Jobsite Table Saw Router Extension

The same basic principles outlined here can be applied to a cabinet saw as well, but this post focuses on the portable jobsite variety. That tenet, portability, is largely why a table saw router insert makes so much sense here. I really don’t want to take up even more precious space with a dedicated router table, plus this way I can easily move and deploy two important tool stations with one action. Ah, the life of the driveway wood worker!
My table saw and router are both Bosch models which happen to be best-in-class contenders for these particular tools. Just about everything else in my tool chest is Dewalt but these Bosch models were very deliberate purchases based on overwhelmingly positive community feedback. I can personally attest, the hype is real.

Core Components

The jobsite saw I’ll be modifying here is the Bosch 4100-10 (10” Gravity-Rise Worksite Table Saw). My plan is to remove the right side extension table and replace with a custom router insert: Link



The only non-standard feature I added to this saw initially is the Bosch Outfeed Support Assembly which doesn’t interfere at all with my router extension insert. There is also a left side outfeed assembly which I may add at some point later: Link. My general feedback on the outfeed quality and functionality is very good, although you waste a bit of the shipped components since Bosch packs parts for two different saws: Link



My router is the Bosch 1617EVS which is a variable speed model generating 2.25 HP @ 12 amps. I purchased as a kit that includes both a plunge and a fixed base, along with collets for both 1/4” and 1/2” bits. The fixed base is what I used to attach the router to the insert: Link



Here is the end result, want to see how I built it? Keep reading:

Parts List

• 3/4” MDF half sheet: Link
• Rockler Pro Plate (Model A): Link
• Amana 5/8” straight cut bit: Link
• PowerTec T-Track (2 x 24”): Link
• PowerTec 5/16" T-Bolt kit: Link
• 4 x 5/16" zinc carriage bolts + washers
• 2 x 5/16" 3-prong T nuts (for plate)
• 12 x stainless flat head screws
• 1 x 1/8" x 2" steel bar 
• Minwax fast-drying oil-based poly: Link
• Minwax Past Wax: Link
• 3M Rugged Comfort Quick Latch Respirator 6503QL: Link
• 3M 2097 P100 Particulate Filter Pair: Link
• Titebond III wood glue: Link
• Dasco Pro Cold Chisel kit: Link

Cuts and Prep

Why MDF you may be asking? A couple of reasons, first it's relatively cheap, it's super easy to work with having no grain pattern as it can be cut in any direction, it glues up strong very nicely without need for fasteners and lastly it's dead flat which is important for this particular use case. The image below shows the 5 parts for the fence which will attach to the stock Bosch table fence directly. Plus the triangular supports and the support plate to round out the cut list. The general idea here was to create an insert that sits between the table slide rails and a fence slightly larger than the width of the table. This is 100% custom and can be applied to any other similar jobsite saw.

One quick note on working with MDF. Unless you have a stellar air filtration system you really need to wear a respirator. The MDF fiber particles are extremely fine, much like powder and will get everywhere, especially into your nose and lungs. I linked the 3M gear I use above which works incredibly well for me on all woodworking projects.




The cut image for the router plate got corrupted so sorry that's missing, but you'll be able to see in later photos what I did there. The length of the piece is from table rail to rail and I made it wide enough to house the plate, a handle cutout and a T-track rail.I used 6 support pieces on the underside which I'll show a bit later.

Router Plate Insert

I chose the Rockler Pro Plate as its aluminum which is a strength upgrade from many of the molded phenolic you will find for sale. I read several anecdotal accounts that these molded plates will sag and warp over time due to the weight of the router. No thanks, do it right with a metal plate!

Once the basic shape of the insert is cut, I created a simple template to cut the indention for the Pro Plate. Find the location on the board you want to the plate to sit, then surround with identical height scrap, hold down with double-sided tape. You want these pieces tight as possible to the edges of the plate. In hindsight using MDF around all 4 edges would have been better but what I did worked out ok.




