I want to make some tablesaw inserts. None are available commercially for my General 650. What material should I use? The thickness of my insert is 7/16″. I’ve read that MDF is preferred, but it comes in 1/2″ thickness. If I use a hardwood will it expand and contract? Any advice will greatly appreciated.
George
Replies
George....
I have a similar problem with availability of "pre-made" inserts due to my using a Robland x-31 combo machine. I have made several zero clearance inserts using purple heart, oak, maple and even birch. No problems of any sort with any of them. I simply use my planer to thickness dimension the material and then use a router with a flush cutting bit to follow the contour of the original "factory insert". You can use either double sided tape or even a small brad or screw to hold the two together while routing. I have also had success in waxing the surface of the insert to prevent any drag using a good paste wax which I use on all the table surfaces of the machine.
Jon
"Knot's to you"
http://www.wood-workers.com/~jonweis
Firewood,
I just used some cabinet grade plywood. In my case it was a bit thin, so I put 1" square tabs on the bottom and sanded the tabs to achieve a flush fit.
Depends on how the factory insert is supported. Some of the after market inserts are 3/8" and have grub screws to set them level with the table top. Others are notched where needed to fit over the support tabs. My present saw (dewalt 746k) uses 1/2" thick inserts and corian off cuts are just right. But make your own is the cost effective way. I made 4 inserts in 45 mins, yours might take alittle longer 'cause of the thickness. They are priced at $20+ in the stores!
I have a General 350 and make all my own inserts out of 1/2 " baltic birch .I belt sand the bottom and counterbore for 3/8" No 6 sheet metal screws that I back out to level the insert
MDF will change with humidity -- if I go more than a week without heating up my shop (here in Rain Forest country, WA) the one MDF insert I have will get stuck. Have to blast it with a hair dryer to get it out without breaking it.
On the other hand, the two inserts I made out of scrap maple never seem to swell enough to cause problems. I use the plane-it-down, cut-it-with-a-pattern-bit method too, works great. The fun part with a Jet contractor's saw is the fact that the blade doesn't drop below the lower surface of the table.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Forest Girl,
I designed/built this TS insert sled for a friend of mine that has a Jet Contractor saw like yours. He wanted a safe way to kerf and cut shop built inserts without having to change over to a dado blade.
The sled allows the user to drop an unthicknessed, unshaped insert blank (rectangle) into the cut-out, clamp it down with the simple hardwood hold-downs, and either run the unit over the blade or clamp the sled to the tabletop and raise the blade into it. Remove the insert, and thickness/shape as usual.
The sled was also modified to hold three inserts for a mini production run. The blade could be tilted to common angles to make zero-clearance inserts without the sled ever leaving the tabletop. Fast, quick, and safe.
If you like the design, feel free to pass it along.
Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.
Edited 3/19/2003 11:45:45 PM ET by Jackie Chan
Edited 3/19/2003 11:46:29 PM ET by Jackie Chan
Dan, thanks very much for taking the time to post your sled diagram. Anything that makes this process safer is a winner in my book! I've copied and edited your attachment into a 24KB jpg file, and attached it below. If you'd like, you could right-click/save as to your computer.
Thanks again! [NOTE: the attachment below is from "Jackie Chan" of #14 above]
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 3/20/2003 11:36:07 AM ET by forestgirl
Edited 3/20/2003 5:55:15 PM ET by forestgirl
FG
Thanks for the terrific drawing - you're the kind of 110% person I'd love to have on my team!
What software do you use to prepare your drawings?
Paul
WHOA, WHOA, WHOA, WHOA!!! That's Dan Kornfeld's (aka, Jackie Chan) drawing. See http://forums.taunton.com/tp-knots/messages?msg=11293.14 #14 above.
I'll go back and edit that post (again) to make it clear. PS: Glad to be on your team, but don't count on me to draw anything, CAD or otherwise. I'm clueless.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I'm not exactly recommending this, but one time when in a pinch, I had to thickness plane some MDF to make an insert. The finish quality was good, but I can't vouch for the durability of the planer blades over the long haul if this were a regular practice.
As for making the initial cut into the insert, commercial insert manufacturers make it easy by starting the kerf for you on the under side so the insert can seat properly with a 10" blade. For us do-it-yourselfers, I find a good way is to use a single outside blade from a stacked dado set. The smaller blade (whether it be 6" or 8") can be fully retracted underneath the table. Circular saw blades (7-1/4" and the like) will also do the trick as long as the arbor and kerf matches the regular table saw blade. And don't forget to use a push stick to hold down the insert as you raise the blade for that initial cut (but keep the stick clear of where the blade will appear).
