PC 4112 Half-Blind Dovetail Jig
by Jack A. Loganbill
http://thewoodshop.20m.com



Introduction


PC4112 A single purpose half-blind dovetail jig like the PC 4112 makes sense for those who want to make drawers and boxes employing half-blind dovetails without a lot of fuss. The jig is solid and produces a perfect half-blind dovetail joint everytime. If you're looking for a small production jig, the PC 4112 should suffice. If you plan on making tons of drawers day in and day out, consider the PC 5116 or PC 7116. These later jigs have cast iron bases and cam operated clamp bars. They employ a similar aluminum template as the PC 4112. The 5116 template accomodates widths up to 16" and the 7116 template accomodates widths up to 24".

I prefer the PC 4112 over the Woodstock Intl/Harbor Freight jig. I have used both extensively. First of all the PC 4112 is much easier to setup. The PC 4112 edge guides are stamped so that it references both the drawer front/back and side automatically. The Woodstock dovetail jig drawer front/back and side guides are separate. Second, the depth (side into drawer front/back) adjustment is much simplier on the PC 4112. The Woodstock requires that you adjust a stop bar. It can be done, I've done it, but it is a pain. Lastly, the aluminum template of the PC 4112 does not flex--the Woodstock template does, leading to uneven cuts if you're not careful. The advantage of the Woodstock jig is the cam-action clamping bars, though I doubt the plastic components would survive frequent use. I recommend the PC 4112 jig whole-heartedly to anyone wanting to construct drawers or other projects using Half-Blind Dovetails.

I also have used the Leigh dovetail jig for years. For through dovetails it is hard to beat. But I don't like using it for half-blind dovetails because of its somewhat lengthy setup and the fact that you machine one drawer component at a time. The advantage of the Leigh is that you have complete control of the tail/pin layout.

I recently sold our PC 4112 to a friend and purchased the PC 7116 Omnijig. A review is on the way. Let me just say that the Omnijig is the jig to end all jigs as far as milling fixed-spaced half-blind dovetails in a production environment. The accompanying video is excellent in showing one how to setup the jig and covers the optional features that I doubt I will purchase. I don't regret purchasing the PC 4112, for the money it is hard to beat. But if you want speed and 16" to 24" capacities, the Omnijig may the answer. Currently we are using the PC 7116 and Keller for our drawer and box construction. (By the way, most often I use a false front on my drawers. Consequently, a through dovetail jig like the Keller will do just fine for drawer construction and in fact a surprising number of professional cabinet shops use the Keller for their drawer construction.)

Cost: Less than $100.00
Manufacturer: Porter-Cable


What I Like About the PC 4112 Dovetail Jig


  • Consistently produces strong, well-fitting half-blind dovetails.

  • Relatively cheap.

  • Easy to assemble and setup.

  • Built surprisingly well, no flex in the template.

  • Includes several sets of edge guides to machine 1/2", 1/4", and rabetted dovetail joints.

  • Our PC 4112 came with everything you need to start dovetailing: four sets of edge guides, the 5/8" guide bushing, and the 1/2" 14° dovetail bit.

  • The edge guides have a built-in step to automatically space the side work piece the appropriate distance from the front/back workpiece. Other jigs have separate guides for the top/bottom and side work pieces which can be a real pain to set accurately.

  • When machining 1/2" dovetails you will use a 5/8" guide bushing which happens to be the inside distance between fingers of the template. Consequently, when machining, you simply push the router bit in and out of the fingers, there is no side play/cutting.

  • One setting (1/2" dovetail) works with a wide variety of wood thicknesses, basically 1/2" and up for all drawer components. In other words, with one setup you can machine 3/4" fronts with 1/2" sides, 1/2" fronts with 1/2" sides, 3/4" fronts with 3/4" sides, etc.
  • The template is fixed. No fooling around to produce half-blind dovetails.


What I Don't Like About the PC 4112 Dovetail Jig


  • Several times I have pinched my thumb (I have thick hands) between the top clamp bar and the knobs when turning the knobs. If I take it easy, I have no problem. But when in a production mode mindset I have a tendency to unloosen both knobs simultaneously and inevitably, I pinch a thumb. Ouch.

