Author Topic: Domino Selection Chart/Table  (Read 645 times)

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Offline smorgasbord

  • Posts: 27
Domino Selection Chart/Table
« on: January 10, 2022, 11:38 PM »
While there are some threads here, I didn't find anything like a Selection Chart to use a reference, even if just as a starting point.

From what I've read, there are various factors at play: The thickness of the stock being mortised, of course, but also whether that stock is hardwood or softwood or plywood. There are also length limitations for carcase style corner joints. And there are strength considerations for frame-and-panel (face-fame style) joints, but not for edge to edge glue alignment usage.

I started to make such a table, but before I get too deeply into it, I wanted to get some feedback on whether I'm on the right track. What other considerations do I need to include, if any? No table will be definitive, of course, and personal preferences/machine availability may shift tenon choice from any value. Stacking narrower tenons may be viable if you don't have a 700, but then there might be length considerations.

At any way, any suggestions on the follow would be appreciated


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Offline 4nthony

  • Posts: 97
    • Slack for Recon Tools
Re: Domino Selection Chart/Table
« Reply #1 on: January 11, 2022, 12:30 PM »
I think most just follow the rule of thirds as their starting point.

12mm -> 4
15mm -> 5
18mm -> 6

Sometimes, it depends...




Offline smorgasbord

  • Posts: 27
Re: Domino Selection Chart/Table
« Reply #2 on: January 11, 2022, 12:50 PM »
I think most just follow the rule of thirds as their starting point.

Sure, but that's just the starting point. And for the example given in the video, he's doing long grain to grain gluing, so you don't need/want thick tenons. But, if you're doing kitchen cabinet door frame and panel, or entry door frame and panel, then your glue joint is long grain to end grain, so the ONLY strength comes from the tenon, in which case you want to have the tenon strength be as great as the mortise strength. If one is stronger, the weaker one is, well, your weak link. Hence the two sections in my table.

Offline 4nthony

  • Posts: 97
    • Slack for Recon Tools
Re: Domino Selection Chart/Table
« Reply #3 on: January 11, 2022, 01:59 PM »
...then your glue joint is long grain to end grain, so the ONLY strength comes from the tenon, in which case you want to have the tenon strength be as great as the mortise strength.

I think someone debunked the myth that long grain to end grain glue joints are inherently weak, but that's its own can of worms best left to people who enjoy that kind of debate. Fast forward to 5:55.



What I took away from Sedge's video is that he chose the 5mm domino so he wouldn't have to change the depth setting and risk blowing through the other side. It was more about the length of the 5mm domino (30mm) rather than the thickness.

I've only been using my Domino for about a year so I don't have the knowledge of other more-seasoned users, but I tend to rely on loose tenons for alignment rather than strength. However, there is added glue strength because the long grain of the tenon is adhered to the long grain in the workpiece (inside the mortise).

I don't know how much physical strength the actual domino provides, at least when considering the smaller sizes used by the DF 500.


Offline mattbyington

  • Posts: 772
Re: Domino Selection Chart/Table
« Reply #4 on: January 11, 2022, 06:21 PM »
For me, I keep it simple and use 5mm x 30mm dominos on almost all of my projects. I only use the 4mm ones in miters or really thin stock like on drawers. And I only use big ones on thick stock like 8/4.

The reasoning I have for this is that 5mm x 30mm is the longest and largest domino that you can use and not change your plunge depth settings. The reason is because half of the 30mm length is 15mm, and if you're working with 3/4" undersized plywood, or hardwood milled to .75", you can keep the depth setting at 15mm on the domino and cut mortises in edges, ends, and faces without changing a thing.

I've found this speed, repeatability, and not forgetting that my plunge depth was set too deep to really save me time and frustration in the shop.

A lot of times dominos are more for alignment, and even the 5mm dominos do add quite a bit of strength in joints.

Just my $.02.

Matt

Offline squall_line

  • Posts: 1235
Re: Domino Selection Chart/Table
« Reply #5 on: January 11, 2022, 06:23 PM »
However, there is added glue strength because the long grain of the tenon is adhered to the long grain in the workpiece (inside the mortise).

^ This.

The tenon is providing additional glue surface and cross-grain linking with shear strength compared to tensile adhesion of the end grain to long grain of just gluing the panel edges to each other.