# Cutting splines on a table saw



## 716 (Nov 22, 2015)

I want to edge glue up 7" long hard maple boards. For that I plan to cut slots along the whole length of the boards and insert splines. I plan to use a single end blade from my 8" dado stack, as my thin kerf blades are too thin for this task.
In order for the spline to not show up I plan to slowly lower the board on the blade from above, about 5" from the end and stop the saw when the cut is 5" from the other end. As the boards are not perfectly straight I will use two featherboards before and after the blade.
Do you see safety problems with this setup ?


----------



## joek30296 (Jul 21, 2010)

I assume you're talking about 7 ft. boards and not 7 inch since you're leaving 5 inches at each end. I've done that a number of times successfully. The only problem I see with using one side of your dado blade is many sets have left and right blades and teeth point either left or right. You might be able to use your thin kerf blade by making the first cut, then turn the stock end for end and cut again. Set up on a practice piece first to get the right width slot.


----------



## 716 (Nov 22, 2015)

So what can happen when cutting with the only lets say right teeth ? Will it try to pull the board to the side ?
I am not sure that two pass method will give me acceptable slot consistency especially if the boards are of slight different thickness.


----------



## shampeon (Jun 3, 2012)

Why are you adding splines? A glue joint will be stronger than the wood. If you're concerned about alignment, use some cauls and clamps.

You're really going to need to dimension the boards correctly before glue up.

And let's just put me down as "concerned" about the idea of slowly lowering a thin board onto a spinning saw blade by hand.


----------



## shampeon (Jun 3, 2012)

Also, please don't put a feather board on the outfeed side of a blade. You're really flirting with dangerous kickback.


----------



## 716 (Nov 22, 2015)

> Also, please don t put a feather board on the outfeed side of a blade. You re really flirting with dangerous kickback.
> 
> - shampeon


Why ? The cut is not through so it is not going to pinch the blade.


----------



## 716 (Nov 22, 2015)

> Why are you adding splines? A glue joint will be stronger than the wood. If you re concerned about alignment, use some cauls and clamps.
> 
> You re really going to need to dimension the boards correctly before glue up.
> 
> ...


It is a lot of clamps that I do not have, the same goes to thicknesser. 
Do you think lowering the blade below the table surface and then rising it when the board is set up would be a better approach than lowering the stock onto the blade ?


----------



## shampeon (Jun 3, 2012)

Putting pressure on the board before and after the blade will push the board against the side of the blade while it's spinning, causing kickback.

But it's your nuts, man.


----------



## shampeon (Jun 3, 2012)

If you're going to do woodworking, you're going to need clamps and a way of dimensioning your stock. Cheap f-style bar clamps will work fine for this. A hand plane and some 2×4s will get you some cauls.

I do not recommend raising your blade into your boards, and really don't think cutting slots for splines is a real solution. This whole operation just sounds dangerous and unnecessary. Get the boards prepped first before even considering gluing them up.


----------



## bondogaposis (Dec 18, 2011)

Why ? The cut is not through so it is not going to pinch the blade.

Yes, it could very well push on that thinner wood into the blade after the cut. It depends partly on how deep the cut is, the deeper it is the more likely that the feather board might cause the blade to catch. You could still use the feather board but put no tension on the rear one. I personally would prefer to cut stopped splines on a router table w/ a slot cutter.


----------



## 716 (Nov 22, 2015)

> Putting pressure on the board before and after the blade will push the board against the side of the blade while it s spinning, causing kickback.
> 
> - shampeon


There is the fence the board is pushed into not the blade. No ?


----------



## 000 (Dec 9, 2015)

I would do it all day long as long as you have the experience. I wouldn't use 2 feather boards. If it were me I would use 1 long board.


----------



## Ger21 (Oct 29, 2009)

After passing the first featherboard, the release of pressure can cause the board to move a little bit into the blade, possibly causing kickback.


----------



## 716 (Nov 22, 2015)

> After passing the first featherboard, the release of pressure can cause the board to move a little bit into the blade, possibly causing kickback.
> 
> - Ger21


Huh ? Are you saying that featherboards are inherently dangerous and should not be used ?