  • On a similar note, watch out for the template support threaded rod when tightening/loosening the front clamp bar.

  • The clamp bars are soft steel and tend to bend if not supported at each end.

  • For constant production work, consider buying the PC 4112's big brothers (PC 5116/PC 7116). They're beefier and quicker to use due to the cam-action clamp bars. The knobs are fine for a couple sets of drawers--but they're a pain if you're doing lots of drawers/boxes.

  • The template is fixed, thus you generally design the height of the drawer sides to match the spacing of the jig (multiples of 7/8").

  • The 1/2", 14° dovetail bit produces an adequately strong joint. However, some suggest that finished product is not as attractive as let's say, a 1/2" or 5/8" 7 ° pattern. I agree to a point. These joints are strong and look like the production joints you would see on Kitchen drawers at your local home center or KDA. However, if you're after the most attractive joints, consider the Leigh, AKEDA, WoodRat, or Keller (through dovetails only). With all that said, I discovered that you are not limited to the standard 1/2" 14° cutter! Click Here to learn more about cutter options!



The Bottom Line


The PC 4112, in my book, is the best buy in the Half-Blind dovetail jig market. There are a number of spin offs, RBI, Hartville that would carry the same recommendation.

Rating: out of 5!


 



Assembly


Assembling and setting up the jig should take less than 1 hour. The jig unassembled as shown in Figure 1. However, it goes together without any fuss. A few tips:
  • Follow the instructions in the manual, they're excellent.

  • Do not tighten down the lock nuts on the template studs. You will later adjust the depth of cut and use these nuts as the "stop".

  • Fasten the jig down to your workbench. I use two #10 sheet metal screws to screw the front edge of the jig to my bench. I don't bother tightening the back down.

Figure 1. PC 4112 Components

Figure 1


Setup


Follow these steps to setup the jig:
  1. Choose one of the four sets of edge guides. I use the #1 right/left guides all the time. However, rabbetted half-blind dovetails will require one of the other sets of guides.

  2. Place two scrap work pieces (at least 4" to 5" wide) in the front clamp, one on the left side and the other on the right side.

  3. Set the drawer side to drawer front inset (See Animated Figure 2):
    1. Place the template over the work pieces.
    2. Move the template so the cull of each template finger is between 19/32" and 20/32" from the front base of the jig (or the inside of the side work piece).
    3. Tighten the lock nuts against the template's slotted bracket. This sets the depth of cut or in other words, the depth that the sides will inset into the fronts/backs.
    4. When you make your test cuts, if the sides stick out from the front/back, increase the 19/32" value. If the sides inset too much, decrease this value.

  4. Set the edge stops (See Animated Figure 3) for correct size half-pin:
    1. Place a work piece (at least 4" to 5" wide) under the top clamp on the left side.
    2. Place the template onto the work piece and tighten it down.
    3. Line up the left edge of the work piece with the the inside of the leading left side (but right edge) of the template.
    4. Clamp the top work piece with the clamp bar making sure it is square with either the front or back of the base.
    5. Remove the template.
    6. Place a 3/16" bar (or a feeler gauge set to 3/16") between the left edge stop and the work piece and tighten the edge stop.
    7. Replace the template and scribe a reference line of the right edge of the template onto the work piece.
    8. Repeat Steps 1 through 6, for the right side of the jig.
    9. Compare the right side with the left side by placing your scribed work piece under the template on the right side. The scribed reference line should line up perfectly with the right side, left edge of the template.


  5. Place a 5/8" O.D. bushing in your router with a 1/2" (14 degree) dovetail bit in your router.

    router depth gauge

  6. Set the bit to cut 9/16" deep. The depth of cut defines the tightness of the joint. The deeper the cut, the tighter the joint. The shallower the cut, the looser the joint. Make sure you measure this from the router base, not the guide bushing base. I made a simple depth gauge block to facilitate setting this depth in the future:
    1. Mount a 1-1/4" or so Forstner bit in the drill press.
    2. Set the depth of cut to 9/16", or a little less.
    3. Drill a 3/4" x 4" x 4" plywood block at this setting in the center of the block. Drill another hole, but centered through one edge so that the hole is exposed.
    4. Check the depth gauge against your current router depth setting. If it is shy, adjust your drill press depth guage to drill the required amount.

