far as the alignment tool – could you just make a little wood t-bar that extends all the way down to the workpiece for easy marking? I agree with you their alignment tool looks like an afterthought.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Woodowl's profile


19 posts in 3353 days

#9 posted 10-08-2011 10:31 AM

For 150 buy a decent chisel and a saw and cut those in ten minutes. Perfect fit

View Chipy's profile


374 posts in 3439 days

#10 posted 10-09-2011 03:23 PM

Thanks Dyanablue for the in depth review! I drooled over this jig thinking it would be a great alternative to buying a costly dedicated mortise machine/”dust collector”(joke)This jig had a odd coming out party and took a long time to come to market witch left me with a lot of questions even before this jig hit the shelves now I know why.I don’t do a lot of mortise work but would like the capability.You have saved me a lot of aggravation and dismantlement,thank you, this is just what this web site is all about!!!!! I kinda wonder how well those $800 +jigs perform????

View lcwood's profile


220 posts in 3610 days

#11 posted 10-26-2011 10:07 PM

nice review with pros and cons!

looks too good to be real and the cons me tell the real deal
tanks for save me 150 bucks !

View Gary Ferrini's profile

Gary Ferrini

3 posts in 4370 days

#12 posted 07-29-2013 01:31 PM

Wow. Thank you so much for an incredibly informative and detailed review.
This reviews saved me the trouble of buying one and finding out what you revealed here.

-- Gary, Shenandoah Valley

View Lumberpunk's profile


334 posts in 3183 days

#13 posted 04-18-2014 02:02 PM

I don’t know if anyone is still watching this thread but I have a question. I have just received my M/T jig and first impressions leave me a wishing I had read this review before buying. I haven’t even tried the jig yet but right away I am noticing a lot of slop between the guide bush and the mortising guide (between 1/64 and 1/32). I am wondering Dynablue if you experienced the same thing. I will be trying the jig today to see how it affects performance but it doesn’t give me hope.

-- If someone tells you you have enough tools and don't need any more, stop talking to them, you don't need that kind of negativity in your life.

View joejt's profile


53 posts in 4898 days

#14 posted 10-31-2014 07:44 PM

I have recently had the opportunity to try this jig, and I was able to make a test mortise and tenon joint. I like the quality of the jig, but I have a few suggestions for the designer who I know is following this blog.

I like the quality of the jig. The screw in bushings are nice and a necessity.

I read the review by Dynablue and share most of his observations. However, I had no problem with the set up fingers as he did. He was concerned about give/bending of the fingers and not getting square joints. I tried to duplicate his concern about bending, and found it would take a lot of force to do so. Just placing the wood firmly against the fingers, I was able to make a square joint. Also, the addition of the Squaring adapter should alleviate his problem of square joints and it is a welcome addition for making repeat cuts without measuring and marking each joint.

Suggested Improvements:

Better method for centering the wood front to back –
The front fence is calibrated based on sawmill references: 2 quarter, 4 quarter, etc. Note that not all boards are not going to comply exactly – some will be exactly 3/4” others may be over or under, for example. I think the front fence should have a crank, knob, or other means of adjustment so the work can be easily centered in the template window. However, if the wood is always oriented with the same face to the front or back, there is no need for PRECISE centering. It still would be easier to approximate quite accurately with a different means of adjustment.

I was going to complain about the lack of a settable stop for repeat cuts ,but then discovered the squaring/stop accessory. Seems the manufacturer is getting feedback and listening to it.

A clean-up in the directions:
“Set the Depth of the Router Bit” There is no need to reference from the router face plate. Simplify by measuring the protrusion of the router bit from the face of the guide bushing. This will determine the depth of cut in the mortise, and the length of the tenon. Eliminate the instruction calling for measuring from the base plate and subtracting 1/2”

Introduce the squaring/stop tool earlier in the instructions. Note: it is not included in the section of “What’s in the M&T Jig Kit”

Other Concerns:

Plastic template width adjusters. I am afraid that repeated movement and squeezing the set screw will wear out the plastic guides quickly.

-- joejt

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics