I’m in the process of making a panel saw to rip sheet materials. I’m not working with a kit, but assembling it myself. A 7-1/4″ skill saw will ride on the vertical axis (track) to make cuts of 4′ or less. For longer rips, like the length of an 8′ sheet, I plan to rotate the saw 90 degrees, set the “height” of the cut, and feed the sheet through the saw. My question: Will there be a problem with the material binding on the blade as the cut progresses? If so, how does a typical panel saw overcome this? Does it need a “splitter” mounted behind the blade?
Edited 4/24/2005 4:52 pm ET by saul
Replies
Yes, if you look at a SSC saw it has a nice study splitter mounted to the saw plate that does exactly what you describe, but was more like a riving knife.
"splitter" mounted behind the blade?
In front?? Sorry.. YES you need a splitter of some type. Horizontal cutting on a 3/4 inch hunk of ply can put quite a load on the splitter..
I have a home made panel saw I made long ago from black iron pipe!
Not the best way BUT... I just use a hunk of 'H' profile aluminum (Thickness of saw blade). I just cut until I can safely slip the 'H' into the cut and continue.. Yes you have to be sure that the 'H' does not hit anything as the sheet is pushed through.
By the way.. The sheet rides on rollers I put in at the base. The rollers are adjustable so you have a perfect horizontal plane to ride on.
Will, I might bug you a bit about this, because I'm determined to make this panel cutter from "scratch", and you've been down this road before. I'm still designing, but right now I'm planning to mount a "tray" onto sleeve bearings which will ride on two 1" aluminum tubes. For the saw, I'm dedicating a 7 1/4" skilsaw (not wormdrive) to the project. I may use extruded alum. for the basic frame, with some melamine runners mounted horizontally to help support the sheets. For long rips and possible router option, I thought I might mount the saw on a square base which could be removed and turned 90 degrees. A counterweight/pulley system will keep the saw balanced. What I still don't have worked out is: 1.a brake to hold the saw firmly at one height. This is mainly for ripping horiz., but it would be nice if I could figure out a way to have it grab automatically whenever the saw was let go. This would be tricky, though, if the saw is to remain removable. 2. The afore mentioned "splitter" - I just realized that a wedge mounted to the saw itself might just get bound as well. I like your solution, though. What happens at the very end , as the sheet finally comes in two? do you have to follow the blade with shims?
sorry to ask so many questions, but I'm a big believer in exploiting other people's hard work :^) thanks
p.s. oh yeah, what exactly did you use for rollers?
be nice if I could figure out a way to have it grab automatically whenever the saw was let go..
I would have to think on that 'a-bit'. I used roller-chain for the counter balance and had a split nylon block (around one of the vertical carriage rails) with a big thumb screw to clamp the carriage in place. Nothing fancy here.
1" aluminum tubes...
Unless you can source some extruded stuff with ridged inner walls I would think the aluminum would flex to much. Maybe not, but stainless steel may be better but much more expensive.
melamine runners...
Those sheets would probably be hard to push on that. Possible, but I would think sort of unsafe if you are forcing yourself pushing the material while cutting. I made up a bunch of rollers (from cheap 1 inch steel rod I found at a scrap yard that was cut on a lathe for ball bearings). All those ball bearing got sort of expensive. Not to mention cutting and fitting all the adjustable bearing mounts. Never again!
If I had to do it over I think I would make some sort of trolley riding in a heavy 'U' channel using some skate board or roller blade wheels. I would recommend making the trolly as long as possible to support the sheet as much as possible. Also, the base should be adjustable so it can be leveled.
What happens at the very end , as the sheet finally comes in two?...
I just had a steel pin that stuck out just in front of the blade (splitter?). This keeps the curf open near the blade and the 'H' block kept the curf open and kept the two cuts from 'wandering' side to side as the cut gets longer. Sort of a pain sticking in the 'H' block but simple and worked for me.
The pin itself would work OK as a splitter but I also found that I needed something to keep the cuts in line while cutting. I also had a adjustable bar with swivel casters to support the back of the sheet but the cuts would sometimes want to go different directions so I used the 'H' to hold them in 'sort' of alignment.
I did not use a router in mine but that is a GOOD idea.