  7. That's all there is to setting up the jig. These settings will work for a 3/4" front/back and any thickness of sides (1/2" - 1").

Animated Figure 2. Dovetail Socket Depth Setup

Figure 2
Animated Figure 3. Edge Guide Setup

Figure 3
Click Here to access a PDF File Containing Frames of Figures 2 and 3.


Using the Jig to Make a Drawer


  1. Rip and crosscut your drawer pieces to their finished dimensions. The length of the front/back pieces determines the width of the drawer/box. The overall length of the drawer/box is determined using the formula: length of side + (thickness of front - depth of socket) + (thickness of back - depth of socket).

  2. Dado the bottom of the front and sides to accept the bottom. I use a 1/8" kerf rip blade.
    1. Set the blade to cut half the depth of the thickness of the drawer sides and 3/8" from the bottom edge.
    2. Dado all sides and fronts.
    3. Move the fence another 1/8" or so to produce the final width to fit the thickness of the bottom material.
    4. Raise the blade to cut through the backs, and rip all backs at that setting. This allows you to slide the drawer bottoms into the drawer sides from the back of the drawer.


  3. Layout the drawer pieces, inside face up and mark them as shown in Figure 2.

  4. Place the drawer components in the jig inside up and out with the bottom edge of the piece against the edge stop. The drawer sides are placed in the front clamp, the front and back are placed under the top clamp.

  5. Before routing I make sure:
    1. The letters marked in the corners of the two work pieces correspond.
    2. The drawer side and front/back are even height-wise.
    3. The drawer bottom dado is facing up (drawer front) or facing out (drawer sides).
    4. The bottom edge of the drawer components are against their respective edge stop.


  6. Rout the drawer components. Begin by routing a slight cut across the side drawer component, right-to-left. Then cut the pins and sockets, left-to-right.

  7. I have been asked why I dovetail the back onto the sides (rather than use butt, dado, lock, or through dovetail joints). Simple, it's faster than any other method I know of that produces a quality joint and a square drawer. For instance, dadoing the sides requires time to setup the dado blade, mill the dado, and then crosscut the back to fit. Lock joints require even more setup and fooling around. Since the dovetail jig is setup, it only takes a a couple or minutes to rout the sides/back and you can crosscut the back equal to the front, saving time and ensuring a square drawer. In the past I used a through dovetail for the sides/back joint, but again, it is much easier to cut all front/backs to one dimension and use the single dovetail jig setup.

  8. Assemble the drawer by placing a small amount of glue in the sockets, insert the drawer side pieces into the drawer front, insert the drawer back into the drawer sides, and slide the drawer bottom in from the back. I nail the drawer bottom to the bottom edge of the drawer back. Assuming the jig is setup, I can rout and assemble a drawer in less than 10 minutes.

  9. I have been asked why I dovetail the back onto the sides (rather than use butt, dado, lock, or through dovetail joints). Simple, it's faster than any other method I know of that produces a quality joint and a square drawer. For instance, dadoing the sides requires time to setup the dado blade, mill the dado, and then crosscut the back to fit. Lock joints require even more setup and fooling around. Since the dovetail jig is setup, it only takes a a couple or minutes to rout the sides/back and you can crosscut the back equal to the front, saving time and ensuring a square drawer. In the past I used a through dovetail for the sides/back joint, but again, it is much easier to cut all front/backs to one dimension and use the single dovetail jig setup.

Figure 4. Drawer Component Layout

Figure 4


Additional Tips


  • Experiment with different cutters! Click Here to learn more about cutter options!

  • Use the Leigh 1/2" 14° 8mm diameter shaft router bits for less chatter.

  • Place a piece of wood, the same thickness (or slightly less) the drawer front/side under the clamp bars when machining work pieces less than 10" wide. Otherwise, the clamp bars will bend when you tighten the unsupported end down.

  • Make sure the template lies flat against the work pieces. It is very easy on any dovetail jig to get in a hurry and not seat the template completely down on the work piece. Of course if the template is not seated, you will see a gap between the end of the tails and their mating sockets.