----------



## hotbyte (Apr 3, 2010)

This….you can buy 3/4" pipe clamps and some 3/4" black pipe fairly cheap.



> *If you re going to do woodworking, you re going to need clamps* and a way of dimensioning your stock. Cheap f-style bar clamps will work fine for this. A hand plane and some 2×4s will get you some cauls.
> 
> I do not recommend raising your blade into your boards, and really don t think cutting slots for splines is a real solution. This whole operation just sounds dangerous and unnecessary. Get the boards prepped first before even considering gluing them up.
> 
> - shampeon


----------



## GregD (Oct 24, 2009)

This cut could also be made using a router with a wing cutter.

But it is completely unnecessary to use splines for a panel glue-up like this. When I was new to woodworking I would do something similar, but it was a lot of work and if anything made the glue-up more difficult. While one might think the spline will perfectly align the boards, it often doesn't. And it certainly does not reduce the need for clamps - if anything you may need even more pressure to close the joint tight.

Like most things in woodworking, glue-up requires appropriate tools and skills. Your results will get much better after you've done it a few times. The first attempt or two are likely to be very stressful and disappointing. Consider cutting a few strips of scrap plywood and practice gluing them up. It will be very educational - well worth the time and cost of the wood.


----------



## OggieOglethorpe (Aug 15, 2012)

If I didn't have a router and wing cutter, I'd skip the dado end and use a rip blade.

Plunge and stopped cuts are safe on a table saw if you're using a stop block at the ends of the cut. For a plunge, the infeed end of the board needs to be against the stop as you lower the far end onto the blade. For a stop, the outfeed end needs to be against a stop as you lift off the blade.


----------



## GregD (Oct 24, 2009)

> Huh ? Are you saying that featherboards are inherently dangerous and should not be used ?
> 
> - 716


No. But you do need to avoid situations where the wood will be pushed sideways into the blade.

Consider using your proposed featherboard arrangement for a rip cut. The featherboard on the far side of the blade will squeeze the offcut into the back side of the blade - kickback will almost certainly occur.

It is not as bad in your proposed operation because you are cutting a groove and not making a through-cut. There is still a chance that a very tight featherboard would tend to close up the groove, squeezing the back side of the blade in the wood. It would be better to raise the featherboard up off the table so it is entirely above the top of the groove (kerf). Then it is pushing against solid wood all the way through to the fence, and there is no stress trying to close up the kerf.


----------



## 716 (Nov 22, 2015)

> I would do it all day long as long as you have the experience. I wouldn t use 2 feather boards. If it were me I would use 1 long board.
> 
> - jbay


Which 1 long board ? You mean like a secondary fence on the left of the cut ?


----------



## 716 (Nov 22, 2015)

> Huh ? Are you saying that featherboards are inherently dangerous and should not be used ?
> 
> - 716
> 
> ...


Thaks guys for all your help, but I feel that sometimes you just say No no matter what. I do not think there a featherboard in the world strong enough that would close a shallow grove needed for a spline (probably 1/4" to 3/8") in hard maple ( see OP ). Even if there was such featherboard it would be impossible to push anything through it.


----------



## ShaneA (Apr 15, 2011)

Uhmm, they have a tool for this, a biscuit cutter. However, no slots are needed. As Ian pointed out, the glue is plenty strong. Jointing the boards properly before glue up is the key here.


----------



## HokieKen (Apr 14, 2015)

Sorry 716, but I'm gonna have to agree with those above… you should never use a featherboard after the leading edge of the blade. Even ignoring, the fact that wood relieves internal stress after it's cut, unless your fence is DEAD parallel to the the blade, you will be pushing the board into the side of the blade. And your fence should be toed out .010-.030" to avoid any chance of pinching.

