MFT'ing my Sawstop

[stoli]

Given the thread the other day about trying to re-envigorate the forum, I decided to post this here, even though it is about the replacement of my BT3K.

Motivation

I recently replaced my pimped out Ryobi BT3K with a Sawstop PCS. My BT3K setup had 2 sets of rails with an extended table to the right of the blade. The extension table included a woodpecker PRL router plate.

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However, there were 2 aspects of my extension table that I did not like.

• there was no way to clamp or fix workpieces to the top,
• the top was built into the cabinet and was not replaceable (and I had mistakenly cut into it multiple times)

The Sawstop PCS shipped with a simple flat extension table. The motivation for this project was to regain the router plate while correcting the 2 issues above.

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Full Goals

• Create router table
• Clamping/fixturing options
• No new holes in sawstop hardware
• Modular/replaceable top
• Flatter than sawstop table
• Minimize cost
• Allow for future expansion (dust box and router bit storage)

[stoli]

Creating the top

The original sawstop table seemed like a good size, so I cut a piece of 3/4 MDF to 27x40. It was straightforward to create the recess for the router plate. I just had to remember that I will be adding laminate later, so the depth of the recess needs to be adjusted.

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For extra clamping, I decided to duplicate the festool mft table idea of having a grid of 20mm holes. For my purposes, a rough grid of holes would suffice to give clamping options.

I do not need to have a perfectly spaced set of orthogonal holes, but I still gave it a try. I do not have an LR-32 system, or even a holey rail, so I had to make do with my OF1400, the 20mm router bit, and flat clamps. I will be referencing all holes from the front side.

I broke the problem down into three parts: get the clamp square to the front side, set the router at repeatable distances from the front edge along the clamp, and relocating the clamp along the front edge at repeatable spacings

Clamp square to front edge

It was pretty straightforward to get the clamp square to the front edge using a woodpecker triangle.
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Repeatable router placement along clamp

This was the most complicated part of getting a good grid. I started by creating a simple jig that slides along the clamp and butts against the edge of the MDF.
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I made use of the guide stop attachment to squeeze the router solidly against the clamp. This ensures that the router moves perpendicular to the front edge along the clamp, and by butting the router against the jig, it gives a repeatable start position.
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I then cut a series of MDF spacers to get repeatable spacings along the clamp. Doing this I should be getting fairly repeatable placements, but the exact distances between the holes is only as good as the exact lengths of the spacers
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Relocating the clamp

Relocating the clamp was fairly easy because I actually have 2 clamps that can be used. So I simply created a spacer to move the front edge by 96mm each time it was used. I only used the spacer for spacing - the clamp was squared each time. Additionally, the jig was reset to the front edge each time since it had to be relocated to the other clamp. After the clamp was repositioned, a series of holes was created down the clamp. Move the clamp to the next position, repeat.
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[stoli]

Attaching the rails

I tried making a grid structure for under the table, but wasn't satisfied with the resulting flatness and stiffness using MDF, and any grid structure would interfere with clamps coming through the holes. I purchased some 1.25" aluminum angle from a big box store, and was about to start cutting it when I saw a post about 8020. I had actually just purchased some 10 series for fences for soon to be made sleds, and discovered that the 15 series is nearly the perfect size, and would actually be cheaper than the simple aluminum angle (there was a set of 4 38" 1515 for auction that I won).

If I attached the 1515 using the 8mm holes already drilled in the rails, the table ended up slightly too high. It turns out that the location is mainly set by the bolt width in the slot, so I decided to widen the slot at the three bolt location. Again using my OF1400, the edge guide, and a home made edge guide, I was able to guide the router parallel to the length of the extrusion, for just enough for the bolt to clear.

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The 1515 rails attach to the sawstop rails using 8mmx16 flat head cap screws and 8mm tnuts.

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The top attaches to the 1515 with 8mmx25 flat head cap screws into 8mm tnuts (they have not yet been drilled in the pic below)
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Attaching the legs

The legs originally attached to the sawstop rails. For various reasons, I choose to attach a third piece of 1515 to the outside edge of the table. The legs attach with a right angle bracket using an 8mmx12 hex head bolt into an 8mm tnut and an 8mmx25 bolt. No new holes needed to be drilled into the legs. Not the most stable, but my original idea of mounting into both open tslots didn't work out because there was not enough extension of the adjustable feet in the supplied legs.
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Attaching the supplied adjustment device to the table

At the inside of the table, I dominoed a 1.5" piece of MDF and installed 2 6mm tnuts. The included adjustment device attached as before.
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[stoli]

Evaluation of design against goals

• Create router table: success, router plate mounts fine. I had a combo t-track/miter slot before, but never used the miter slot, so I just used a simple t-track.
• Clamping/fixture options: success. I now have a grid of 20mm holes. I have already used them to help complete this project. Currently I only have a set of woodpecker delrin pegs, but the table clamps will work if I decide to purchase. I have checked the orthogonality of the grid. Most of the pattern is spot on and I get no rocking. However, there are some that give up to a 0.010" gap over 24". But that does not diminish the utility for me - a perfect grid was just a stretch goal.
  