  • Traditionally, you want the edges of the drawer front to start and end with a half pin. To determine drawer widths to fit this rule, simply measure between the centers of the template fingers, beginning with the edge stop. For the PC4112, design the height of your sides in 7/8" increments: 7/8, 1-3/4, 2-5/8, 3-1/2, 4-3/8, 5-1/4, 6-1/8, 7, 7-7/8, 8-3/4, 9-5/8, 10-1/2, 11-3/8. These are approximate widths--you can add 1/16" to 3/16" to these widths.

  • Solid wood, baltic birch plywood, MDF core plywood, and MDF machine very well for both drawer fronts and sides. Veneer core (VC) plywood works okay for drawer fronts/backs (sockets) but the plies disintegrate when milling them for sides (tails). If you must mill veneer core plywoods, you can minimize tearout by sticking some 1/4" plywood to the front clamp bar.

  • Make sure that your dovetail cutter is centered within the template guide bushing and make sure the guide bushing is concentric. If your bit is not centered in the guide bushing or if the guide bushing is not concentric, you'll end up with inconsistent joints, your drawer component top and bottom edges won't line up, and so forth. It is not unusual for a cheap template guide bushings to be out of round by as much as 1/32" or more. This may not sound like much, but it can drive you nuts when trying to machine a drawer or box so that all corners end up even!

    Frankly, template guide bushings are a poor choice as a template pilot where extreme accuracy and consistency is required. Dovetail cutters fitted with guide bearings are more accurate and less troublesome than template bushing-guided bits. Consider buying precision template bushings for dovetail routing. Precision bushings are available from Leigh, Hartville Tool, and other sources. You'll need a 5/8" OD bushing for the PC4112/PC7116.

  • I apply veneer iron-on tape to all four edges of veneer core plywood used for drawer fronts and backs. The tape machines well and the result looks like solid wood to the untrained eye (the grain direction is the tip off).

  • Make sure your work pieces are square and flat. I do not recommend that you attempt to use the clamp bars to flatten work pieces. Even though jigs like the PC 5116, PC 7116, or Akeda that have clamp bars that will flatten cupped work pieces it is not wise to do so as later you'll have problems when assembling the box.

  • Consider purchasing the Hartville Tool Cam Lever Upgrade kit for Half-Blind dovetail jigs (#10599). It works with the Hart jig and the PC 4112.

  • The design of the jig requires that you machine the drawer fronts and sides individually when making rabbetted drawer fronts.

  • The 1/2" dovetail settings work with sides 1/2" thick and up and drawer fronts/backs, 1/2" thick and up.

  • Remember, inside out on all cuts. In other words, you cut the drawer fronts/backs/sides with inside up/up/out!

  • Consider dedicating an old or inexpensive 1 HP router for the jig.

  • Don't rotate the router as you're machining the joints. The router base and template guides are not always perfectly centered with the router bit. Any slight imperfection here seems to multiply several times which results in poorly fitting joints.

  • Use sharp bits to reduce tear-out and uneven bottoms.

  • Use eye and ear protection. Unlike shaping operations which usually only take a few minutes, machining joints for cabinet drawers can take hours of continuous router use. Protect your eyes and ears!

  • Wear a smock to facilitate casting off the tons of chips that are thrown back. Consider purchasing the Leigh RVA (Router Vacuum Attachment). One of the best features of the AKEDA dovetail jig is its ability to collect 90% of the debris.

  • Copy the manual and keep it near the jig.

  • The March/April 1993 Issue of Fine Woodworking ran a great article by John Lively about making Drawers using the $100-type Half-Blind jig. The best article I have found on the subject. It pretty much covers the subject soup to nuts.


Template Guide Bushings


Guide bushings (also known as collars or a guide bush) are extremely versatile and indispensible for many router operations. However, I have learned the hard way that guide bushings can be a source of fit problems when used with dovetail jigs, especially combination jigs like the Leigh and the AKEDA.

I have found two common problems with guide bushings:

  • They are often poorly machined. Their diameter and out-of-center tolerances vary greatly. I have guide bushings that are .030" out-of-center!. The best bet is to purchase precision guide bushings from Leigh, AKEDA (through Woodcraft), or whomever. Leigh offers precision 7/16" and 5/8" OD bushings, AKEDA offers a 7/16" precision bushing. The 7/16" OD bushing is the most widely used bushing with Leigh and AKEDA dovetail jigs. The PC4112/PC7116 use the 5/8" OD bushing. Note that for through and half-blind dovetails, the guide diameter is not super critical on the Leigh, since fit is controlled by moving the pin template out/in (through dovetails) or by raising/lowering the bit (half-blind dovetails).

