Drill press hole post? What is this tool?

[lentuk]

First, I am sorry for hijacking you picture runastav.
What do you call the pointed post sitting on the drill press table?
I need to buy or make one of these.

[brokenflint]

Center post drilling jig is what I have called it, not sure of the "official" name.  Easy to make out of threader rod / large washer and a couple of nuts.  Can actually turn the point on your drill if you take it easy.  Also could turn out of stock, I think John Bivins had an article on what he used, have to see if I can find it.   I just made one out of the threaded rod, so far has worked fine for me

Brokenflint

[Acer Saccharum]

That is for drilling holes in pieces at slight angles.

In this photo, the fixture comes to a point, and this point fits in a center punched hole on the opposite side of the lock plate.

There is a lot of the story missing, leading up to how the hole got located on the lock plate in the first place.


Let me try to explain:
With the lock plate in the stock, mark out (or center punch) where you want the bolt to enter the sideplate. Then flip the stock over, and mark where you want the bolt to exit the lock, using a center punch. Now you have an imaginary line from sideplate to lockplate where the bolt will run. But how do you get this hole drilled, especially because it's at a strange angle.

This is where the fixture comes in handy. Set the whole gun, with the lock plate centerpunch mark, onto the point. With a true running pointer in the chuck, bring the chuck down until you get near the sideplate mark. You must shim or brace the stock so it holds steady while you drill. I use the tap drill size, and go right down into the lock plate. I follow with a slightly larger than body drill for bolt clearance.

I would NOT drill that lockplate without providing some wobble prevention, and DEFINITELY provide some stop in case the lock tries to spin on the fixture.

[P.W.Berkuta]

Maybe I'm missing something here but why do you need to use that set-up to drill a through tapped hole for the lock bolt ?
I remove all internal & external lock parts then sand the exterior of the lock plate flat then turn it over and center punch the bolster where I want the lock bolt to go. Place the flat face of the lock plate on the drill press table (a "sacrificial" wood surface is good to use on the table).Then I drill the lock plate for the tap size that I want from the bolster side. I then reinstall the lock into the stock and drill through the stock using the tap drill through hole in the lock plate as a guide. Remove the lock plate and drill the lock bolt clearance hole through the stock. Replace the lock plate and run the tap through the clearance hole in the stock from the side plate side.  It comes out right "on the money" all the time. I also have done blind tapped holes in the bolster but drilling the clearance hole in the stock then requires a special transfer threaded pin to "spot" the hole in the stock.  It takes longer for me to write this than to do it .

[hudson]

I use this drilling a through hole in a stock for a box lock. The pointed tool is mounted in the drill press table, lowered to provide clearance for the stock. Plum bob used to align drill chuck center with center on table. Locate or align the start and ending points for your drilled hole. Repeat as often as necessary with different length drills. Will be necessary to slip longer drills into the partly drilled hole then chuck.

[FlintFan]

That is for drilling holes in pieces at slight angles.

That is exactly right.  This type of set up is a big help if there is any angle at all required in your drilled and tapped hole.  For example like a tang bolt hole, I use it to both drill and countersink and everything stays perfectly aligned.   I should also point out that this fixture is used while all parts are in the stock.  It is used to drill through everything at once. 

Even if everything is "square", while not required, a set up like this greatly simplifies things, and reduces potential errors.  

I made one in a lathe years ago, that simple slips into the center hole of my drill press table.  

[smylee grouch]

Tom, do you think there is an advantage or disadvantage to drilling the hole in the lock while in or out of the gun?

[lentuk]

Removed the "/" from the first "quote" to fix problem. Dennis

That is exactly right.  This type of set up is a big help if there is any angle at all required in your drilled and tapped hole.  For example like a tang bolt hole, I use it to both drill and countersink and everything stays perfectly aligned.   I should also point out that this fixture is used while all parts are in the stock.  It is used to drill through everything at once.  

Even if everything is "square", while not required, a set up like this greatly simplifies things, and reduces potential errors.  

I made one in a lathe years ago, that simple slips into the center hole of my drill press table.  

Is there a certain length post that you recommend?

[T*O*F]

Is there a certain length post that you recommend?

If you make it from threaded rod, you can adjust the length to whatever you require.  Drill and tap the table on your drill for it, and lock it in place with a lock nut.

[greybeard]

I use a 1//2 inch counter sink held firmly in the compound vice on the drill press table.
 Easy to center under the drill bit. Cheap and no labour involved
      Bob

[Bob Roller]

Maybe I'm missing something here but why do you need to use that set-up to drill a through tapped hole for the lock bolt ?
I remove all internal & external lock parts then sand the exterior of the lock plate flat then turn it over and center punch the bolster where I want the lock bolt to go. Place the flat face of the lock plate on the drill press table (a "sacrificial" wood surface is good to use on the table).Then I drill the lock plate for the tap size that I want from the bolster side. I then reinstall the lock into the stock and drill through the stock using the tap drill through hole in the lock plate as a guide. Remove the lock plate and drill the lock bolt clearance hole through the stock. Replace the lock plate and run the tap through the clearance hole in the stock from the side plate side.  It comes out right "on the money" all the time. I also have done blind tapped holes in the bolster but drilling the clearance hole in the stock then requires a special transfer threaded pin to "spot" the hole in the stock.  It takes longer for me to write this than to do it .

On the few I have built,this is also my method.
Drill thru with the tap drill and then REMOVE the lock
plate and drill the clearance hole for the cross bolt.
I use a piece of 2x8 with a 1x2 on the bottom to
create an area to lay the gun on when drilling these holes.
I am assuming the use of a drill press.

Bob Roller

[FlintFan]

Is there a certain length post that you recommend?

The table on my small drill press is about 9 inches square.  The post height on my center is about 2 1/2".  This has given me plenty of clearance for drilling tang bolts.  If you have a larger table, you might need to make your post a bit taller.  

The height is needed because if you think of where the tang bolt hole exits the trigger plate, imagine that as the balance point, that is the highest point and the gun dips down on both sides of that.  Picture in your mind balancing the gun on the point of your finger at that tang bolt hole, both the fore end and butt stock run down hill from there.  If you have a large table on your drill press, and your post isn't tall enough either the fore end or butt stock will bump into the table and prevent you from aligning the drill entry point.  

Hope that makes sense.  
 

[lentuk]

Got it, yes its perfectly clear, thank you.

[Thom]

When I built my first in 94 I upended a 16 oz. plumb bob through the hole in the drill press table. Still works great.

[Keithbatt]

I use a nail clamped in a milling vise on my drill press. Align tip of nail to tip of drill and done.

[Acer Saccharum]

Tom, do you think there is an advantage or disadvantage to drilling the hole in the lock while in or out of the gun?

I drill with lock in stock, so the holes line up. This guarantees the holes are at the same angle. I even start the tap through the stock, into the trigger plate or lock. Then I finish tapping with the parts by hand outside the gun.

[lentuk]

I found this, seems easy enough to make.

"Used to accurately align the holes for drilling lock bolts, tang screws, barrel pins, wrist inlays, ramrod pipes, etc. The main shaft is located and secured onto the table of your drill press in perfect alignment with the drill, allowing for drilling both sides to the middle with perfect accuracy. No more wandering holes or misaligned pins and screws. Complete with instruction sheet."