Recommend: extra long drill and counter sink bits

[tarbellb]

Looking for a 1 step process to drill a through hole and countersink in METALS but with extra length for clearance reasons

Typically I would use a Center Drill but those are often stubby length

_________________
Anything besides McMaster @$35+ / ea
Countersink Drill Bit for 1/4" Screws https://www.mcmaster.com/product/8914A5

or extra long center drill w 82°
which I haven't been able to find either?

Thanks

 

[Old tool guy]

In stock at home depot

 

[tarbellb]

I have these, they dont play well with steel and harder alloys

Plus the Allen head set screws like to move

 

[Old tool guy]

You didn't mention steel in the op.

 

[tarbellb]

You didn't mention steel in the op.

True. The 2 examples I posted are metal specific but I will edit my post to reflect what I'm looking for

 

[whateg01]

I think you'll have a hard time finding a center drill in anything other than 60. I also don't think you'll find much selection so that mcmaster one might be the best you can do.

 

[Old tool guy]

True. The 2 examples I posted are metal specific but I will edit my post to reflect what I'm looking for

Working with very hard wood, like hard maple, sometimes metal working tools do well. I have used hacksaws to cut tenons, and ******* files for shaping.

 

[CapriMikeC]

Sounds like you want a custom tool for off-the-shelf price?

"Long" drills are often called aircraft drills in catalogs.

There are spotting drills which are different from centerdrills.

 

[AEAdam]

Neither center drills nor spotting drills are technically counter sinks. You probably know this, but some readers may not.

The included angle of a center drill is typically 60 degrees. It’s designed to help center the tail stock taper on a lathe (thus the name). You can buy them in 75 and 90 degrees. US countersinks are typically 82 degrees.

Spotting drills are typically 90 degrees. Metric flush head machine screws are 90, but spotting drills are really not designed to be used as countersink. Their job is to make a “spot” like punch mark to help a drill bit not “walk”, when using a drill press or mill.

To answer the question, I don’t know of a one piece drill countersink for metal, let alone a long drill. I like the zero flute countersinks.

 

[Nutria]

I don't love drill extensions, but that might be helpful for your clearance issues and might also save a bunch of money if this is probably a one-time job.

 

[no704]

 

[OccupantRJ]

Search for 82 degree extra long combined drill and countersink. I know some are 6“ but never looked for 82 degrees in them.

 

[tarbellb]

Interesting- how does the bit stay centered with the set screws coming in from one side

You have a brand of extensions you like ?

 

[PCustoms]

Interesting- how does the bit stay centered with the set screws coming in from one side

You have a brand of extensions you like ?

Centered on what?

That's a countersink, it centers itself on an existing hole...

 

[PCustoms]

I read the OP and thought wood at first, as this:



Looks exactly like a pocket screw drill

 

[Cruzan80]

Centered on what?

That's a countersink, it centers itself on an existing hole...

I think he meant centered on the main shaft (concentric to drill). I am pretty sure the setscrews are only to hold it in, and the bore is sized for the shaft of the countersink.

 

[PCustoms]

I am pretty sure the setscrews are only to hold it in, and the bore is sized for the shaft of the countersink.

Yes.

I've made a few and you can buy them

 

[whateg01]

I think he meant centered on the main shaft (concentric to drill). I am pretty sure the setscrews are only to hold it in, and the bore is sized for the shaft of the countersink.

It really is good enough as is. It doesn't need to be perfectly concentric. Would it be nice, sure. Or maybe that one is made so that it is. Doesn't matter in most applications.

 

[Cruzan80]

Guys, I wasn't saying the version w/set screws isn't good enough. Just the OP asked how it stayed centered, and was clarifying for those who didn't understand what the OP was asking (centered relative to center of drill rotation).

 

[dr_clyde]

The magical term you are looking for is a subland drill.

Once you know the terms for specific tooling it becomes a lot easier to search for.

 

[dr_clyde]

The unfortunate reality of this more specialized tooling is that it's more expensive. Unlikely you will find one for less than $35/40 a pop.

AB Tools will grind you whatever custom tool you want, but be prepared to pay handsomely for it.

 

[tarbellb]

Centered on what?

That's a countersink, it centers itself on an existing hole...

I think he meant centered on the main shaft (concentric to drill). I am pretty sure the setscrews are only to hold it in, and the bore is sized for the shaft of the countersink.

@Cruzan80 understood what I was asking, couldve been more clear I suppose. Even a couple thousands off and it would be a nightmare to run drilling anything hard.

If its bored to the shaft diameter and the set screws are just to keep from spinning, that makes sense. I thought it might have been a more "universal" type extension. Thanks for clarifying

 

[whateg01]

@Cruzan80 understood what I was asking, couldve been more clear I suppose. Even a couple thousands off and it would be a nightmare to run drilling anything hard.

If its bored to the shaft diameter and the set screws are just to keep from spinning, that makes sense. I thought it might have been a more "universal" type extension. Thanks for clarifying

On a standalone countersink, there is very little to keep it from working. It centers itself on the hole. Period. If the whole tool is more rigid, like a chamfering bit, concentricity would be more critical. If the angle of the countersink is critical, then a solid tool should be used.

 

[tarbellb]

The magical term you are looking for is a subland drill.

Once you know the terms for specific tooling it becomes a lot easier to search for.

The unfortunate reality of this more specialized tooling is that it's more expensive. Unlikely you will find one for less than $35/40 a pop.

