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How do you drill concentric holes of different diameters on a drill press?
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I have this need a lot.
Often times I need to drill maybe a 1/4" hole, all the way through the piece, and then a 3/8" or 1/2" hole half way through the piece in the same spot. It is often imperative that these holes are exactly concentric.
With a smaller drill press, you cannot just keep the workpiece clamped in place because to remove the smaller bit and replace it with a larger bit (or vice-verse) will end up breaking the alignment and it's nearly impossible to get it back again (within a few thousandths of an inch) by eye.
Are there special drill bits or guides for this purpose?
drilling drill-bits
asked 21 hours ago
AgmLauncher
1211
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up vote
4
down vote
favorite
I have this need a lot.
Often times I need to drill maybe a 1/4" hole, all the way through the piece, and then a 3/8" or 1/2" hole half way through the piece in the same spot. It is often imperative that these holes are exactly concentric.
With a smaller drill press, you cannot just keep the workpiece clamped in place because to remove the smaller bit and replace it with a larger bit (or vice-verse) will end up breaking the alignment and it's nearly impossible to get it back again (within a few thousandths of an inch) by eye.
Are there special drill bits or guides for this purpose?
drilling drill-bits
asked 21 hours ago
AgmLauncher
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago
add a comment |
up vote
4
down vote
favorite
up vote
4
down vote
favorite
I have this need a lot.
Often times I need to drill maybe a 1/4" hole, all the way through the piece, and then a 3/8" or 1/2" hole half way through the piece in the same spot. It is often imperative that these holes are exactly concentric.
With a smaller drill press, you cannot just keep the workpiece clamped in place because to remove the smaller bit and replace it with a larger bit (or vice-verse) will end up breaking the alignment and it's nearly impossible to get it back again (within a few thousandths of an inch) by eye.
Are there special drill bits or guides for this purpose?
drilling drill-bits
asked 21 hours ago
AgmLauncher
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I have this need a lot.
Often times I need to drill maybe a 1/4" hole, all the way through the piece, and then a 3/8" or 1/2" hole half way through the piece in the same spot. It is often imperative that these holes are exactly concentric.
With a smaller drill press, you cannot just keep the workpiece clamped in place because to remove the smaller bit and replace it with a larger bit (or vice-verse) will end up breaking the alignment and it's nearly impossible to get it back again (within a few thousandths of an inch) by eye.
Are there special drill bits or guides for this purpose?
drilling drill-bits
drilling drill-bits
asked 21 hours ago
AgmLauncher
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 21 hours ago
AgmLauncher
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 21 hours ago
AgmLauncher
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 21 hours ago
AgmLauncher
1211
asked 21 hours ago
AgmLauncher
1211
1211
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
AgmLauncher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago
add a comment |
The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago
The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago
add a comment |
2 Answers
2
active
oldest
votes
up vote
5
down vote
Forstner bits have a small point on the end which leaves a slight indentation in the wood in the center of the hole. Use this to align your drill bits after changing them. But, to do this, you'll have to drill them the opposite way you're thinking - drill the biggest (but shallowest) hole first, followed by the next smallest / deepest. This keeps that slight indentation from the point on the drill bit present in the wood, allowing you to align the next drill bit.
answered 20 hours ago
mmathis
1,972530
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
add a comment |
up vote
0
down vote
You can drill the smaller through-hole first, then use a counterbore tool. The end of the counterbore will use the through-hole as a guide and will cut a flat-bottomed hole of a larger size exactly centered on the smaller hole.
answered 16 hours ago
MTA
101
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MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
Forstner bits have a small point on the end which leaves a slight indentation in the wood in the center of the hole. Use this to align your drill bits after changing them. But, to do this, you'll have to drill them the opposite way you're thinking - drill the biggest (but shallowest) hole first, followed by the next smallest / deepest. This keeps that slight indentation from the point on the drill bit present in the wood, allowing you to align the next drill bit.
answered 20 hours ago
mmathis
1,972530
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
add a comment |
up vote
5
down vote
Forstner bits have a small point on the end which leaves a slight indentation in the wood in the center of the hole. Use this to align your drill bits after changing them. But, to do this, you'll have to drill them the opposite way you're thinking - drill the biggest (but shallowest) hole first, followed by the next smallest / deepest. This keeps that slight indentation from the point on the drill bit present in the wood, allowing you to align the next drill bit.