I would send pictures but I no longer have the panel cutter. I gave it away. I now have a home made 'out-feed' table for my saw with embedded rollers and works OK. When I had the panel cutter I did not have room for a good sized out-feed table.
Some suggestions....
Make everything adjustable! Well, unless you are sure it will NOT move.
Be sure to make the carriage to frame AND carriage to the sheet supporting base adjustable so you can make small adjustments for 45 degree if something moves. Also the carriage tubes to the frame.
Tip the panel saw assembly from vertical as far as possible for the room you have for it. I think it helped keeping the sheets in control and less weight on the splitter pin.
I would think you would be MUCH happier with the sheet riding on some sort of roller assembly.
I used black iron pipe because I had a lot of 1 inch at the time and had access to a arc welder and metal working tools.
If you have access to a scrap metal place that will let you 'look around' you can save ALOT of money. Not precision... but a long hunk of string stretched along a hunk of metal will tell you if the metal is bent. OR take a 8 foot long machinists straight edge with you.. LOL
You will need something like a spring loaded roller to hold the sheet to the base of the saw carriage so the blade cuts at the angle you set the blade to. On a table saw you have the weight of the wood on the table but with a panel saw you need some way to keep a sheet of (various thicknesses) in FIRM contact to the bottom of your carriage.
I had a lot of fun making it and I may make another when I get around to it..
Have FUN with yours!
Hey Will,
good stuff. this is just what I was hoping for. If you don't mind, sir, a couple more questions:
-You mentioned a split nylon block for the brake - this is what I figured I'd do. Were all of your bearings made of that stuff? I'm assuming you had four, and I would think they should be good sized chunks, through bolted to the tray. When you say, "nylon", do you mean that softish, almost "greasy" stuff that spirals when drilled, like they make toothbrushes out of? what's a good source?
-the 1" aluminum at the hardware IS light, you're right, but its also non-corrosive, fairly inexpensive, and actually pretty stiff.. I wonder, though, about it supporting a pinch roller, like you mentioned-would this ride with the "trolly" (and saw) to clamp down the material as it passed under the cut? I guess during a 45 degree horizontal rip the blade would tend to "dip" in and out of a less than flat sheet, correct? That is a problem - what about a long roller, like those found on the back of lawnmowers? I'm having trouble picturing a spring holding unruly plywood flat, unless it was huge.
>"...had a steel pin that stuck out just in front of the blade (splitter?). This keeps the curf open near the blade and the 'H' block kept the curf open..."
-the splitter pin. You mentioned it "in front " of the blade, but you mean that it follows the cut, right? I'm thinking that a good sized (bigger than kerf) H-wedge in the start of the sheet could keep the pinch off the blade for most of the cut, and the splitter could help a little at the very end.
I'm sorry to make you walk through all this again, but I do appreciate the help.
"in front ".. I went 'brain dead' SORRY 'IN BACK' like you said originally...
Were all of your bearings made of that stuff.. No.. Just the clamp part.
I used small ball bearings with adjustable eccentrics that captured the circumference of the pipes. A three point contact configuration to the pipe. Make sense? 12 ball bearings as I remember. A set of three at each corner of the carriage. Probably over-kill.
By the way. I put the pipe for the carriage rails in a LARGE metal lathe (lunch time at the place I worked at the time) and 'trued-up' the circumference. As I remember the pipes were very true 'as is' and only had to sort of cut off a few high spots. I could have just sanded the pipe and saved all the lathe setup time.
that softish, almost "greasy" stuff .. Brillcream? LOL..
I called it nylon.. I'm not sure what it was but lets just call it plastic.. The 'clamp' just secured the carriage assembly to one rail to keep it in place when cutting.
I would think using plastic/hardwood blocks could be used for 'bearings' for the carriage but just not my ideal. I have used a low cost after market sliding table for a table saw with 'plastic' carriage bearing and for me it was FAR from ideal. But then again, for a panel saw, you are only moving the carriage not a 4X8 or larger sheet of wood.
Go ahead and use the aluminum tubing and bearings you had in mind.. If you find that the aluminum is not stiff enough you can always 'up-date' to a different material.
about it supporting a pinch roller.....
As far as holding the wood to the carriage while cutting you could do it in many ways.
