E-cab luvin

[chunkstyle]

I ask this because the tenons that were dropped from my test twd. (the one that Kenneth also ran) were 55% of .75". In other worlds, that means that the resulting tenon was .4125" thick. That would require a .4125" wide corresponding dado, if fit tolerances are set to zero, in the adjoining part recieving the dado would it not? If this is the case then why were my .25" long tenons dropped on my parts with a bit daimeter of .253"?

When I speak of tenon length I am referring to how far off the edge of the panel the tenon extends.

When I think of dado I think of a grove that is milled into the face of material by a DADO set on a table saw or a router bit in a router (or spindle).

I am assuming that what TWD meant by dado diameter is actually referring to the width of the dado.

Dado depth is usually determined by tenon length and vice versa in my way of thinking.

Boundary box is a term that I learned from the Thermwood shop to describe the pocket geometry outline that is used to create pocket cuts.

""It is not the tenon depth that dictates what tool is chosen for an operation. The tool is chosen based on the the dia. of the dado (tenon thickness). For example: if your dado is going to be .375, then a tool dia. that can cut this dia. within two passes is selected (tool setup for rout/dado with dia. .374 and smaller)." - TWD

Am I interpreting this statement as meaning that the tool chosen to mill out the pocket for the tenon shoulders (the boundary box) is determined by the dado diameter (guessing that means dado width since they refer to tenon thickness)?

If so then the question is still unanswered in my mind. Why didn't the .253" bit cut the shoulder if it can cut the .4125" wide dado for the same tenon?

Or does it make sense to try and understand it if you find out that .25" diameter works?

Is this considered fighting the program logic?

[chunkstyle]

Gary,
After reading yours and Thermwoods logic I'll think about it in your terms. I think you are saying that tenon length (or dado depth in construction settings) determines the boundary box (possibly referred to as a dado?) and that is what has to be cut by a bit of smaller diameter. Makes sense to me and jives with what I have observed here. The TW explanation manages to confuse me a bit.

All right, I think I've managed to suck the life out of this issue, nuff said.

Tim

[chunkstyle]

Ok. Ok. really this is it...

Gary,

You and TW are using the term Dado for that shoulder cut operation? I see the code for the milling of those two parts has the operation listed as a dado. This is where the confusion is coming from for me.

Someone tells me I need to cut some tenon dado's... I think of the actual dado that will receive the tenon. Some one tells me to cut a tenon shoulder.... that might involve a Dado blade but I would be thinking shoulder cut.

It's the nomenclature of the code and not that of a shop that you were speaking in I'm guessing? Penny just dropped and I ran down to check the code on the machine's computer to see how it was describing it. Words can get confusing. I'll try and use what is being documented in the Link code and not accepted shop terms from now on.

I post this in case it might help others avoid confusing themselves as I have done.

Tim

[ken_rychlik]

I thought I understood it, but now I'm confused.

[Gary Campbell]

Tim....
You are overthinking this. You have yourself confused and you almost have me there too. I will ignore your answers that turn into questions and explain it the way that I know it. My terminology may not match yours, but please bear with me.

I refer to all dado cuts as rectangular geometry. Just as they are shown in the eCabs or SB Link nest. I am not going to mention the amount that is added to a dado rectangles length. (1/2 bit diameter to each end)

Assume .72 material, 55% tenon thickness(.396) and .375 dado depth, .010 fit clearance, .020 depth clearance

A tenon dado (located on the end of a part and forms the tenon) is the dado depth wide and material thickness minus tenon thickness deep. .375 wide by .324 deep by whatever length. No clearance is applied to this geometry Leaves a tenon .396 thick by .375 long


A pocket dado (usually on a cabinet side to receive a tenon) is the tenon thickness (.396) plus the fit clearance wide, dado depth (tenon length) plus the depth clearance deep. .406 wide by .395 deep. All the clearance settings are applied to this geometry.

How this applies to tooling are in my folllowing recommendations:

When designing for a single bit, then you select your bit first.

I assume either 1/4 or 3/8, I prefer 3/8. I will give parameters for both.

Your dado depth must be the same or larger than the bit diameter. (does not apply to full dados)

Your tenon thickness plus fit clearance must be equal or greater than the bit diameter. For efficient machining, I recommend that the tenon thickness (or the width of any dado) not be greater than 1.8 times the bit diameter. I think that due to small bits that Link users can pocket dados, but I do not chose to use this feature, if it exists.

Thats all ya get till you buy the video!

[Gary Campbell]

Tim...
To clarify my terminology, here is a screen shot from an eCabs nest:

[chunkstyle]

Thanks Gary,

Picture is worth a thousand posts.

Make sure you tenon length is greater than your Rout/Dado diameter.

Make sure your full dado's and pocket dado's widths are greater than your Rout/Dado bit diameter.

Tenon's shoulders (well actually the cheek cut to be accurate) are formed by the creation of a boundary box, called tenon dados, where the width of the box is derived from the tenon length (dado depth in E-cabs construction settings).

Sound correct?

Got hung up in the use of the term dado. Lead to confusion in the explanation of the CNC operation. Probably why the TW Shop owner was using the term 'tenon boundary box'. Less confusing to explain to employees maybe. I think I've got it now.

Thanks heaps,

Tim

[Gary Campbell]

Tim...
I believe you have just snatched the pebble, Weedhopper!

Now stop over analyzing and get back to cutting!