answered 20 hours ago
mmathis
1,972530
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
add a comment |
up vote
5
down vote
up vote
5
down vote
Forstner bits have a small point on the end which leaves a slight indentation in the wood in the center of the hole. Use this to align your drill bits after changing them. But, to do this, you'll have to drill them the opposite way you're thinking - drill the biggest (but shallowest) hole first, followed by the next smallest / deepest. This keeps that slight indentation from the point on the drill bit present in the wood, allowing you to align the next drill bit.
answered 20 hours ago
mmathis
1,972530
Forstner bits have a small point on the end which leaves a slight indentation in the wood in the center of the hole. Use this to align your drill bits after changing them. But, to do this, you'll have to drill them the opposite way you're thinking - drill the biggest (but shallowest) hole first, followed by the next smallest / deepest. This keeps that slight indentation from the point on the drill bit present in the wood, allowing you to align the next drill bit.
answered 20 hours ago
mmathis
1,972530
answered 20 hours ago
mmathis
1,972530
answered 20 hours ago
mmathis
1,972530
answered 20 hours ago
mmathis
1,972530
1,972530
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
add a comment |
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
I've found this does not work with softwood, or plywood because it's very easy for the point of the forster acting as a probe to alter the existing point in the shallower hole. And because the point of the forstner is not conical (but rather, a two-edge blade), it can be quite easy for the alignment to be off by a few thousands of an inch. This can have an adverse effect on the precision of say, a threaded insert or a bushing, often resulting in binding of the screw. Generally the point of a forster is NOT a reliable register for exact concentricity.
– AgmLauncher
18 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
@AgmLauncher For what it's worth Even though the tip of the Forstner is not conical, the divot that it produces is conical.
– Ast Pace
2 hours ago
add a comment |
up vote
0
down vote
You can drill the smaller through-hole first, then use a counterbore tool. The end of the counterbore will use the through-hole as a guide and will cut a flat-bottomed hole of a larger size exactly centered on the smaller hole.
answered 16 hours ago
MTA
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
You can drill the smaller through-hole first, then use a counterbore tool. The end of the counterbore will use the through-hole as a guide and will cut a flat-bottomed hole of a larger size exactly centered on the smaller hole.
answered 16 hours ago
MTA
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
up vote
0
down vote
You can drill the smaller through-hole first, then use a counterbore tool. The end of the counterbore will use the through-hole as a guide and will cut a flat-bottomed hole of a larger size exactly centered on the smaller hole.
answered 16 hours ago
MTA
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
You can drill the smaller through-hole first, then use a counterbore tool. The end of the counterbore will use the through-hole as a guide and will cut a flat-bottomed hole of a larger size exactly centered on the smaller hole.
answered 16 hours ago
MTA
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 16 hours ago
MTA
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 16 hours ago
MTA
101
answered 16 hours ago
MTA
101
101
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
MTA is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
AgmLauncher is a new contributor. Be nice, and check out our Code of Conduct.
AgmLauncher is a new contributor. Be nice, and check out our Code of Conduct.
AgmLauncher is a new contributor. Be nice, and check out our Code of Conduct.
AgmLauncher is a new contributor. Be nice, and check out our Code of Conduct.
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The woodworking guides suggest this is actually very simple, you are supposed to be able to replace a smaller bit with one or more larger bits without moving the workpiece and breaking alignment. But this ability obviously depends on the design of the drill press and on the length of some or all of the bits being used and how they relate to the workpiece height. Now that said, saying you need a bigger drill press isn't really a viable answer! And there are other means to ensure you get near-perfect concentricity no matter which hole you drill first BUT....
– Graphus
12 hours ago
......you're asking too much of the material to achieve accuracy within a few thousandths of an inch every time. Especially with softer woods, especially including most common softwoods, the wood itself just won't allow this (even with the best equipment in the world). Accuracy in the range of a couple hundredths is all you can realistically expect sometimes, because wood is inherently variable (and occasionally contrary) stuff!
– Graphus
12 hours ago