Note: You can skip the intro and go to step 1 if you just want to get started building!
Trouble handling and cutting large sheets? Me too. I don't have a lot of room in my workshop for sheets let alone cutting them down. Saw horses and a straight edge are pain. Even track saws and guides take a bit to set up.
I've always wanted to build a panel saw but looking around the shop, I really didn't have the room to wall mount it. While it's nice to make a fully functional unit like the industrial units, they're over complicated and require far too much invested time. Quite frankly, I've got better things to do than spend a month of Sundays building a tool that JUST rips down sheets. I reckon most of the people who are going to read this have a table saw and really only need to get the sheets to a manageable size. I've got a table saw that can rip sheets, but again small shop and it's still quite hard and requires a lot of lifting and maneuvering. A panel saw just makes more sense from a time point of view and ease of use. I'm looking to how I'll be working 20 years from now when I'm older and probably won't be able to do what I do now.
I don't need anything complicated, just fairly accurate. And I didn't want to spend a lot of money on materials for something that just does one job. It also had to be compact. So I set out to make a panel saw, from common easily found materials, that can swing down from the ceiling, cut a full size 2400x1200mm sheet length and width ways and for under $50 (excluding tools). I also wanted to build and install it before lunch time tomorrow.
All of this can be achieved with a minimal of tools as well. At the end I'll also show some optional extra's to add on to make it even more functional.
Some Background On The Design & Features
The inspiration for this came from a multitude of other panel saw designs which I've incorporated into this design, however stripping out what I didn't need, simplifying the design to use minimal materials and some scrap I had lying around. All of the images for the inspiration came from the public domain, but I haven't include any here. You can find their original design quite easily by doing a search for DIY Panel Saws on your favorite engine or social network.
The beauty of this design is that it actually uses the factory edge of the sheets you're cutting. So you don't need to re-calibrate your jig or have enormous setup times to cut a sheet (of course if you're cutting sheets that are off square in the first place it could be problem. It's almost a cross between a panel saw and track saw with the added bonus of a cross cut saw in a compact form. It's even got sacrificial supports! The carriage is made portable and cut sheets on saw horses before you bring them in the shed without the rack if you prefer!
I found with a lot of designs they had short comings if they were too simple. Overly complicated designs just take too much money and too many parts (and a lot of time to build). Lumber carts incorporated into designs are a great idea and I had contemplated it but came down to wall space - currently I have none and I've got no where to put a lumber cart (currently). I'll be revisiting this at a later stage as I make more room in the shed.
Most rack designs use 2x4's or full sheets of either MDF or Ply - which is fine and it will do the job. For me, it seemed over kill and weight is an issue. And remembering I only have a small workshop footprint I couldn't accept anything over 2.4m wide. Simplified designs where you have a fixed carriage and push the sheet through were out. So a fixed rack with a movable carriage. The other problem for me is - No wall space. So a fixed mount to a wall is out currently. For me, a ceiling mounted rack makes sense. Being that it's a fairly old shed, I wanted the rack to be fairly light weight and compact. Most of the designs I'd seen, used a full 2.4m rack made of 2x4's or similar and the saw would cut into these. I'm not a big fan of cutting into something that you've just made, meaning you'd probably have to replace the rack at a later stage - my motto: Build it good the first time. A much better system would be to have cheap sacrificial pieces which you could replace regularly when required. They could also form part of the stabilisation of the rack and make the construction quicker, only using a few 2x4's (or similar) for the frame. I also figured that the rack really didn't have to be 2.4m wide as the sacrificial pieces could do that, cutting down the overall cost of the rack.
The Carriage and Sled
So if I went with a moving carriage, the foot print would be only slightly bigger than 2.4m - great. But when you look at designs, they're overly complicated - using specialty bearings, hinges for round pole styles or expensive T-Track. So if I was to go this route, the carriage and sled would have to be cheap and stable. I looked at a lot of ways to make a carriage and sled move with bearings, aluminium or steel channel, door rollers. The more I looked into it, the more complicated it got and the higher the price started to go. I'd used a simple fence on a table saw for years and had no problems with it, so I thought along the same lines. A couple of slots somehow made to hold a sled that could be turned 90 Deg easily. Of course you also need to stop the sled guide from warping outwards if you're only using slots - I'm thinking a larger rectangular piece of MDF or ply, couple of guides either side using the factory edge and a couple of pieces above it to stop the saw and sled from popping out. The sled will probably need a lock when it's turned sideways to cut length wise so a furniture nut & hand bolt could fill that function. The carriage could just slide along the top of the sheet, using it's own edge and maybe add another support at the bottom, just to stop the carriage from moving off 90 Deg to the sheet. I'll probably use a couple of quick release clamp to help with any horizontal cuts.