Remove the plate and insert a center square piece which will be used by the router to rest on as it completes its task. Some people leave only a very tiny lip around the edge when doing these. A bigger lip equals more strength but also you really only need enough clearance for the router and base itself. I'll explain further just ahead. Set your plunge router at the exact depth of with width of your plate and route out the lip. Once the lip has been created, remove the center square and cut out the center piece of the board with a jig saw.




For the front T-track slot I used the plunge base with the Bosch Deluxe Router Guide. I HIGHLY recommend this part as a worthy addition to the tool box. The edge the guide glides on needs to be straight and true, if it isn't, your cuts will be mirrored imperfections. For this step, I marked the depth I needed for my rails on the side of the work piece, then plunged the bit real-time to the proper depth.




I needed to do a little flattening of my lip to get the plate to sit perfectly flush. I really don't want to mess with leveling screws in the corners but that's ok if you want to. I found that hand scraping with a chisel was a good way to remove material. Sanding just doesn't work very well with MDF and takes way too long. Check your level by using an MDF scrap sliding from the board surface over the router plate. If the plate is too high the scrap piece will knock on the edges. Keep scraping until perfectly flush.

So far so good.




Next I cut out the handle and pop-up notch to match the original extension wing that I removed from the table. Mark carefully, then cut out with the jig saw. I then softened the edges a bit with the rotary sander. This is similar to factory finish on the metal table edges.




Moving on to the underside... Next, I drilled holes in the side support pieces that will ultimately mate up with the bars to slide into the table rails. I don't have a drill press yet so used a block of maple and walnut with a true 90 junction that I used to drill straight holes. In lieu of a proper drill press this works well.




Here is a look at the underside and how I did the support pieces. 2 for each of the long runs, 1 on each end drilled for the metal bar that will slide into the table rails with a bit of overlapping between the ends and side pieces. I used no fasteners here at all, just glue and clamps which worked extremely well with Titebond 3. One thing to keep in mind here is that MDF is highly absorbent, especially on the ends, so any glue cleanup that you would normally do with a wood glue up won't work as well here. Some of the glue is going to get absorbed and won't wipe up well. I had no issues with adhesion on the ends either. You will read that some people go to careful lengths via multiple glue coats to maximize adhesion when attaching MDF end pieces. I really had no need to do that.




Using my trusty router guide, I cut a clean edge on the 2 sides to match the cuts in the metal table top. Now the tricky part, lining up the bars to attach this thing to the table. With the insert in place and leveled, I slid the bars into the table rails and marked the holes from the underside for drilling. I also marked the bar length for cutting at this step which I did with my jig saw and a metal cutting blade.




With the holes marked I used my "drill press" and a drop of oil for the bit to drill holes. Make sure your bits can be used to drill metal!




Because I intend to attach the bar to the insert using carriage bolts, I need the holes in the bar to be square so they will sit flush. This part is rather crude but it worked. Using a cold chisel, I flared the corners on each side of the holes, then with the bar securely clamped in my vise I knocked each side flat with a 3lb hammer. The best way to do this is to line up the edge you want to remove flat just above the vise jaw. Good work out on this step. Be careful here because the cold chisel will put gouges in your vise!




Ok so I'm finally done making changes to the insert piece and can start on finishing. Using a 50/50 mix of mineral spirits and oil based poly, I saturated the entire piece as much as I could using an old sock, 7 or 8 coats at least. This thinning will cause the poly to soak deep into the fibers adding strength and resiliency. After this dries a few hours I'll add several more coats then finish with a full strength coat a day later. Make sure to do some light sanding between coat sessions, 400 grit will do.




