Pinch Dogs how to make then and how to use them

[ciladog]

This is a link to a video that I made about making and using pinch dogs old school. I know it looks easy to make them but try it. It is not as straight forward as it looks. Getting the geometry correct is a challange. Let me know how you make out.

[Glenn]

At 1:05 he says the geometry is very important. The outside corner from the back to the legs must be 90*, and the taper is on the INSIDE. You can see them in action at 2:47. At 5:03 he shows a hand forged piece with the tapers on the OUTSIDE with a view at 5:31 of both tapers to the outside of the leg.

I called Irnsrgn a 3rd generation blacksmith that also does woodworking and he confirmed that the taper MUST be to the inside of the pinch dog in order to push the wood together as it is driven into the wood. He went on to say that is hte taper was to the outside, it would push the wood apart, due to the configuration of the taper.

The only issue I have is at 4:44 when he puts the iron into the vise at an angle, then tries to turn a 90* bend on the stock. The resulting bend will have to be tweeked in order to become 90*.

An internet search shows ALL the examples I looked at with the taper to the inside. That is to say the leg is 90* to the top and thicker at the top of the leg than the point. Just as is shown in the video at 1:05.

[Bigred1o1]

nice vid i have a bucket of these that i found when cleaning out one of our out buildings and i had no idea this is what they were for thanks
i had always thought they were for stoping splits in beems

[Timothy Miller]

Thank you for takeing the time to make and post this video. I learned about a new tool that always makes me happy.

[Frank Turley]

A good vid. It reminds me of when I was in North Carolina making a few "log dogs" for the log cabin builder, Peter Gott. We only had some 1/2" round M.S. but it worked OK. The wedge shaped tapers were at right angles to each other, and the dog was about 24" long. They held the logs from moving around while the logs were being worked on. Peter used squared up logs with the half-lap corner joints.

[Mike R]

Thanks Ciladog

I have never used those befor but I will have to give a try to making them and using them for glue up.

[ciladog]

An internet search shows ALL the examples I looked at with the taper to the inside.

Glenn,
You are correct in that the taper must be on the inside of the leg.

When I adjust the geometry at the anvil block the taper is pushed inside and the leg becomes straight on the outside.

That is why I said it is not as straight forward as it looks. Try forging one and you will see what I mean.

[ironclad]

nice vid, looks interesting.

[SmoothBore]

I've seen a similar tool, with the wedge on the outside, ... that's used by Wheelwrights and Coopers, ... to spread Barrel Staves, and Wheel Felloes, during the assembly process.

I don't remember what they're called .....


.

[Fe-Wood]

Spread dogs?

[34557564]

Cool video, I had never seen those before.

[Tom Allyn]

A similar device called a log dog is used in hewing timbers. The tips of a log dog are typically formed perpendicular to eachother so that each tip penetrates the wood in line with the grain. See link.

http://www.fhwa.dot....ge21.cfm#fig097

[tomhw]

There was another similar tool used to hold logs together temporarly to make a raft back in the days of steam boats on the western rivers. The rafts were tied together with rope and pegs to travel. A timber raft in the old days could be a half mile long and required a tow-boat at each end to navigate the rivers. Small rafts could be managed with a sweep oar at each end.

[pkrankow]

I tried this today, out of garage door spring, so probably too small of material. Anyways I made the points, then formed a Z, based on U-bolt plans in an out of date book. I then made sure the points were the same length, heated the crossbar and twisted it to align the points, and flattened the cross bar some.

Worked good, but I am going to try again later in 3/8 round mild.

Phil