Step 1: Materials and Tools
1/2 Sheet 18mm (3/4") MDF 2400x600 (and you probably won't use it all)
1/2 Sheet 9-12mm MDF 2400x600
4 x 70x35 pine studs
Screws or nails
2 Small Gate Hinges + Screws to suit
Bottle Of Wood Glue
Couple of odd off-cuts of ply or MDF
2 sheets of A4 paper (can be recycled - not important)
4 small Toggle clamps (can buy off ebay)
Bar Of Soap or Candle Wax
Circular saw (which you could use for your panel saw as well)
Drill and screwdriver
Right Angled Set Square
Digital Calipers (could use a ruler, but not as accurate - for setting blade alignment)
Clamps are handy
Step 2: Build the Frame
Start by cutting the supports for the frame from the 70x35mm pine. Obviously you can make the rack as small or large as you want. This one is about 2m high and 1.2m wide. Basically you need two uprights (2m) and two cross rails (1.2m each). I also added another support in the middle to give some extra stability.
Notch out some rebates into the timbers to help the frame stop twisting (pines notorious for twisting). Run the saw through like in Fig1 to make quick rebates, knock out the cut-out and chisel the rest. Once you've done that, glue and screw the frame together and check that it's square by measuring the diagonals. Cut some 45 deg supports out of scrap ply, then glue and screw them to the back of frame to keep it square (fig 3 + 4).
Now use your circular saw to rip the 18mm MDF into 40mm strips as in Fig 5 (make them a little oversized for trimming later on the table saw). You can make as many as you like. I ended up ripping 5@40mm x 2.4m for sheet supports and then ripped another 4@40mm x 2.4m and then cut them in half (1.2m) for the sacrificial sheet support holders. The bottom support was 40mm+18mm (58mm) as 18mm would be the biggest sheet I would be ripping down on this panel saw. Once you've ripped everything, I used the table saw (Fig 6) to clean and trim everything to the same widths - 40mm wide as I never really trust a saw with a guide in it
The next step is to drill some mounting holes in the sacrificial support mounting pieces to screw to the frame - two holes on the ends and one in the middle. Do one piece first and then use as a guide for the rest. I also used a counter-sink bit as well - Fig 7
Before mounting these, measure from the bottom of the rack to get an even spacing for the supports. Now glue and screw the top supports in place where you've marked them (Fig 8). I also made sure that the top support is in line with the bottom of the rack so I could use the top support as a guide rail for the saw carriage if I wanted to. It pays to space the supports out and I also put a support right in the middle of the rack so I can move the sheet upwards if I'm only cross cutting a 600mm sheet. You'll notice there's more supports in the top half of the rack than the bottom.
In Fig 9, place a cross support rail on the rack supports, then glue and screw the bottom piece against it - making it nice and tight (but not too tight - you want to be able to get these out again - they're sacrificial remember)?? Clean up any glue that spills out as you don't want it interfering with your support mounts.
Once you've got all the supports in you can mount the rack to the ceiling (Fig 10 & 11) with the hinges. These are mounted to a cross piece which you attach to the ceiling. Fig 12 shows the rack with the sheet supports in place which are sacrificial and replaceable. I just used a piece of fencing wire bent to a hook and a loop attached to a screw to hold the rack in place on the ceiling. You could use two if you think the rack might bend under the weight. The rack ended up being a bit heavier than I thought!
Step 3: Build the Saw Guide
Cut some 12mm MDF (fig 13) into two strips about 40mm wide. The caddy rack I made is about 450mm wide - this will depend on what brand of circular saw you decide to use and how long the base plate is. I'm using an old Dewalt that I used for my first table saw - still going well. And much too heavy for general duties. You'll also need a square piece to fit between the rails to hold the saw in place. I just made it about 80mm wider (40mm per side) than the base caddy.
Attach one of the guide rails to the factory edge of the MDF with glue and nails (Fig 14). Wipe any excess glue off the rails as you don't want anything binding or prematurely wearing runners. Turn the caddy rack around (Fig 15), place the caddy base in-between the guide rails, then glue and nail the other guide rail in place at one end (Fig 16). Move the caddy down to the middle and end, also nailing the guide rail in place (Fig 17 & 18).