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• No new holes in sawstop hardware: success. Used the 6 holes in the rails that were used for the original table. Used the 4 holes in the legs that were used in the original table.
• Modular/replaceable top: success. top is attached to 8020 and completely replaceable.
• Flatter than sawstop table: partial success. The sawstop table had dip of 0.043", my table has dip of 0.005". The only concern is that the table is one piece of MDF thick and may sag with the weight of the router lift. The third piece of 8020 was attached to the end of the table to mitigate this concern. I score this as a partial success since somehow my t-track is 0.020" too high towards the end of the table. I know I checked that the slot was deep enough the whole length of the channel. I must have screwed up when epoxying it in place. I plan to take a router and flush the track at some point.
• Minimize cost: success. I used scrap MDF and laminate. The 8020 was cheaper than equivalent aluminum angle. T-track was already purchased. The only cost was in the mounting bolts.
• Allow for future expansion (dust box and router bit storage): success. There are 2 open channels in each of 3 pieces of 8020 that can be used to attach whatever I need in the future. I have already attached the router power switch and will be hooking up the main saw power box soon.

Now it is time to make some deliverable projects!

[bigstick509]

Very ingenious way to do the 20mm holes. As good or better then AskWoodMan method over on You Tube.

[stoli]

I just looked at his method. He uses a fence so he gets perfect alignment in one dimension, but has to eyeball the other dimension. That is why I liked using the stop blocks.

I also think I know why I had some issues. When I got to the last setup of the clamp, there was not a lot of bearing surface left on the left side of the board to square against. I could have used the other side, but that would have removed the spacing reference from the other clamp. The real solution would have been to route the holes on an oversized top, then trimmed the top to size. This would have allowed me to locate the grid exactly where I wanted, and been able to square off the last clamp.

Btw, AskWoodman was where I got the idea for my first 8020 order - Ill be using it for fences on the news sleds I need to make for the saw.

[Bruce Cohen]

Great looking tools, can I have them when you're finished with them??

[stoli]

Sure. I expect to be using them for the next 25 years or so...

[cray-]

Yanks using the metric system, how bizarre!

Jokes aside, very nice setup and a well conceived system for getting the job done.

One last thing: I thought 3/4" was the default size for this sort of thing and that converts to almost 19mm, not 20mm, no?

[stoli]

I am a scientist by profession, and use the metric system daily, but only recently have I started using it in woodworking. I still think in imperial during design, but for in process measurements, using mm can't be beat, which is the whole point.

I've been slowly drifting towards the Festool system, which I believe is based in Germany, hence the metric measurements. The title comes from Festool's "Multi Function Table" (MFT), which uses a series of 20mm holes on a 96mm grid. When combined with their track saw, that system can rival a good table saw in many ways. I have seen many people making use of the orthogonality of the holes to align the track, but have only seen one add-on that requires precise 96mm spacing.

[tfischer]

Cool project - thanks for sharing!

I recently discovered the "woodgears.ca" site and videos, and he does most of his work in the metric system. That wasn't something I had even considered before seeing that.

[stoli]

Mattias is from Canada, where the metric system is common.

Once I got over the truly small hurdle, I can't imagine ever trying to figure out where the center of a board is, or how to space multiple object across a width, using imperial. Metric really is straightforward. I don't know how many times I had screwed up before trying to subtract 4 13/32 from 6 19/64. But it is pretty easy to do 159.9-111.9=48.0. I got a fast cap tape measure that has both imperial and metric on it, that has helped too. Just make sure you know not to switch back and forth within a measurement "series"; that is as bad as using 2 tape measures for a project.

[tfischer]

Mattias is from Canada, where the metric system is common.

Yeah more common than in the US, but it sounds like most his tools (drill bits, etc) dimensional lumber, etc is actually in imperial units. He has an article about how he prefers working in metric for the precision.

None of my woodworking measuring tools (other than the digital calipers) even have an option to be metric, so I'd have to start over buying all that stuff. I have to admit that thinking in fractions just doesn't cut it very well when woodworking - if we were all trained on the metric system from the start nobody would even consider using imperial units. Years back I made up a spreadsheet of frac units by the 64th and their decimal equivalent... I have it taped on my shop wall and refer to it frequently.

I just searched the HD site and they only have one metric tape measure and it's $23. I wouldn't like a combo one at all as you'd always have to make sure you were on the correct side of the tape. The tape I normally use even has numbers on the bottom side which I use sometimes.

[cray-]

Metric/Imperial combo rules and measures are pretty common down here in Aus and I'd assume most Commonwealth nations. Might have more luck over the border to you north if you want to buy something.

Festool being European, the 20mm makes more sense. I think I got thrown by the fact that most Americans on YouTube and forums use 3/4" for dog holes and MFT clones.

[dbhost]

Great addition! Looks very functional.

Curious though.

Why 20mm holes instead of the standard 3/4" holes? I would think 20mm would make things like holdfasts harder to find.

Why MDF? I would be worried about it being too prone to sagging with any sort of weight, and swelling with changes in humidity.

Thanks for sharing, you are giving me some great ideas for my table saw workstation build!