A friend just showed me this adapter:


It is for connecting a bit used in a bit brace to a boring machine:



This would allow you to use your entire set of brace bits in your boring machine for when you need a different sized hole for your project.

Here is the offer, if you are interested in having one of these adapters, please make a post into this thread with your name and email address. Or email me privately and I'll start a list of names, and see how many are interested.
I'll begin now to create a measured drawing of this and take it to my machine shop and see how much they would cost to be reproduced.
And I'll make them available to all, once done.

Jim Rogers
email: jrsawmill (at) verizon (dot) net

If I've done it right there are more pictures in my album of this, at:
http://s24.photobucket.com/albums/c14/Jim_Rogers/Adaptor%20album/?albumview=slideshow

I'd be interested Jim, finding smaller boring machine bits hasn't been easy.


Dave

Me too, Jim. Will you have them by September? 5 maybe. Joinery will be starting in Sept. Tim

Hopefully, I haven't spoken too soon. It seems that this type of tapered square slot in the end is something that is very hard to do. My regular machine shop guy can't do it.
He has suggested I seek another shop who has the equipment to do it. And I just got a call from them that they sold their machine to another company. But I have that companies name and number and may visit with them today....

I'll keep you posted....

The more that say they are interested the more I want to do this....
I'll be taking this adapter with me, to show, tomorrow when I do a tool run to several shops, and Heartwood school....

Jim, I was wondering how they did the tapered square hole. Share that when you find out. Thanks, Tim

I, too, am interested in what type of machine. The shop up the road from me would probably have it, they have everything.


Dave

Well, I didn't get a chance to go to the new machine shop yesterday, but from what I understand they first bore a small hole the size of the bottom of the tapered square and then use a machine that is called a EDM. It burns out the rest of the metal with an electrode the shape of the taper, while the stock is in a tank of some type of oil. I haven't seen it done, yet.
But I will be going there either Friday or Monday morning to start talks with them.
I was cautioned that this could be an expensive process to do....
We'll have to see....

a friend of mine thinks he can do it with a broaching machine..
if all fails on your end Jim, let me know the dims and I'll pass them on to my bud

Thanks for the thought... I'll let you know...

Yeah, broaching is the way to go if doing a number of them. You start by boring a round hole and then a broaching machine pulls a broach through the hole. The broach is sort of a shaft with teeth. The broach teeth are in the shape of a square, but tapper ever bigger as you pull the broach through the hole. Each time a tooth passes through the hole it cuts the square bigger They make sockets that way (for the wratchet drive). It's how you get splines inside a gear or other part. I assume it's how you rifle a gun barrel too.

Someone I'm sure already has a square broach that will work. Have the blanks machined and then send them out for the broaching. Too bad it's such low quantities...costs more. It's a matter of finding one that will do a small job. There are plenty of shops listed on the web, but I'd look locally first to try and save the shipping.

It's not just a square hole, it's a tapered square hole. Broaching probably isn't going to work, unfortunately.


Dave

I wouldn't be apposed to making it a two piece unit, so that we could broach through it. And/or making it a little longer to that there is enough stock to make the spot where the shaft could enter the socket end... or a bit wider in diameter...
I've planned to go to the EDM machine shop Monday morning and see what they say.
After that I may go a different route, we'll have to see....

Jim, just a thought, could they machine the cylinder, cut it in half length wise, machine the interior, weld it back together and turn the welds off. Or start with square stock and than turn after it's welded back up. Is there any evidence on the original as to how it was made? The first thing I though of was it forged some how. Just checking.

I am using a chuck off a breast drill for an adaptor now, I use it with a new 1-1/2" bit. I want one for peg holes, if you make it longer I am wondering if a 12" long bit will have the the clearance and capacity in the boring machine? Tim

I got a chance to see the adapter on thursday when Jim was out this way. I would say the original was forged. I looked for casting marks, but I didn't see any, and it doesn't look like cast iron. There are several different ways to approach the problem. They run into one of two problems, either too many steps to make it, or an expensive process. I've got one of my problem solvers working on the dilema right now, and we have three angles of attack we are working on, depending on the final product that is desired. One of which I think can result in a very reasonable price.


Dave

Bore a hole and edm for low quantity. I wonder what a blacksmith could do to make that hole/shape. Maybe an old time blacksmith. I actually saw a tool company on DIY's "Cool Tools" the other day where they hand forge all of their garden and other tools. There might be a place to start. Forge the hole and then machine/grind the rest.

Any luck at the EDM shop Jim?

I've got a friend that is going to machine a die to use in an attempt to forge one. You have to drill several holes of different sizes, or better yet, have a tapered drill made. You won't be able to move too much metal, so it will have to be fairly close. If the forging works, we could probably set up some dies for the trip hammer at the forge.


Dave

They did send me a quote yesterday, it was shocking, even for a good quantity. I'd have to get $86 each for them; to have them made by a EDM process.
Dave, see what you can do to make some, call if you need to....

I'm not surprised about the EDM, I was told it was a very slow process. My friend Don and I are working a couple of angles, but, as I like to say, Don moves at the speed of Don.


Dave

I'll contact my regular machine shop and see what else we can come up with. The two part idea seems like it might work. That would be to cut the socket cylinder in half, mill out the tapered slot, in each half, and then put it back together. I'll have to ask if this would be something that would work.

I would TIG weld it back together for a tough, consistent penetration weld that is not brittle. If not under a lot of stress and impact loading, it should hold up.

I will mention it, thanks....

I had a meeting with my machine shop guy this morning.
We need to find on the internet the exact angle of the ends of the bits, for the tapered slot to hold it in the adapter. He measured a bit I had and said it was somewhere around 3.25 to 3.5 degrees. But using my measured drawing I have it as 4.29 degrees. So probably my drawing is wrong.
He suggested I do a search to find the standard for these bit ends. These are the bits we use in a bit and brace.
Who invented this?
What is the correct name for this bit end?
What is the correct angle if you know?
Thanks any help would be appreciated.

Jim Rogers

Jim,
1.I think it's going to be easier to measure bit angles on an optical comparator. For the internal angle of the adapter, can you cut the one you have apart? Do you own it? Then measure the angle of that one.

2. Not sure if you want the angle to match as the bit might get stuck. They might have to be slighly different.

3. Consider boring a through hole as well so that if a bit is stuck, you can take off the adapter and insert a pin and knock the bit out.

4. Where does that set screw hit? On the shank below the pyramid?

Brad

I went to a local industrial supply house and got a new bit for him to use in his measuring device.
And I dropped it off this morning. He didn't have time to measure it as he was doing production work, because one of his employee's was out sick, today.
He is planning on creating the socket in two halves and then inserting the two halves into a shell to hold it, and the shell will have the end for going into the boring machine chuck.
This sounds like it will work, because milling out the tapered slot in the two halves will have square corners for holding the bit end.

3. If the bit gets stuck then you maybe able to remove the two halves from the shell to release it.

4. the set screw presses onto the pyramid.

I found, yesterday, a lot of info about braces and manufacturers of braces but not a lot of info on the bits or what the angle was. Hopefully he'll be able to measure it and create a sample for me to test before we do a production run.

More info later when I have it...
But in the mean time if anyone know where to find the angle in a set of bit standards or how to find the bit standards; it would be great to know....

Thanks..

Jim Rogers

Jim
Would a 4 jaw chuck hold it. I have one somewhere but couldn't find it on a quick search.
I would think a blacksmith could do something that would work well also.

Bob

Not sure, find yours and try it....