If you have the Bosch 1617EVS like me and want to use the Rockler Pro Plate, one small adjustment needs to be made to the plate. One of the cool things about this router is that the static base includes a height adjustment capability, built in. No need to buy one of the expensive (but awesome) JessEm router lift kits. But, unfortunately, the Pro plate doesn't have a hole for the adjustment key, so you will need to drill one. Luckily this is aluminum which is easy as butter to work with.
Here's what I did to figure out where to drill the adjustment screw hole. I inserted screws into the 3 holes of the static base that will ultimately attach to the Pro plate. I then found a random screw of similar height for the adjustment screw and inserted that into the adjustment hole. Lining up the 3 pre-drilled holes on the plate, I was able to mark where the adjustment hole needed to go. Pencil around the screw head is all that's needed here.




Mark the center of the hole with an auto center punch and drill the hole using a bit of the same diameter as the height adjustment tool that came with the Bosch kit. Aluminum is so soft you don't even need to use oil to drill, but it won't hurt anything if you do. That small lone hole below is mine.




Check for clearance, perfect.




Next I secured the Pro Plate to the insert using my pronged T nuts. Mark the location with the plate in the insert and drill to match the diameter of the nut. Insert from the bottom.




The plate will come with the right size screws in black for the corners. Screwing these in will tighten the pronged T nut from the bottom. I also cut to the T-track to length and screwed down with stainless flat head screws. I cut the track in a way to ensure the screw holes were as close to the edges as possible to secure a tight fit. Amazon Prime boxes make great work surfaces. :-)




With the plate securely in place, I screwed on the slide bars to each end of the insert. You don't want this fully tight yet, slide the insert on to the table first and square the rails.




Now, tighten the bolts of the new insert to the table rails. You can see that my insert deepened in color a bit after the poly coats. I also finished the piece with a coat of paste wax at the very end. What do you think?

Router Fence

On to the router fence, for which the pieces I already cut out. There are a lot of variations on this piece but what I wanted for sure was something adjustable that I could later add a feather board via T-track. The first step is to mock up the assembly and plan the slots that allow the front faces to slide. This needs to be done in conjunction with where you intend to place the supports, since your knobs that hold the front faces will come in contact with the supports. Find 2 spots on the front faces to drill holes, then with bolts inserted, plan how you want the slots to lay out and mark. Here I cut the slots already but hopefully you can see what I mean.




Once the slots are cut and support locations planned, countersink the bolt holes of the front faces so they won't interfere with any future work pieces.




Next I dealt with how to attach the custom router fence to the Bosch saw fence. Unfortunately the side slot on the Bosch fence is not a standard T track slot and I couldn't be bothered to run to the blue/orange store, so I cut two of my T track bolts down to size. Dremel + cut off wheel to the rescue.




With the head squared a bit I was able to fit into the side slot. From here you just need to decide where to punch the holes in the MDF piece that will sit adjacent. I centered my piece and marked for holes near the quarter-mid of each side. 2 bolts is good enough for this.




Due to the height of the slot in the Bosch fence in relation to the table, I really had no choice but to cut a notch to clear the adjustment knobs. I got the smallest I could find so to limit the depth of the notch I'd have to cut. A few bangs of the chisel and presto.




With slots cut and holes drilled I felt good enough for another glue up. Both of the vertical pieces sit on top of the bottom piece which will ultimately sit flat on the saw table. You can also see how I marked the holes to center the bolts from the Bosch fence to my rear piece.




While I glued on the fence face T-track carrier (upper portion of front fence face) I measured and cut supports. I wanted the triangular parts of these as flat as possible for the middle supports just in case I ever want to add a dust collection port.




With the supports cut, time for more glue, more clamps.




I let the glue harden overnight then moved on to another 50/50 poly/mineral spirits soaking. I honestly lost count of how many coats I did, I just kept soaking until my mix was gone, hitting the exposed edges especially hard.



I let this cure overnight again then did one last pure strength poly coat following a light sanding. After one last overnight curing I bolted on the front faces and screwed on the upper T-track.



Here's a look at the "knob chamber" so you can see each in relation to the slots and the supports. It's a little tight but plenty of room to move things around without collision.



There you have it! The project before the "project". Let me know what you think or if I can answer any questions. Thanks for stopping by!

Inspiration

BethePro MDF Router insert
Benchtop Router Table