Entry hall table for a niece: Part 11

[Derek Cohen]

The process of attaching of the legs was completed by the addition of two screws in the sliding dovetail base.


Why add screws? The screws are not to prevent the base sliding back (an elongated hole actually encourages this). It is just to prevent the base twisting in, and breaking out of, the socket since there is no glue there to prevent any lateral movement.


The force comes from the splayed and angled legs. They will want to cant outward, and this becomes more so when the three drawers are filled and a vase of flowers is placed on the top of the table.


I thought that it is worth mentioning the screws used and how they were inserted.


The screws are 1" long brass tapered wood screws. The drill bits are also tapered to match. These ones include a countersink and depth stop.


https://i.postimg.cc/jSntn8Ks/1a.jpg


The plan is to drill the hole for the screw through the base and into the case, and then widen the hole in the base. This will permit the base to move with expansion and contraction. In this case 2mm each way.


A wider drill bit (and depth stop) ..


https://i.postimg.cc/SK0q6WNc/3a.jpg


Before inserting a screw, especially brass screws, they are dipped in a little wax. This is wax for lubricating bandsaw blades ...


https://i.postimg.cc/3wghnddV/4a.jpg


Here is the widened hole ...


https://i.postimg.cc/mk6Wt95z/5a.jpg


The gap around the screw ...


https://i.postimg.cc/dQWYHMVs/6a.jpg


https://i.postimg.cc/LXDpFwkV/7a.jpg


The second screw is on the other side of the leg. This is positioned about half way between the end screw and the glued toe.


https://i.postimg.cc/Wz4PN8Xc/8a.jpg


Regards from Perth


Derek

[Gary Focht]

Does the conical shape of the screw head, fitted into the conical countersink, really allow for movement? I thought screws with a pan head (flat bottom) were normally used in these types of applications.

[Malcolm McLeod]

Does the conical shape of the screw head, fitted into the conical countersink, really allow for movement? I thought screws with a pan head (flat bottom) were normally used in these types of applications.

My suspicion would be that the screw could actually bend enough to relieve stress across the distance involved. The (trapped) head would move with the leg-base; the other end - locked in the case - can't. But there is room for the screw shank to move relative to the base. And now I'll shut-up and let the designer respond.;)

[Derek Cohen]

Does the conical shape of the screw head, fitted into the conical countersink, really allow for movement? I thought screws with a pan head (flat bottom) were normally used in these types of applications.


My suspicion would be that the screw could actually bend enough to relieve stress across the distance involved. The (trapped) head would move with the leg-base; the other end - locked in the case - can't. But there is room for the screw shank to move relative to the base. And now I'll shut-up and let the designer respond.;)

The screw choice was raised yesterday, and I have been pondering on this. I must admit that I chose the screw first as a wood screw and that it could be recessed out of sight. My thoughts were on a wider hole for movement, and did not consider whether the conical countersink would limit movement. The answer is "I don't know". Malcolm has a good point, which also occurred to me. To be safe, I plan to swap out the screws for round heads, and shape the countersink into a flat (using a wider forstner bit).

Regards from Perth

Derek

[James Pallas]

Subject is worth some discussion. When confronted with the same issue I have extended the countersink with a gouge to make it oval. You then may want to wax the bottom and dovetails of the baton. If finish were to get in the dovetail it would be glued. Age old problem with lots of tried solutions. I try to think about it and do something to try and mitigate it somehow. I have never found anything that gives me any great confidence that the issue is solved.

[Derek Cohen]

Subject is worth some discussion. When confronted with the same issue I have extended the countersink with a gouge to make it oval. You then may want to wax the bottom and dovetails of the baton. If finish were to get in the dovetail it would be glued. Age old problem with lots of tried solutions. I try to think about it and do something to try and mitigate it somehow. I have never found anything that gives me any great confidence that the issue is solved.

That is an interesting solution, Jim. I went another way. It would be interesting to hear from others.

New screws ....

Okay, so I decided that the wood screws were a mistake. They would prevent movement rather than permit it. So they had to go.


This is the exchange screw: a 12 gauge stainless steel wood/metal screw with an all-important flat/domed head.


https://i.postimg.cc/g2xXHPdZ/1a.jpg


The plan was to use a 3/4" forstner bit. This would leave a wide, flat area for the screw head to move along. The range of movement would be the same as before, about 2mm each side of the screw.


A MDF template was made to guide the forstner bit, as it had no support in view of the existing hole ...


https://i.postimg.cc/4xjK8FNF/2a.jpg


Drilled to depth ...


https://i.postimg.cc/nL7XNYXV/3a.jpg


A steel washer added ...


https://i.postimg.cc/Qt3FD97Q/4a.jpg


Done ...


https://i.postimg.cc/PxQP5XbB/5a.jpg


I had only 15 minutes after work today, but on the weekend, when I get back to this build, I plan to add a third screw behind the front leg.


Regards from Perth


Derek

[James Pallas]

Derek, That is as good a solution as any. I seen a few ways over the years to deal with the issue. I’ll be interested to see further solutions.

[Gary Focht]

I think your solution with a washer is superior to elongated holes with screw head to wood contact. Neatly done.

[Derek Cohen]

Thanks Jim. Thanks Gary.

I put the last screws in after work. That will free up this weekend to concentrate on building the drawers.


There are three screws. The one at the toe is fixed and there is no play for any movement. The two at the rear can slide 2mm each way.


https://i.postimg.cc/vmGy4X2N/1a.jpg


https://i.postimg.cc/3xX7rz1G/2a.jpg


Regards from Perth


Derek

[Andrew Pitonyak]

Derek,

You show us all these great and awesome things and this is what I focus on.... that big orange thing :



https://i.postimg.cc/SK0q6WNc/3a.jpg


I bet that does a great job of holding and not slipping. I love it. Now i need to find one like it. Very nice. Any suggestions on where to find such a thing?

[David Bassett]

... that big orange thing... Now i need to find one like it. Very nice. Any suggestions on where to find such a thing?

It looks, from the photo, like the one Joel sells:

https://toolsforworkingwood.com/store/item/EE-800-2300

(I notice not all customers are happy with it, though apparently Derek finds it useful or has a better version.)

[Andrew Pitonyak]

It looks, from the photo, like the one Joel sells:

https://toolsforworkingwood.com/store/item/EE-800-2300

(I notice not all customers are happy with it, though apparently Derek finds it useful or has a better version.)

Thanks David. I knew I had seen something similar before, but could not find it.