Add some soap or wax to the caddy top edges and sides to help the caddy slide easily alone the guide rails (Fig 19). Use one or two sheets of paper cut into strips and place these on the top of the guide rails (Fig 20) and then screw the guide rail covers on top (Fig 22). Check to see if the caddy moves freely but snuggly. If need be, use an extra sheet of paper underneath for spacing. until the caddy slides nicely. Fig 21 show how much clearance there is between the guide rails and the saw base.
Step 4: Saw Install & Setup
Using the base plate of the saw, square it up with the caddy base and attach using screws or screws and nuts (Fig 23). It's important to have the saw blade lined up with it's saw base. To do this, measure from the front of the blade to the outside of the base plate and again at the rear of the blade to the base plate (Fig 26+27). Using the adjustment screw on the saw (Fig 25), adjust it until the front and back measurements are the same (Fig 28). A set of electronic calipers are handy for this. Alternatively, you could just use a rule and make it as close as you can.
Once that's completed, you'll also need to set the saw blade angle of the saw so it's 90 deg to the base. Using a set square on the blade (Fig 24), adjust the saw bevel angel until the blade is at 90 deg to the base. Most saws also have a stop hex set screw for easy return angle adjustment - adjust this once your saw is at 90 deg.
Once the setup is done and the saw bolted to the base caddy, you can clamp the saw to a set of saw horses and do an initial plunge cut to the base caddy. Do it slowly with the blade spinning. If you don't remove enough material initially, the blade will rub against the timber causing the blade to heat up and most likely warp.
Step 5: Setting Up the Caddy Runner and Alignment
The runner is just a straight piece of 70x35 pine that runs along the top edge of the sheet you are cutting. It should be around 900mm. Long enough so there is an initial lead and lag for the caddy system to glide along.
First you need to make sure that the caddy is at 90 deg to the sheet being cut. Attach one end of the caddy to the caddy guide at a corner (Fig 29) and align it to the board to be cut using a long straight square (I made one that is 1200mm long) (see Fig 32), draw a line down the sheet (Fig 30). It's also a good idea to check that your square is actually square by reversing it and making sure the lines are the same.
Using a clamp at the bottom of the sheet, align the caddy with the line (Fig 30 + 32). Once you're happy, put a screw in the caddy and caddy guide to set it in place.
Once you have this done, you can remove the sheet of timber and move the caddy to the centre of the rack (remember I said that the top support rail can also double as a guide)? Now do a plunge cut into the caddy and run the saw straight down until the end of the track.
One thing I realised when I did this, was that saw dust was getting caught at the bottom of the stop. So I removed the end support and installed a dowel instead so the saw dust could fall freely (Fig 33). I also mounted a second support brace on the back of the caddy at the top to help support the caddy from splitting apart if I needed to adjust the caddy alignment.
To help with keeping the saw from moving, I installed some small clamps at the side of the caddy base. If you turn the caddy 90 deg to do horizontal cuts, there's also clamps to hold the caddy in place (Fig 36).
The last picture is the final product. The unit cuts pretty well overall.
Step 6: Final Thoughts & Modifications
There are a few limitations with this setup - namely space issues.
You have to make sure the base is not twisted when it comes down to the floor otherwise you won't be able to sit the sheet to be cut in the rack squarely.
You also can't cut a full sheet in half length ways using the top support rail as a guide (it was mainly an idea for smaller sheets). Being that they're relatively thin (18mm), they tend to sag under a weight so won't give accurate cuts on the outer edges. However you can still cut sheets down length ways using the sheets own factory edge with the guide running along it. I'd also recommend if you're doing length cuts that you clamp the end edge at the top to stop the sheet from falling onto the blade when the saw gets to the end.
The support rails on the front, while they're easily replaceable may not sit in their slots all the time. I may end up recessing a few screws into the frame to hold them in place if it becomes an issue.
The bottom support rail can be moved to the centre position to cut smaller sheets at waist height. However, I may end up making another support rail for the bottom with a 90 deg piece with some rollers on it. I'll either make these out of dowels drilled until it and PVC pipe as sleeve rollers or maybe some check plastic wheels.
I also plan to make some stops that slide on and clamp to the centre support rail for repeatable vertical cuts. I'll also add a tape measure cutting guide on the X + Y axis for easy accurate cutting.
The good thing about this unit is you can mount it to a ceiling or you could essentially mount it to a wall. When I've finished making more room in the shed and get a spare wall, this may be what ends up happening to it.
I might also end up making a video of the saw in action and explain how it works and was built.