Through shelf holes?

[Joe Dusel]

Here's a question for the CNC savvy. I'm trying to design a job to have as few flip-ops as possible. I have a few cabinets with center partitions with adjustable shelves on both sides and a few with fixed shelves on both sides using blind dados. If I make my shelf pin holes or blind dados more than half of the thickness of the panel material is the CNC software smart enough to just drill or route through the panel so that it does not require flipping?

Thanks,

Joe

[jason galbraith]

Don't know if this helps, but when we've got a partition with adj. shelves either side, as long as the shelves are on the same lavel, the holes will drill straight through. I don't think that making the holes deeper than half the depth will achieve what you want.

[David Egnoski]

I'm not sure about the opposing blind dados, haven't come across that yet. If the shelf pins holes are 1/2 the thickness of the material, or slightly more, they will drill through.

[Joe Dusel]

Thanks for the info. I wish I had a Thermwood router in my own shop to check these things out.

Joe

[Michael S Murray]

Joe you are correct on the shelf holes but on the blind dado you have to reduce depth or your tenons would hit befroe seating correctly. I suppose you might try to set the tenon and a little less then half material and then allow extra depth clearance to drill through, but I have not thought that through or tried it....

[Paul Ford]

Just a thought with the dado which I will have a look at for you today, you may be able to set the dado depth to less than half the material thickness then change the depth clearance to suit. I'll try to have a look at this for you later on

[Michael S Murray]

dam good idea paul........

[Paul Ford]

I just tried it and it doesnt seem to work unfortunately! It still reads it as a flip operation for some strange reason. Looking at the CNC file it is only cutting to 1/2 the material thickness.

[Joe Dusel]

Thanks much Paul! Too bad it does not work.

Joe

[Paul Ford]

No worries Joe, someone else might have another work around for it!

[Dennis Englert]

I may be misreading this, but regarding the captions where you are setting the 50% of the Material Thickness. That value is applied to the thickness of the tenon, not the length. The tenon length is set in the Dado settings under length. The Depth Clearance increases the depth of the dado, while the Fit Clearance pertains to the side clearance. The Fit Clearance basically is the same as shimming your dado blade so that the material the full dado. I would think that most conventional woodworkers cut to depth for their dados without any additional clearance. It may be a slightly different process for a mortise and tenon, since you are cutting the sides of the tenon to fit the dado, but in either case you are applying a fit clearance.

On a CNC, the additional depth clearance can be used to allow for variances in material thicknesses. Example, if you are using a blind dado and set your tenon length to 3/8". Theoretically, your dado should be 3/8" deep. But there's where the material thickness comes in. Again, on the CNC, the Z value is set to zero based upon the material thickness. The surface of the material is Z0. So if the material has been defined as 3/4" in eCabinets, the machine will make a cut from the point of Z0 (the materials theoretical surface) to 3/8" depth. If the surface or thickness of the material is not 3/4", the the dado depth will vary. If it's thicker than 3/4", the dado will be deeper; if it's thinner, the dado will be shallow. On a blind dado, the latter would cause the tenon to bottom out before the shoulder of tenon seats. Since the material thickness may vary some from sheet to sheet, you may need to allow for that with a fit clearance setting that accomodates more than just the glue so that the tenon seats.

Regarding the Shelf Pin holes, yes it will, if the holes are aligned and based on the depth. I don't believe that you need to over compensate for the depth.

Regarding the dados for a shelf, I would think not. The default setting for the inset value on a blind dado is 1", so unless that is changed, the End or Partition will almost be cut in two.

Hope I didn't interject any more confusion.

Dennis

[Joe Dusel]

Thanks Dennis. I think we were all referring to the thickness of the panel with regards to the depth of the dado. My goal is to try to have as few flip-ops as possible when I send the job out to be machined. It seems that in the case of having a "through dado" this is not going to work. Very good explanation non the less.

Thanks,

Joe

[Joe Dusel]

Well, I just got some parts cut this afternoon on Trueline's CNC. The blind dado in the partition went straight through with no flip-op needed.

Joe

[Fred Reinfeld]

If you have particular customers, drilling through a partition may not be a good idea. In our experience at the router with melamine and veneered mdf sheet goods, the bottom face blows out or splinters in the void created in the waste board from previous perimeter cuts. The flip as a product quality issue may be worth more than the rework.
Fred Reinfeld