Blade Angle for cutting inlays using Excalibur 21 (Taiwan Mfg)

[Blaughn]

You will have to forgive me.  I worked my way through college as a machinist manufacturing optical equipment where 10 thousands of an inch precision was law.    I realize that the scroll saw is not in the same category but.......

I am doing some inlay and after using the trial and error method of setting up blade angle.  My thought process:  "There has to be a better way!" 

I know, through trial and error,  that with .375" material for project and .375" thick material for the inlay and a a #3 FD ultra reverse blade I need a blade angle of 1.1 to 1.2 degrees.  Here are the challenges with my Ex 21:

1.  My table is slanted toward me 4.5 degrees to relieve back strain.

2.  There is no reliable surface on the arm or the blade holding mechanism that allows the digital angle tool (DAT) to repeatable measure the blade angle.

3.  Depending on the thickness of the material .1 degree can make or break the project (inlays too tight or too loose).  

Here is what I came up with:

Using the front table attachment bolts I put a 4mm Allen wrench in the pocket - turned it until a flat surface of the Allen wrench was facing toward the front of the table - then measured and marked 5 7/32.  (the distance is not critical as long as it is consistent from each bolt)  I repeated this on the other side and scribed a line.  Picture 1

Aligning the DAT with that (very faint) scribed line and pressing the "Zero" button this zeros out the influence of the forward tilting table.

Finally I place the angle detector, magnet side to the tensioned blade and put a piece of round stock under the DAT.  The round stock allows the DAT to align with the blade more easily.  Note:  It is essential that the DAT remains parallel to the scribed line or the table tilt will introduce error.

Using this technique I am able to hit the mark or be within .1 degree and reduce the trial and error.

Now - to count the number of coffee grounds in a scoop of coffee........

[kmmcrafts]

If I remember correctly you can also mark the edge of the board with a line then measure the thickness of the board and make another line on the edge of the board the same distance from the first line that is the thickness of the blade.. Place the board at the back side of the blade and line it up with whichever mark then angle the saw blade until the bottom or top angles to the other corner of the mark.. 

That doesn't sound right? I've honestly never done this but read about it or seen a youtube video on how to do it something like this.. maybe someone else would chime in that does it this way..

[OCtoolguy]

@Dave Monk, you're the inlay pro. Waddaythink?

Edited October 4, 2022 by OCtoolguy

[kmmcrafts]

45 minutes ago, OCtoolguy said:

@Dave Monk, you're the inlay pro. Waddaythink?

Not sure why your tag didn't work.. It should highlight his name in blue as a link. Someone tagged me the other day and I just stumbled upon it as it didn't actually tag me.. fortunately I ran upon it anyway but. To have it actually tag it has to be highlighted like this. @Dave Monk Doing this on my computer I notice that it pops up their name and in order for it to actually tag them I have to click on the name when it pops up.. maybe that is what happen to you when you tagged him..

[OCtoolguy]

1 hour ago, kmmcrafts said:

Not sure why your tag didn't work.. It should highlight his name in blue as a link. Someone tagged me the other day and I just stumbled upon it as it didn't actually tag me.. fortunately I ran upon it anyway but. To have it actually tag it has to be highlighted like this. @Dave Monk Doing this on my computer I notice that it pops up their name and in order for it to actually tag them I have to click on the name when it pops up.. maybe that is what happen to you when you tagged him..

I figured out that when the name pops up, you have "select" it and then it turns blue.  Lesson learned.

[Dave Monk]

I'm far from an expert at inlay.  @Jim Finn has done a heck of a lot more inlay than I have. Looking at this scientifically is above my pay grade.  I pretty much use the same thickness of wood  and the same blade for every inlay. I use my Pegas saw almost exclusively for inlay so once I get it set I can leave it alone.  The wood I use is .4" thick.  I use a #5 Super sharp blade on my inlays.   I will zero my Wixey level on the table and then stick it to the very back part of the arm and set it to 1.5 degrees.  The hardness of the wood can make a difference. The wood grain can effect angle. At times I have a tendency to push sideways. That really changes things.  If I am doing a box lid with three letters on it none of them will fit exactly the same. That may be caused by my sawing skills.  

[kmmcrafts]

I know one thing that will affect your cuts is moisture content.. I may be wrong but I think no matter how precise you get with your angles there is going to be some imperfection because of the moisture levels in wood and so many other variables.. not to mention your cutting skills.. I think most times you're going to have to do a bit of sanding to get the fitment you need / want..

I showed a video of how the CNC guys do the inlay on another thread a few days ago.. those machines are pretty precise yet I see on the CNC forums where they have fitment issues because of the movement in the wood. You'll almost always have to sand the inlay flat so both pieces sit flush..   