That being said, I see no problem with what you want to do using a single featherboard. However, I think you'd save a lot of work by using biscuits or just gluing up. The problem with too few clamps is solved pretty easily by putting some stops on the ends of a few tubafores and cutting some wedges. Then just drive the wedges between the stops and your panel… poor man's bar clamps


----------



## GregD (Oct 24, 2009)

> Thaks guys for all your help, but I feel that sometimes you just say No no matter what. I do not think there a featherboard in the world strong enough that would close a shallow grove needed for a spline (probably 1/4" to 3/8") in hard maple ( see OP ). Even if there was such featherboard it would be impossible to push anything through it.
> 
> - 716


I wasn't saying "no no matter what", simply clarifying the concern. I would agree that what you propose is likely just fine, provided your groove does not get very deep. I've done it myself. But it is also true that you could completely eliminate the concern by raising the featherboard above the table by a distance equal to the depth of the groove. This has the added advantage of doing a better job holding the work flat against the fence.

But the most important message is that these splines are not going to be helpful in getting you good results for your panel glue-up. Not using splines, practicing the glue-up, straight rip cuts, and alternating the rips face up / face down to compensate for the saw blade being less than perfectly perpendicular to the table are going to help you get good results in your panel.


----------



## 716 (Nov 22, 2015)

> and alternating the rips face up / face down to compensate for the saw blade being less than perfectly perpendicular to the table are going to help you get good results in your panel.
> - GregD


What about the wood pattern/color/knots etc ? Shouldn't it be paramount when choosing the right side up not the technical aspects of the tools.


----------



## GregD (Oct 24, 2009)

> What about the wood pattern/color/knots etc ? Shouldn t it be paramount when choosing the right side up not the technical aspects of the tools.
> 
> - 716


These are two different things and not mutually exclusive.

Figure out the arrangement of the boards you like best by whatever criteria is important to you. So now you have how you want all the boards to go together; which side is the up side and what the neighboring boards will be. For each glue joint, rip the board on one side of the joint good side up, and rip the board on the other side good side down. These are skim cuts; you only need to remove about 1/16", just enough to ensure the entire thickness of the wood is cut on this skim pass. This way, even if your saw blade is several degrees off from perpendicular to the table, when the two edges are glued together the assembly is flat - the error cancels. Otherwise the error will double and there is a good chance that the glued-up panel will be cupped.


----------



## Nubsnstubs (Aug 30, 2013)

Do what OggieOglethorpe suggests. If he was around for that bit of advise back in '92, I'd more than likely still have all my digits on my left hand….. Blind cuts are extremely safe unless you don't set up a your stops…. ........ Jerry (in Tucson)


----------



## 716 (Nov 22, 2015)

> If I didn t have a router and wing cutter, I d skip the dado end and use a rip blade.
> 
> Plunge and stopped cuts are safe on a table saw if you re using a stop block at the ends of the cut. For a plunge, the infeed end of the board needs to be against the stop as you lower the far end onto the blade. For a stop, the outfeed end needs to be against a stop as you lift off the blade.
> - OggieOglethorpe


How would you make a stop for a long board ?


----------



## Nubsnstubs (Aug 30, 2013)

Infeed and outfeed tables. Could even mount them to your fence with clamps and long boards. ..... Piece of cake…..... Jerry (in Tucson)


----------



## xeddog (Mar 2, 2010)

I don't think anyone has mentioned that a stopped groove cut on a table saw will have a few inches on either end that will be tapered and the spline will not fit in. Maybe not a big deal in the grand scheme THIS time, but in some situations it could be.

Wayne


----------



## 716 (Nov 22, 2015)

> I don t think anyone has mentioned that a stopped groove cut on a table saw will have a few inches on either end that will be tapered and the spline will not fit in. Maybe not a big deal in the grand scheme THIS time, but in some situations it could be.
> 
> Wayne
> 
> - xeddog


Because it is a non issue. Take a knife and cut off corners of the spline and problem solved


----------



## 716 (Nov 22, 2015)

OK, Thanks those who said it is very straightforward.
Doing this way is perfectly safe and much more accurate than just edge gluing even with cauls with the crooked boards I had. Plunging onto the single dado blade, raising up…. the blade did not care. I actually don't see how a blade protruding 3/8" from the table could kick back that heavy board. If you make a mistake the blade just cuts the piece in the way you did not want.
And gluing with splines is so much fun when you see two cupped and croocked boards compensate each other after you put the spline in and hit a couple of times with a mallet.


----------

