I'm replacing the Bo-Mar rear sight on my 1911. The elevation screw was a bit funky so I want to chase the threads. I've found that it requires a 6/48 Taper Tap. While I can see the tap on Brownells websight, I have no idea what a Taper Tap is. How is it different from a regular tap, and what tips if any could you offer a novice like myself? (I am pretty handy with tools; gunsmithing is a bit different though)
Taper Tap Tips
- Thread starter YoPedro
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gamachinist
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The "taper" refers to the end of the tap that starts the hole.
There are three common hand tap types:
Taper taps have the first five or six threads mostly removed,and are usually used first to start the threads.
Plug taps have only two or three threads removed (and have less taper to the end of the tap) to allow the threads to reach closer to the bottom of a blind hole.These are the taps most likely to be found in tap and die sets and on hardware and auto parts store shelves.
This tap will probably work fine for chasing out the existing threads.
Bottoming taps have less than one tread removed to allow the tap to thread almost to the bottom of a blind hole.
There are three common hand tap types:
Taper taps have the first five or six threads mostly removed,and are usually used first to start the threads.
Plug taps have only two or three threads removed (and have less taper to the end of the tap) to allow the threads to reach closer to the bottom of a blind hole.These are the taps most likely to be found in tap and die sets and on hardware and auto parts store shelves.
This tap will probably work fine for chasing out the existing threads.
Bottoming taps have less than one tread removed to allow the tap to thread almost to the bottom of a blind hole.
gamachinist said it best.
I will add that you should ALWAYS start a tapped hole with a taper tap.
Trying to start a tap with a plug or bottoming tap especially in small hole diameters such as 6X48 is inviting all the fun that comes with removing a broken tap.
Through holes are started with a taper tap and finished with a plug tap.
Blind holes are started with a taper tap, chased with a plug tap and finished with a bottom tap.
Always use some kind of lubricant on the taps.
I use tap wax because it latches up the chips better than tap oil but oil is better than trying to dry tap in all ways.
I will add that you should ALWAYS start a tapped hole with a taper tap.
Trying to start a tap with a plug or bottoming tap especially in small hole diameters such as 6X48 is inviting all the fun that comes with removing a broken tap.
Through holes are started with a taper tap and finished with a plug tap.
Blind holes are started with a taper tap, chased with a plug tap and finished with a bottom tap.
Always use some kind of lubricant on the taps.
I use tap wax because it latches up the chips better than tap oil but oil is better than trying to dry tap in all ways.
gamachinist
Member
Good point about starting with a taper tap Onmilo.
I didn't have my brain in "gunsmithing" mode.I was thinking about the cast iron and aluminum I usually work with.
I do have three tap sets for everything under 3/8",and some in larger sizes also.
I didn't have my brain in "gunsmithing" mode.I was thinking about the cast iron and aluminum I usually work with.
I do have three tap sets for everything under 3/8",and some in larger sizes also.
If you use a tap holding jig you can start with a plug tap with no probelms.
Either the fancy ones that look like a hand operated drill press, or the simpler ones that sit on a flat surface and align the tap.
Starting taps freehand nearly always results in the frst thread not being complete. (The QA guy will get you.)
Either the fancy ones that look like a hand operated drill press, or the simpler ones that sit on a flat surface and align the tap.
Starting taps freehand nearly always results in the frst thread not being complete. (The QA guy will get you.)
This is a great thread and great advise.
I do in fact use a tap jig for all tapping jobs.
Actually I use three different tap jig/handles depending on the application.
First is my B-Square chuck mounted tap handle that I use on my drill press, this is the set up used for general purpose tapping.
The part must be fixtured to the press table, the spindle lowered to bring the tap to bear, then the tap is hand rotated while bearing down and backing off the spindle using the hand wheel.
Second is a bench mounted jig from Grizzley that I use for shallow hole tapping on flat surface applications.
Third is my Forster drill and tap jig that is used for drilling and tapping holes in receivers and barrels for sight applications. This appliance is excellent and can be used for all types of tapping from shallow small shank blind holes to heavy through holes on any rounded surface.
The Forster jig is used in conjunction with my floor drill press and the B-Square chunck mounted tapping handle.
In all three applications I still use a taper tap first.
Even though the taper tap will not actually tap a four or five thread shallow hole, It will nicely deburr the hole and make alignment and clean cutting of the plug tap a certainty.
These set-ups work well for me and I have only broken maybe five or six taps in 25 years of tapping thousands of holes. HTH
I do in fact use a tap jig for all tapping jobs.
Actually I use three different tap jig/handles depending on the application.
First is my B-Square chuck mounted tap handle that I use on my drill press, this is the set up used for general purpose tapping.
The part must be fixtured to the press table, the spindle lowered to bring the tap to bear, then the tap is hand rotated while bearing down and backing off the spindle using the hand wheel.
Second is a bench mounted jig from Grizzley that I use for shallow hole tapping on flat surface applications.
Third is my Forster drill and tap jig that is used for drilling and tapping holes in receivers and barrels for sight applications. This appliance is excellent and can be used for all types of tapping from shallow small shank blind holes to heavy through holes on any rounded surface.
The Forster jig is used in conjunction with my floor drill press and the B-Square chunck mounted tapping handle.
In all three applications I still use a taper tap first.
Even though the taper tap will not actually tap a four or five thread shallow hole, It will nicely deburr the hole and make alignment and clean cutting of the plug tap a certainty.
These set-ups work well for me and I have only broken maybe five or six taps in 25 years of tapping thousands of holes. HTH
gamachinist
Member
Most of my non gun tapping is done in the drilling machine.Sometimes under power,sometimes by hand in the drill chuck,sometimes guided by a center in the spindle in the center in back of the tap.
All of my gun tapping is done in the machine,so I can make sure it starts true.
Onmilo wrote:
"These set-ups work well for me and I have only broken maybe five or six taps in 25 years of tapping thousands of holes."
I wish I was this good/lucky.
I broke a 10mm tap in an aluminum truck bellhousing a week or so ago.
It was lubbed and must have hit bottom (plug tap in a tap wrench) an twisted off before I knew what happened.Took two hours to remove the tap and helicoil that one hole.
All of my gun tapping is done in the machine,so I can make sure it starts true.
Onmilo wrote:
"These set-ups work well for me and I have only broken maybe five or six taps in 25 years of tapping thousands of holes."
I wish I was this good/lucky.
I broke a 10mm tap in an aluminum truck bellhousing a week or so ago.
It was lubbed and must have hit bottom (plug tap in a tap wrench) an twisted off before I knew what happened.Took two hours to remove the tap and helicoil that one hole.
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