  • Even if you have precise guide bushings, depending on your router, it may be difficult to center the router bit perfectly within the guide bushing. Perfeclty centering the router bit to a guide bushing is easier said than done. For instance, Porter-Cable routers mount their base to the router using flat head screws. As you tighten the screws, they center themselves in the base, drawing the base to "their center". Thus trying to center them is almost impossible. Some Bosch bases (1617 for instance) are mounted with pan-head screws, which do allow for some adjustment. However, you still may not be successful in perfectly centering the base, bushing, and bit (even with their centering cone).

To determine whether your bit is centered in the guide bushing, simply lower the bit into the bushing, rotate the bit, and look to see whether the tips of the bit are centered within the bushing for an entire rotation. Since a dovetail bit is angled, you can lower it into the guide bushing until it barely touches--just make sure to rotate it backwards. Or, better yet, perform the following: Or, better yet, perform the following:

  1. Mount the guide bushing and a straight bit in the router. The straight bit diameter must be less than the OD of the guide bushing.
  2. Setup your DT jig guide fingers to cut tails.
  3. Clamp a test board under the tail guides.
  4. Run the router through several guides.
  5. Visibly inspect the cut to determine that the cut is centered within the tail finger space. If it is centered, you're done.
  6. Otherwise, loosen the guide bush, rotate it 1/4 turn, and tighten it again.
  7. Repeat these steps until you get a satisfactory cut. You might want to mark the face of the guide bushing and router base to simplify this procedure next time around.
  8. If you cannot get the bit to center with the guide bush, try another guide bush. If you still have problems, you can try centering the base of the router/guide bush to the bit, but again, this is easier said than done.
  9. If you cannot correct the off-center problem, you might lessen the problem if you rotate the bushing so that the greatest deviation faces away from the jig (towards the operator). Then, make sure you keep the router facing the same direction as you rout the dovetails.



Dovetail Jig Stabilizer Table


Wood Magazine has published a free project to build a Dovetail Jig Stabilizer Guide. I have not built it but can express the need for such a table. R.L. Mott sent me some photos of his stablizer table/guide. Note that RL added some T-Track to improve on the Wood Magazine design:

RL Mott Wood Mag Stabilizer Table-a
RL Mott Wood Mag Stabilizer Table-b
RL Mott Wood Mag Stabilizer Table-c


Alternatives and Other Jigs


Don't discount making TD joints by hand or the hybrid method employing both the bandsaw and hand. If you're not doing a ton of TD joints, doing them by hand makes sense. If you're a novice at making TD joints by hand, buy or rent the Dovetail a Drawer video by Frank Klausz. Actually, this video teaches alot more than just dovetails. I found his general woodworking techniques to be very enlightening.

I came up with a chart comparing the Keller, Leigh, AKEDA, and PC Omnijig dovetail jigs. Click here to view it.

Here is a run down of Dovetail jigs you might consider:

  • AKEDA DC-16 Through and Half-Blind Dovetail Jig
    The AKEDA DC-16 from AKEDA Jigs Incorporated is the new guy on the block and certainly is a must-consider dovetail jig. Without any adjustments, the jig produced flawless, variably-spaced through dovetails for a box on my first try. I had the same experience with my first drawer. The jig comes through on its promises: no adjustments, excellent dust collection, virtually no setup, dovetail layout is easy and repeatable. It is quite simply a joy to use. Also, I like the geometry of the dovetails. They're more aesthetically pleasing than most machine-produced dovetails. Woodcraft handles the distribution of the AKEDA DC-16 for the U.S.

  • Leigh D4 Through and Half-Blind Dovetail Jig
    The Leigh dovetail jig Leigh Industries, Ltd. Is considered one of the best jigs on the market. I have had one for many years and like it for through dovetails. Leigh offers an extensive array of accessories that allow you to mill mortise and tenons, a variety of box joints, and decorative joints.