[Jim Finn]

9 hours ago, Dave Monk said:

As Dave does: " I pretty much use the same thickness of wood and the same blade for every inlay. I use my Hegner saw exclusively for inlay so once I get it set, I can leave it alone.  The wood I use is .4" thick.  I use a #5  blade on my inlays.   The hardness of the wood can make a difference. The wood grain can affect angle. At times I have a tendency to push sideways. That really changes things.  If I am doing a box lid with three letters on it none of them will fit exactly the same. That may be caused by my sawing skills"

Dave and I do almost the exact same thing.  same blade and angle.  Different dedicated saw though. I find that fresh new blades cut to a tighter fit.  Using the same blade on the next inlay makes for a looser fit.  I think this is because it cuts slower and removes a little more wood.    Jim

 

[Blaughn]

On 10/4/2022 at 7:34 AM, Jim Finn said:

 

Hi Jim:

I have discovered that the Pegus clamps installed on my Excalibur have .021" of play side to side (top and bottom clamps).  The original factory blade holders share the issue.  I talked to Bear Woods about this and they told me they would send some spacers.  These have not yet arrived.  I am discovering impossible variability in the inlays.  The first pf the 3 initials for the pencil holder boxes goes all the way through, the second stops 2/3s of the way through and the third stops at 1/3 of the way. I suspect that any sideways pressure would cause the bottom blade holder to drift to the left and increase the angle of the cut causing a fit that is too tight.

I don't know for certain that the side-to-side play is the problem but it is certainly high on the list of potential causes.  I will follow up after the spacers arrive.  I have also discovered some folding knife brass washers and Teflon washers on Amazon that would serve the purpose.

My inlay project is successfully creating firewood.  

[Jim Finn]

On 11/10/2022 at 9:00 AM, Blaughn said:

..".Hi Jim: My inlay project is successfully creating firewood."  

I do a TON of inlays. (I did 30 this past week) Pretty good quality, lots of quantity. (It all sells though).  To make it easier, and a lot more like fun, try adjusting your cutting angle to a looser fit.  If you use a thicker underside wood than the background wood, and a looser fit, you can push the inlay wood up about as far as it will go and glue in place leaving the back closer to flush than the front.  This closes the kerf gap, and you can sand the front flat in a stationary belt sander. Backside also.  Learning how to fill in any gap after doing inlay is important.   I use a mixture of white glue and sanding dust and force it into any gap with a credit card. Then sand flush.  If you are having trouble with cutting straight, with little wandering off the line, cut slower and have your blade so tight it is almost ready to break. Here is one of my inlays I did for a friend.

 

Edited November 13, 2022 by Jim Finn

[Blaughn]

4 minutes ago, Jim Finn said:

I do a TON of inlays. (I did 30 this past week) Pretty good quality, lots of quantity. (It all sells though).  To make it easier, and a lot more like fun, try adjusting your cutting angle to a looser fit.  If you use a thicker underside wood than the background wood, and a looser fit, you can push the inlay wood up about as far as it will go and glue in place leaving the back closer to flush than the front.  This closes the kerf gap, and you can sand the front flat in a stationary belt sander. Backside also.  Learning how to fill in any gap after doing inlay is important.   I use a mixture of white glue and sanding dust and force it into any gap with a credit card. Then sand flush.  If you are having trouble with cutting straight, with little wandering off the line, cut slower and have your blade so tight it is almost ready to break. Here is one of my inlays I did for a friend.

My problem is that the angle of the blade changes after setting it due to the ability of the blade clamps to shift laterally by up to .021" left and right each (Top and bottom).

I can set the blade angle but as I cut angle changes dramatically.  With the combined freedom of movement the blade angle has the freedom to change by .6 degrees.  I am in the process of trying to restrict that freedom of movement by inserting spacers.

I love your work, by the way!  It is spectacular!

[Jim Finn]

2 hours ago, Blaughn said:

My problem is that the angle of the blade changes after setting it due to the ability of the blade clamps to shift laterally by up to .021" left and right each (Top and bottom).

I can set the blade angle but as I cut angle changes dramatically.  With the combined freedom of movement the blade angle has the freedom to change by .6 degrees.  I am in the process of trying to restrict that freedom of movement by inserting spacers.

I love your work, by the way!  It is spectacular!

Thank you for the kind words. I think the reason I could do inlay well, at the start, is because I was VERY adept at following the line when cutting out toys. The very first inlay I tried was good enough to sell. (Attached is a photo of that inlay). Maybe the reason your angle changes while cutting is too loose blade tension or any sideways pressure as you cut. These were my early on problems. 

[OCtoolguy]

Outstanding work Jim!

[Scrappile]

So seriously I sit here thinking if .0# of a degree makes that much difference ... I am going back to building another street organ...

[Blaughn]

13 hours ago, Scrappile said:

So seriously I sit here thinking if .0# of a degree makes that much difference ... I am going back to building another street organ...

The degrees of freedom for side-to-side movement of the blade in the Pegus holder is .024" (.6mm) on the upper clamp and the lower clamp. That is not the angle.  That side to side movement impacts the angle by up to roughly .5 degrees.  When doing inlay .5 a degree is significant.