How do you make this spline?

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Forum topic by Steamboater posted 03-29-2016 02:44 AM 891 views 0 times favorited 5 replies Add to Favorites Watch
View Steamboater's profile


5 posts in 1406 days

03-29-2016 02:44 AM

Topic tags/keywords: question

I am building a project from a photo and have hit a wall. The project picture shows the back side (Wall Side) of a picture frame and near the inside corner there is what appears to be a spline running perpendicular to the mitered joint. The spline looks no wider than 3/16 of an inch and is about 1 1/2 inches long. All my searches for miter frame splines come up with corner splines typically produced on a table saw with some sort of a corner jig. The outside edge of the frame has been routed with a table edge bit, so this type of spline is not viable. This spline in the photo however is a facial spline (Not sure of what to call it) and I am not sure of how to make it. Anyone have any ideas?

5 replies so far

View MadMark's profile


979 posts in 2061 days

#1 posted 03-29-2016 02:58 AM

Cut the spline slots on the miter gauge with a bevelled block.


-- Madmark - [email protected]

View SuperCubber's profile


1090 posts in 2892 days

#2 posted 03-29-2016 09:57 AM

Stand the side on its 45 edge, and pass it over the blade. Do the same for the other side and insert your spline.

A table saw sled, or better yet, a sled specifically for this would be easier/safer.

-- Joe | Spartanburg, SC | "To give anything less than your best is to sacrafice the gift." - Steve Prefontaine

View JBrow's profile


1368 posts in 1528 days

#3 posted 03-29-2016 02:44 PM


My approach would be that of MadMark’s with some minor but important additions. The approach I offer makes some assumptions. I assume a 1/8” thick spline and 1/8” saw blade kerf. I also assume that when you say a “facial spline” you mean the spline is visible on the front and the back of the work piece. If the thickness of the spline is wider than the saw blade kerf, then cutting the slots to accept the wider spline (3/16”) is more complex, requiring multiple and precise setups. A dado set following these steps can be used if the slot and spline are at least ¼”.

Blade. Install a flat ground blade in the table saw. The flat ground teeth of the blade should produce a flat bottom cut. Tilt the blade to 45 degrees so that a 90 degree angle is formed between the tilted blade and mitre on the work piece.

Mitre Gauge. Lock the miter gauge at precisely 90 degrees, as one would do for a typical square cross cut. Outfit the miter gauge with an auxiliary fence long enough so that the auxiliary fence will pass over the saw blade and back up the cut to prevent tear out. Glue some sand paper to the miter gauge auxiliary fence to keep the work piece from slipping. If the mitre gauge has a sloppy fit in the mitre slot, ensuring the mitre gauge is firmly and consistently pressed against same side of the mitre slot during set up and during all cuts will yield consistent results.

Length & Depth of Cut. Attach a stop block to the table saw fence and set the fence in position to define the location of the cut. Set the table saw blade depth of cut. Then make some test cuts to dial in the depth of cut and the position of cut. If a spline has already been cut and two mating test cuts are made, the spline can be fitted to the test pieces and depth of cut can be perfectly set.

Making the Cut. When everything is set make all 8 cuts without changing the set-up, clamping the work piece to the miter gauge to ensure the work piece does not creep during the cut. Some cuts will be made with the show face of the work piece away from the fence and others with the show face against the mitre gauge fence. Tear out on the back and face of the work piece will be minimized with a sharp and clean (free of pitch build up) blade and the freshly cut kerf on the auxiliary fence.

View Steamboater's profile


5 posts in 1406 days

#4 posted 03-29-2016 09:54 PM

Thanks for the great detailed instructions on cutting that type of Spline. That one is on my to do list as well, thanks for the clarity.
Unfortunately I Don’t think that will work in this situation. Perhaps my term “Facial Spline” led everyone astray. This particular spline is only about 1 1/2” long and shows on the back side only as seen in this photo. The mitered Frame stock is only 7/8” thick and 2 3/4” wide, so I am guessing the complete spline is about 1 1/2” long, 3/16 wide, and about 1/2 ” deep.
Off hand I would guess it is done with a router, but On second thought I am thinking the builder might have done this with a biscuit cutter device, though I have never used one of those myself. All these dimensions I have given are just a guess on my part. From my research I am thinking this is not a common type of spline. I am not even sure what to call it, let alone how to make it.
As always, I appreciate the input of anyone with something to say on the subject.
JBrow, thanks again for the detailed reply.

View JBrow's profile


1368 posts in 1528 days

#5 posted 03-30-2016 02:37 AM


Sorry that I misunderstood. It sounds like you want to insert an inlay. Although I do not have a router inlay kit, I think that accessory may be of some help. The inlay router kit allows you to cut the inlay pocket as well as the piece that fits snugly into the inlay pockets. The link is but one example of inlay kits available. This kit offers a bow-tie template, but you could make a template to your liking.

Also, I checked YouTube and found several videos when using “Router Inlay” in the search box.

I do not understand how a biscuit jointer would be able to make the inlay shown in your pic without a lot of what I would consider difficult work. The biscuit jointer could cut a slot in the back face, but then the slot would be curved. The inlay would have to be painstakingly crafted to fit in the curved slot or a narrow chisel would be required to square up the inlay pocket.

Although I am sure you already know, I will mention it anyway. The mitred corners on the picture frame will be inherently weak joints since this is normally a glued end-grain to end-grain joint. The spline, or in your case, inlay functions to strengthen the joint.

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