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I have a dendrochronology working at my house today trying to date the timbers. Basically they take a core sample of the wood and match the core to known growth patterns to determine when the tree was cut down. Anyways he had a guy in Germany fabricate some core sample bits years ago but the guy is retired now and he is looking have 5 or 6 new one made. The are like a hole saw without a center guide bit and then take 1/2 cores and they have a very deep reach of about 12 to 18 inches. If anybody knows of a place that fabricates specialty tools like this let me know.
 

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Here is what they look like. They are a stainless steel tube with a brazed on commercial cutter head. They are removable from the bit holder so that the samples can be pushed out with a dowel rod.
 

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That is very interesting...how does it get started without the pilot?

I don't know anybody of the top of my head, but maybe look for a Tool and Die shop possibly-they often due custom work.
 

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That is very interesting...how does it get started without the pilot?

I don't know anybody of the top of my head, but maybe look for a Tool and Die shop possibly-they often due custom work.
He nails a guide plate to the beam to stop it wandering. Just like if you want to enlarge a hole with a holesaw. Drill though a scrape piece of wood and clamp or nail the board to center the bit.
 

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as a machinist that looks to be a pretty simple job. unless he wants total new ones made, they can just replace the bimetal holesaw on the end. cut the old one off, modify the new one, and reattach.

he may also want to look into a carbide tipped hole saw for a replacement? they should last a LOT longer

any tool & die or machine shop(not engine rebuilding machine shop) should be able to do this.

-Aaron
 

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Discussion Starter #6
as a machinist that looks to be a pretty simple job. unless he wants total new ones made, they can just replace the bimetal holesaw on the end. cut the old one off, modify the new one, and reattach.

he may also want to look into a carbide tipped hole saw for a replacement? they should last a LOT longer

any tool & die or machine shop(not engine rebuilding machine shop) should be able to do this.

-Aaron
If you think you can do this for him for a reasonable fee PM me your contact info and I will forward the info.
 

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lol not me. not my shop. i am just the grunt in the shop. we have done a lot more complicated repairs. any good local shop in my opinion should be able to perform this. it is not much different than stubbing a shaft that has spun a bearing.

-Aaron
 

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Do a search for an increment borer. It is the tool foresters use to age trees, the core sample may be smaller than the one shown in your picture. One forester supply house is called Ben Meadows.
 

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Discussion Starter #9
Do a search for an increment borer. It is the tool foresters use to age trees, the core sample may be smaller than the one shown in your picture. One forester supply house is called Ben Meadows.
I don't believe that these drill bits work on old hard dry wood very well. I am looking for a machine shop that can braze a new cutter onto the existing bits. I believe that the cutters are standard hole saws that have had the back cut off and then are brazed onto the custom shaft.
 

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Well Guess who ended up with this job?

Yup...Me. I just can't say no:laugh:

I did two for Mick the other week, and he liked them so I got the rest from him this past week.

I did indeed use carbide tipped hole saws as 4verticle suggested, and after parting off the threaded piece on the end I turned them to fit inside the tubing.

I got 7 bits made up today on the lathe, still need to braze them.
 

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Yup...Me. I just can't say no:laugh:

I did two for Mick the other week, and he liked them so I got the rest from him this past week.

I did indeed use carbide tipped hole saws as 4verticle suggested, and after parting off the threaded piece on the end I turned them to fit inside the tubing.

I got 7 bits made up today on the lathe, still need to braze them.
Nice job Kenny!!!:good2:
 

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Mick was able to determine that my house was built in 1827 and the first addition was added in 1841. I was hoping the original house went back further, but at least we now know. The land grant goes back to 1685, so the house is not the original.
 

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nice job!

I hope my advice wasn't off with the carbide tipped bits. if he finds a nail it might very well be over with for that bit.

i would think they would have to last longer than the hss bits. and should do the job a lot faster too!

I'm glad somebody local was able to accomplish this for him. I would hate to see something that simple be sourced from over seas.

-Aaron
 

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I finished the job today and took a few video's to show the brazing process.

After cleaning the lathe from the all turning swarf, I covered the ways and carriage with a welding blanket, chucked up the bits in the three-jaw and used an old live center to support the hole saw bit, the bearing in the center was bad anyway so I did not really care about it. I used a paste type brazing flux inside the tube and on the bit itself, a acetylene Turbo-Torch (like a plumber uses) was used for the heat. I set the lathe to turn slow, about 20 RPM or so.






Here is a picture of the seven completed bits after a trip to the belt sander and wire wheel:

IMG_1426.jpg

Here is the little Muvi Pro Camera and the mounting I set up for it:

IMG_1425.jpg
 

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Second Video

 

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Update 3-5-12

Mick has been using the bits, and reported that the carbide tipped saws are working fantastic.


Next job:

He had and extra chuck that the shank had broken off of years ago, so he asked me to repair it or make a new on. I decided just to replace the shank, the rest of it was in perfect shape.

So, I faced off the end where the old shank was and bored a hole .375"x.500" deep, then I turned a new shank 2" long, .500" at the widest and .375" to fit into the bore:
Chuck-1.jpg

Then I brazed the new shank into the chuck body:
Chuck-2.jpg

Then I chucked up the entire piece into a 6-sided 5C collet block and cut three flats .030" deep so the chuck would not slip in the drill. A 3/4" endmill with a .125" radius on the edges was used. I programmed a short CNC routine and just repeated it 2 more times after rotating the collet block in the vice-notice the 2 red hash marks on the collet block so I did not loose track of where I was at:
Chuck-3.jpg

Next I cross-drilled for the spring pin:
Chuck-4.jpg

All completed, ready to reassemble:
Chuck-5.jpg

Finished:
Chuck-6.jpg
 

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nice!
 
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