I just had a four ball rollers that were mounted so the ball was just proud of the bottom of the carriage. I do not remember what the trade name is but the bearings are a large metal ball held in a cup. At the back of the sheet I had a spring loaded ball roller (on a heavy spring loaded hinged arm) that 'pushed' the sheet toward the rollers on the carriage. NOTE.. This sort of arrangement was also at the bottom of the sheet.
Yes, there is was 'resistance' from the rollers to overcome as I pushed the sheet into the rollers. LOL.. ALOT of resistance with a 3/4 inch sheet.. Well, at least I knew the sheet was held where I wanted it.
I finally got around my design problem by making the spring loaded roller at the back of the sheet into a assembly with several rollers that sort of made a 'ramp' of rollers that the sheet road up on.
Any way you do this is OK as long as you have the sheet held firmly (at cutting point) AND the sheet is at 90 degrees to the saw blade while cutting. Remember, if the sheet is in any way tipped from vertical it will not be a true 90 degree cut.
If I remember correctly, the panel saw at my local Big Box just has some 'V' channels that the sheet lays on and there is a large gap from the surface of the wood to the bottom of the carriage. They throw the wood in and cut! DANG! The sheet is at ANY angle to the blade and you get charged for it! I have in the past sort of mentioned the sloppy work to the guy doing the cut and he looked at me like "I" was the idiot!
Go to your local Big Box and look at the panel saw they have.. You can at least look at the problems you could run into making yours.
I am not sure that pushing the sheet toward the carriage was the best way to do it. It worked for me but I guess I just did not like any gap between the carriage and the wood. Probably more than you want but I also did this to help in avoiding chip-out at the cut. The carriage plate had a replaceable 'zero-clearance' throat plate and the pressure roller assembly at the top also had a replaceable face plate. With a circular saw you would want the 'bad' face of the sheet toward the carriage. If I did it over I would make a pressure plate from Ultra High Molecular Weight material that pressed against the 'GOOD' side of the sheet and use it to hold the sheet to the carriage AND for a zero clearance 'anti-chip' area.
I'm sure if you just have the sheet held to the frame and have a gap it would be just as good as long as the sheet is always in the same plane.
what about a long roller, like those found on the back of lawnmowers..
I used the ball rollers in cups so the sheet or carriage can be moved/held in any direction. With a long roller it would have to me rotated for vertical and horizontal cuts. Which could be done for horizontal or vertical cuts. Just a little more set-up time.
unruly plywood ...
Most of the ply I cut was cabinet grade so did not do to many 'funny' things when cut.. Sometimes it did but not very often. My main concern was marking the panel when cutting.
I never did it but since it is your money and time you may want to think about making the carriage/rail assembly so it can pivot for angle cuts. I do not think it would be that hard to do. Just longer carriage rails to allow for the Maximum angle you would want and the pivot mounts. Depending on how many angle cuts you do could save a trip to the table saw.
Are you looking at the Safety Speed Cut saw and Saw Trax for ideas as they have a lot of time in the engineering of such saws. Heavy electrical conduit is a lot sturdier and cheaper than aluminum tube.
Thanks, will check out your suggestions. I have decided against aluminum tube, too.
Hi Saul,
Just wondering if you have completed the saw and if so, how did it turn out? Any pictures, ideas for improvements, things you would do different next time? I've thought about building one myself - they seem so useful when building projects from sheet goods.
Thanks,
Dave
Dave,
Sorry to dissapoint, but I had to put that project on the back burner. In the interim, I made a "shooting board" out of a strip of hardboard. A thin aluminum straighgtedge runs down the middle, and I ripped one side with my skilsaw at 90 degrees, the opposite side at 45. This way I have a straightedge which shows exactly where both cuts will be made on the workpiece.
I'm still interested in making a panelsaw, though, for a bigger project coming up. I hope you will make some advances and post your results. good luck and happy new year!
Saul
Although I don't look forward to ripping full sheets, they go straight to the TS; it's the initial crosscuts that are a bear.
Several years ago, Woodsmith had plans for a pair of "A" frames that accepted a full sheet, vertically.
When I had a commission that required 8 sts. of Melamine, I made that set-up.
It works with a Skillsaw and handles "panel whacking" across the 49 way handily.
I can look-up that article, if anyone has interest in it.Arlington, Texas (The dash in Dallas-Fort Worth)
Practice...'till you can do it right the first time.
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