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Drill bit? Identity sought


hddennis
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Just purchased a large assortment of antique brass screws that appear to have been from the shop of a woodworker. In the assortments were about 20 of these odd  drill bit like tool bits stamped with the word BULLDOG. They are 1-11/16" long 15/32" OD and 5/16" ID on the back end with a metric internal thread I have yet to identify. 

 

Does anyone recognize them or have any idea of their purpose?

 

Howard Dennis

 

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No a masony drill is used to drill a snug hole in the brick or concrete and the anchor is tapped in. The "teeth" end goes in first and the bolt is then inserted and tightened.  From memory there should be a tapered plug in the  anchor which is pushed down by the bolt and spreads the anchor locking it in the hole. Sometimes called "Loxins".

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8 hours ago, Stude17 said:

No a masony drill is used to drill a snug hole in the brick or concrete and the anchor is tapped in. The "teeth" end goes in first and the bolt is then inserted and tightened.  From memory there should be a tapered plug in the  anchor which is pushed down by the bolt and spreads the anchor locking it in the hole. Sometimes called "Loxins".

Right on sir!  They were part of special anchoring system to hold factory machines in place.  I put several hundred in one summer.  A hammer drill was used with them to get them into the concrete.

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I'm going to disagree somewhat. Working at a coal-fired powerhouse in the 70's we had to put big anchors in a wall to hold up a pipe. The anchors were at least 1" in diameter,had those teeth and were used with a very large hammer drill called a Redhead Gun. The anchors looked like yours but were Redhead Brand. The tapered end on the anchor went into the end of the gun where it friction locked. Then we drilled the hole using the anchor. It was hard to get the hole started exactly where we wanted it but did get it done. When it drilled all the way in,it was pulled out and a tapered pin was put into the tooth end of the anchor and it was pounded into the hole again and nothing was going to pull it out. Then we kicked the drill to the side breaking the top of anchor off at that recessed ring and went off to the next one. I was an apprentice then and had never seen one of those but the journeyman I worked with knew all about them. I guess you could use a regular hammer drill to make a hole but you would still need a tapered pin in the tooth end and be able to pound it in. Then screw your bolt in,not to set the anchor on this type but to hold whatever you wanted to hold up.

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The ones I used fit into an attachment on the drill.  The attachment had a handle sticking out that you rotated clockwise and counterclockwise as the drill pounded on the insert.  This movement helped cut the insert onto the concrete. After the hole was made an insert was placed into the toothed end and the insert was then hammered into the hole when the insert hit the bottom of the hole the force it made spread the toothed end so it would stay in the concrete.  Slow and dusty from what I remember.

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Th

1 hour ago, sagefinds said:

I'm going to disagree somewhat. Working at a coal-fired powerhouse in the 70's we had to put big anchors in a wall to hold up a pipe. The anchors were at least 1" in diameter,had those teeth and were used with a very large hammer drill called a Redhead Gun. The anchors looked like yours but were Redhead Brand. The tapered end on the anchor went into the end of the gun where it friction locked. Then we drilled the hole using the anchor. It was hard to get the hole started exactly where we wanted it but did get it done. When it drilled all the way in,it was pulled out and a tapered pin was put into the tooth end of the anchor and it was pounded into the hole again and nothing was going to pull it out. Then we kicked the drill to the side breaking the top of anchor off at that recessed ring and went off to the next one. I was an apprentice then and had never seen one of those but the journeyman I worked with knew all about them. I guess you could use a regular hammer drill to make a hole but you would still need a tapered pin in the tooth end and be able to pound it in. Then screw your bolt in,not to set the anchor on this type but to hold whatever you wanted to hold up.

 

 

That helps me understand how these get anchored in the wall or floor. I just couldn't figure out what spread the teeth.

 

Howard Dennis

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