AB Tools will grind you whatever custom tool you want, but be prepared to pay handsomely for it.

Yes! Once you have the correct term its so much easier

Seems everyone is pretty proud of this particular grind, was hoping to find a no name set that I could limp along until I find what sizes I need most

Thanks Dr

 

[tarbellb]

On a standalone countersink, there is very little to keep it from working. It centers itself on the hole. Period. If the whole tool is more rigid, like a chamfering bit, concentricity would be more critical. If the angle of the countersink is critical, then a solid tool should be used.

Im approaching this from drill press or mill situation, with the tool and workpiece rigid. If the countersink, counterbore, etc... is not spinning concentric to the tool then something will move. Likely ending in a oval/trilobed hole or worse, a broken bit or workpiece.

Nobody wants a wobbling bit, that why i asked for clarity

 

[dscheidt]

Yes! Once you have the correct term its so much easier

Seems everyone is pretty proud of this particular grind, was hoping to find a no name set that I could limp along until I find what sizes I need most

A proper bit of this style is really two independent drills, they don't just grind a small diameter bit at the end. So it's not a trivial shape to grind, and not terribly surprising they're expensive. It's also not the sort of thing people who buy cheap cutting tools will buy, because they'll just use cheap singles for it. The people buying it are doing production, and saving time is worth money to them.

 

[RTM]

The magical term you are looking for is a subland drill.

And now dozens of GJ denizens are searching for them, and, gulping at the prices.

Thanks for sharing the name, a new one on me.

 

[PCustoms]

And now dozens of GJ denizens are searching for them, and, gulping at the prices.

Thanks for sharing the name, a new one on me.

It's new to me too, but I can't envision ever needing one

 

[tarbellb]

ex A- drill and countersink a hole next to the vertical wall of angle iron

keeps your chuck from interfering w the wall

 

[whateg01]

ex A- drill and countersink a hole next to the vertical wall of angle iron

keeps your chuck from interfering w the wall

I do this with a (usually) jobber length drill and an extension like posted above. If I wanted badly enough to do it in one step I would pay to have a combo drill custom ground. I don't though.

 

[PCustoms]

I do this with a (usually) jobber length drill and an extension like posted above. If I wanted badly enough to do it in one step I would pay to have a combo drill custom ground. I don't though.

Yep

 

[whateg01]

I do this with a (usually) jobber length drill and an extension like posted above. If I wanted badly enough to do it in one step I would pay to have a combo drill custom ground. I don't though.

I also want to add that if you are working to a drawing, you do what you have to do. If you are designing your own parts, keep "is this makeable with the tools and processes at my disposal?" In your head.

 

[dr_clyde]

It's new to me too, but I can't envision ever needing one

Cycle times my man.

If you can drill and countersink with a single tool it saves a tool change, a pocket in the magazine and an entire machine operation.

The really dope tools are the ones that can drill, countersink and thread mill a tapped hole with a single tool. I’m working on getting this programmed on my machine currently.

CNC really changed how stuff gets machined, and when you’re making hundreds or thousands of an identical part saving seconds on a cycle adds up to real money.

 

[no704]

Interesting- how does the bit stay centered with the set screws coming in from one side

You have a brand of extensions you like ?

Just whipped that one out of a hunk of stock i had laying around. Its a reamed .2501 so not much slop, it’s almost a press fit.

 

[cannuck]

And now dozens of GJ denizens are searching for them, and, gulping at the prices.

Thanks for sharing the name, a new one on me.

I have a large set of interchangeable pilot countersink and counterbore cutters so no real need for a 2 in 1 tool. So I joined the search crew, but looking where I buy machine tools - and there they were, solid carbide in a range of sizes of 3/16 pilot to over 1/2". Prices went from $250 to over $700.....each. I think I will stick to my ordinary twist drills and a second operation with my whole set of Taiwanese countersinks/bores that cost a bit less than one 3/16 carbide subland combo bit.

 

[PCustoms]

Cycle times my man.

If you can drill and countersink with a single tool it saves a tool change, a pocket in the magazine and an entire machine operation.

The really dope tools are the ones that can drill, countersink and thread mill a tapped hole with a single tool. I’m working on getting this programmed on my machine currently.

CNC really changed how stuff gets machined, and when you’re making hundreds or thousands of an identical part saving seconds on a cycle adds up to real money.

I meant from a home/garage standpoint.

Yes CNC uses all sorts of tooling with very specialized uses.

The guy drilling bedframes in his garage should just move the hole over, not use countersunk screws or use an extension.

 

[whateg01]

I meant from a home/garage standpoint.

Yes CNC uses all sorts of tooling with very specialized uses.

The guy drilling bedframes in his garage should just move the hole over, not use countersunk screws or use an extension.

Because they're cool man!

 

[OccupantRJ]

I have made extended versions of a combined drill and countersink (center drill) when needed by drilling a rod on the lathe with an undersize hole, heating it, then shrink fitting the cutting tool into it. This keeps set screws out of the way during rotation. I needed to fish an electrical cable down an interior wall in the factory that had suspended ceiling. When I drilled through the top plate I found blocking half way down, so made a 4 foot long drill using that method. The building had a high roof deck, so that worked in that situation.

 

[dscheidt]

I meant from a home/garage standpoint.

Yes CNC uses all sorts of tooling with very specialized uses.

The guy drilling bedframes in his garage should just move the hole over, not use countersunk screws or use an extension.

ive countersunk holes with a die grinder. Good access though, just no countersink