  • Porter Cable 16" and 24" (5116 and 7116) Dovetail Jigs
    The Porter Cable #5115 and #7116 jigs run $350 and $400, respectively. They are among the most robust jigs on the market. Porter Cable offers a variety of optional templates to compete with the Leigh as being the most versatile dovetail jig available. Someday we'll get around to publishing a review on it.

  • Porter Cable 12" 4112 Half-Blind Dovetail Jig
    The Porter Cable #4112 dovetail jig runs about $100 and is for my money, the best HB dovetail jig around. Click here to read my PC 4112 review.

  • Keller Through Dovetail Jig
    The Keller is considered by some as the easiest-to-use through Dovetail jig. I agree! Models run $150-$450. I purchased my Keller 1601 from Seven Corners Hardware for $189.00, which is considerably less than the show price ($209) or the suggested retail price ($249). Check out the Keller web site! It provides some great info and a gallery of work from Keller users!

  • Woodrat Dovetail/Joinery Jig
    The Woodrat is perhaps the most unique dovetail (joinery) jig on the market, and thus appears to have the largest learning curve. I have not used the jig, but it gets high points for versatility and creative/artistic capacity. Setups appear to be more complex than typical jigs. Runs in the neighborhood of $500.

  • RBI Wood Tools
    RBI sells a PC 4112 look-alike for $100.

  • Hartville Tools Model 12378
    The 12378 is another PC 4112 look-alike for $100. Hartville sells aftermarket cam-action clamps for the 12378 that also fit the PC 4112.

  • Woodhaven Dovetail Jigs
    Woodhaven sells a variety of dovetail jigs including their new top-of-the-line jig that can be used in the conventional mode or on top of a router table.

  • Sears Craftsman Dovetail Jigs
    Don't laugh, my father uses one of the cheaper models with excellent results. I recently gave him my old Woodstock Intl jig so he might retire the Craftsman, but don't count on it.

  • Woodstock Intl Half-Blind Dovetail Jig W1099
    This jig, also sold by Harbor Freight (Central Machine) and others, runs between $40 and $60. It works pretty well.

  • Katie Jig
    A relatively new jig that has received good reviews. It runs $250 plus. Marc Sommerfeld demos the Katie at the Woodworking shows. Impressive in that you can clamp a tail and pin board in the jig at one time (given you're cutting them on a router table). This ensures the alignment of the top/bottom edges and could be a real time saver if you had a two router setup like Marc Sommerfeld has at the shows. One drawback I saw in the demo is that the tails/pins top/bottom orientation is swapped on each end, unless you had two setups. If you get a chance to attend the WW Shows, look at the side of Marc Sommerfeld's drawers and you'll see what I mean. Functionally sound, but......

  • Stots Dovetail Template Master
    You use this template master to make dovetail and box joint jig templates. You can use it to make templates of virtually any size. It runs about $50 plus another $30 for the router bits if you don't have them. I want to try this tool, but I just have not had the time to fool around with it. Review coming soon.

  • Incra and Jointech Router Fence Incremental/Positional Jigs
    I would not consider the Incra and Jointech jigs for production work, but they work well if you are up to the setup. They work as advertised, but are time consuming to setup and use compared with dedicated dovetail jigs. For what it's worth, I prefer the Jointech positioner over the Incra. The Jointech is more roubust, uses leadscrew technology instead of the incremental racks, templates are easier to use, provides built-in centering, and their fence construction and design is excellent.

  • The $19.99 Half-Blind Dovetail Jig
    The Popular Woodworking September 1999 issue ran an article on a $19.99 half-blind dovetail jig. Click here to view the article in PDF Format. The author (Troy Sexton) explains how to make a simple router template to machine the pins. The tails are cut on the bandsaw. The price of "$19.99" includes $11 for a 23/32" diameter template guide and $8.95 for 1/2" 14 degree a dovetail bit. You probably already have these items. The simplified process:

    1. Rip a 5/16" thick template the same width as your drawer pieces.

    2. Use a dado to cut notches on one end of the template. One notch per tail.

    3. Clamp the template to the back side of the drawer front.

    4. With your router sitting on top of the template, run the router in and out of the notches.

    5. Use the cut pins to layout the tails.

    6. Cut the tails on your bandsaw.


    Questions


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