Workbench dog hole idea - wooden screw?

[Tetsuaiga]

I am building a workbench and would like to install what ive seen called dog holes in the top.

An idea ive been thinking about is to use wooden screws, that way you could adjust the height sticking out which is helpful for very thin pieces.

Any thoughts on this? The only tricky thing might be finding a suitable size tap and die, ive no experience of using standard types.

 

[Phil Pascoe]

Probably easier to put some sort of springing on the side of a (wooden) dog so you can tap it down and it'll stay where it's put. If you're thinking really thin, the size of the thread would determine the height if you needed a flat face on the dog. I've dog holes dead square to the front of the bench on the front and back, so I'd just put an 1/8th" (or thinner) strip between them if I needed something that low.

 

[rafezetter]

I can't show you a picture but I made a dog for my moxon planer bench that had a screw in it for just such a purpose - it has the added advantage of the screw head digging into the wood a bit to stop it moving.

 

[DTR]

I have used wood screws as bench stops in the past, it works well, especially for thin stuff. I found that the screw tends to bend after heavy planing though. Also, the slot / posi cross head etc tends to fill with sawdust which you have to dig out before you can wind the screw in or out.

 

[Tetsuaiga]

Do you remember whay size the screws you used were.

I was thinking something between 1/2 to 1 inch diameter 3/4 too. Axminster has a wood tap and die of those sizes.

 

[AndyT]

I take it that you are asking about cutting threads in stout dowels and inserting them into matching threaded holes in the bench. (The previous answers were about using metal woodscrews.)

I don't think it's a good idea. You can get a matching tap and die set to cut a coarse thread in hardwood. The easiest one to find is made in China and is about £35 to £50. Vintage ones are uncommon and generally go for more on eBay.

But in practice I think it will be too slow and fiddly. There is no need to over engineer these things.

I use some short pieces of round hardwood which are a tight fit in 3/4" holes. I knock them in with a mallet. Adjusting the height is quick and easy with the mallet from above or below and they don't fall out in use.

Another option is to make square holes and fit long leaf springs of wood or metal.

Or stick to round pegs and use a spring loaded ball catch to hold them in place.

 

[Phil Pascoe]

Do you remember what size the screws you used were.

I was thinking something between 1/2 to 1 inch diameter 3/4 too. Axminster has a wood tap and die of those sizes.

He meant wood screws as in screws for wood, not wooden screws.

 

[Tetsuaiga]

Thanks. I think i'll probably be best with the conventional ones rather than unncessarily risking wasted time and possible dissapointment.

 

[Phil Pascoe]

Another downside is of course that threading the holes would weaken them if you use holdfasts in them.

 

[graduate_owner]

If you are still thinking of screws, you could perhaps try coach screws because they come in really thick sizes. I think you would have a job to bend them. Also no slot to fill up with debris.

K

 

[JJ1]

Hi,

I don't know if this is of any use to you, but when I built my bench a while back I was undecided on what dogs to use.
Initially I made some of the following ones. They were ok but a bit of a pain as you had to keep giving the wire 'spring' a tap with a hammer to either loosen or tighten the bench dog in the hole. Also if planing thin stock you had to push it down so far and it became fiddly to get it back out.

I decided to make some different ones, seen below, and I couldn't be happier with them. I've since made some much thinner ones (not shown) with the tops being just a few millimeters thick which allows planing and holding very thin stock. It's just a question of grabbing the most appropriately sized ones for the job in hand. An added advantage is they grip the work superbly (10 degree bevel on the face side), drop in place and remove in a split second. They also turn in the hole to grip anything that's not parallel too.

 

[John15]

+1 for the capped dowel system above. They are easy to make and hold the work firmly.

John