Yep, the dado-blade approach works for 90-degree inserts. What's tough is making the 45-degree ZC's. Even the pre-grooved retail inserts don't help with that problem.
BTW: Isn't moving the fence over the insert safer than using a push stick? That's the method I've seen the most and used.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I had 1/2 sheet of 1/2" ABS plastic so I use that using the original for a pattern bit and use the fence to hold it down. The biggest problem I've had with them was right after I made the first one I cranked the bevel angle over and bent a really nice blade. Dooh!John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
I use 1/2" birch plywood. After it is sized to the opening, I drill four 1/8" holes in the insert that corresponds to the support tabs of the saw. I then insert four set screws in the holes so I can level the insert from the top. It works for me.
I wonder why contractor saws don't completely lower below the insert. Does anyone know?Dan T.
"I wonder why contractor saws don't completely lower below the insert. Does anyone know?" -------------- To make us want a cabinet saw? Who knows, one of those dumb things.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Cabinet saws (at least my Jet ...) don't retract enough either. To get a zero clearance insert I have to make it and use a smaller diameter blade to cut the kerf.
I think it's an engineering thing. Why make a saw so that the blade can travel another inch or so away from the insert, just so you can make a cut in a zero clearnance insert? It would probably cause more tune-up problems in normal use ... longer travel equals more potential play, etc.
John
They tantalize us though! The Jet blade only needs to go about another 3/8" or so, it seems. Darn!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Oh Ow!!!!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Wouldn't the smaller diameter blade work also for a 45-degree insert? Forgive me if I am not visualizing what you mean correctly for it's a little late in the evening for me. The fence instead of push stick is a great idea. I assume your method is to place the fence over the insert to the left of the blade. Unfortunately, I have the Unifence which makes the right side of the fence kind of inconvenient for that task (I could flip the fence to put it on the other side of the carriage, but I'm lazy enough as it is).
Ricky, I thought the dado blade method would work for 45* also, but it didn't. The insert I made that way looks like . . . well, it looks bad. I guess it's because, at that angle, the 8" blade enters the bottom of the plate in a different place than a 10" blade would. Doesn't matter how much sleep I've had, I couldn't explain it from a geometric POV.
Of course, I'd be glad to be proved wrong in this particular case.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Is moving the fence over the insert blank really a safe way to clamp it in place? The instructions that came with my new Grizzly cabinet saw says to remove the fence completely, then use two pieces of lumber (like 2x4's) over the ends of the insert and then clamped to the table.
I just made my very first ZC insert this way last night, and it worked really well.
I also learned that the dust collector is really pretty useless when creating a ZC insert. :-)
-M.
Mark,
I made several ZC inserts on the Griz using the fense method. Maybe if i read the instructions I would have tried the 2x4 method...
Mark, the fence-clamping method is the one illustrated in most books. It's pretty darn safe, as long as the fence isn't over the sawblade! In that case, the fence is left much the worse for wear. I have trouble getting much clamping action on my saw without a whole lot of spacers being added. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I use Mahogany cause I have lots of scraps. I plane the pieces to thickness, then cut them out on the bandsaw. I then put the insert in place and then raise the blade up into the blank to cut the slot. I then mark lines and cut a slot on the back of the insert for an Oak splitter. I keep several inserts for use with different blades. I put splitters on those for the ripping blades.
However, for the last couple of years I have been using my bandsaw much more then the table saw. That is due to my current line of work.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
I'm not real familiar with shop-made splitters. Do you make the splitter the same thickness as the blade? I assume it would be in direct line with the blade, right? How high does it stick up from the insert? Is it glued in or just a tight fit? I'm sure this has probably been covered before but I'm too lazy to search.
TCK - I make mine so that they stick above the insert about 1" and make them about 1" wide. Don't make it thicker than the blade, obviously. Since I cut with the fence to the right of the blade, I make sure the right side of the insert is lined up with the right side of the blade. I make them a medium tight fit and just wedge them in. To tight and you run the risk of splitting the insert. Wedging them in allows me to remove them when the need arises.
Using a splitter, as well as helping to prevent kickback, will give you more precise and cleaner cuts.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Whatever material you decide on install a splitter! Make it a wide as your blade, NOT as wide as the slot. (sometimes the slot is a couple hundredths of an inch wider.) Ease the edges of the splitter.
I've used 6-8mm cast acrylic, others I know prefer lexan since it's stronger. But if your saw has a drop-in type, most any kind of flat wood should be okay. Mill it with a router if necessary to get it the right height.
View Image
Green Gables: A Contemplative Companion to Fujino Township
This forum post is now archived. Commenting has been disabled