dovetail milling bit for sight installation

[mountainman70]

Hello to all, I would like to know where to get the proper mill bit to cut correct 3/8 sight dovetails. have a new drill press mtd milling vise, and plenty of scrap barrels to practice on.
As always, I appreciate you all. Thanks, Dave 

[Clowdis]

Here are a few: https://www.brownells.com/search/index.htm?k=dovetail+cutter&ksubmit=y  I would hesitate about trying to do this in a drill press type milling machine though. The heads aren't very rigid and the cutters aren't very cheap.

[FlintFan]

One other tip I would mention is to get one of the Brownells cutters that only cuts a .300 width dovetail.  Then move your cutter over on following passes to take it to full size, trying the fit often as you get close.  Use cutting oil, and a slow feed.

I've found many of the available sights have slightly undersized dovetail bases.  If you make a pass with a .375 cutter many sights that are listed to have .375 bases will slide right though.

Better to work up to the correct size. 

And it is still a good idea to have a ground triangular file to put the final finish (i.e. very slight taper) to the dovetail slot. 

Practice on a piece of scrap a couple times before cutting the barrel to work out what offsets you need to bring it to full size.  After a little practice it only takes a minute or two to complete a dovetail slot with a cutter.

[David Rase]

I have bought several item from Pacific Tool and Gauge and have been happy with their products.  http://pacifictoolandgauge.com/120-high-speed-steel-hss-dovetail-cutter-nopix-
When I am cutting a dovetail using a mill I like to use an end mill to remove the bulk of the material and then use the dovetail cutter to finish the job.  Even though I own a mill I find that I can cut a dovetail for a sight or barrel lug just as fast using a hacksaw, caping chisel and file as I can going through the set up on a mill to cut one.  If I do choose to cut a dovetail with my mill, I normally finish it with a file anyway to remove the cutter marks.
David   

[mountainman70]

Thanks for the advise. For all the years I have been building, I have always used the hacksaw, chisel/file method.
However, as my tired ol hands and Arthur,carpal tunnel cause pain, I find I am looking more at mechanization where practical.I like the idea of a .300 cutter and work up.
I will be getting some bits on order presently. Thanks loads guys. Dave 

[T*O*F]

have a new drill press mtd milling vise,

I mill the dovetails on my LR English rifles with a drill press, and also have milled a lock plate out of damascus.  I feed them by hand with the lightest touch on the advance wheel and use lots of lube.  If you feed too fast, it will grab and destroy something in the process.  When I used carbide bits, they ended up breaking.  Since changing to HHS ones I've had no problem.  You won't get chips, but rather a slurry of oil and metal dust.  Get a 6" level and make sure your barrel is level across the flats as well as lengthwise.

[ddoyle]

If you want to mill with less then ideal tooling use a single point Carbon steel cutter. HSS wont get sharp enough. On youtube there is a channel by a guy called clickspring. He has a video on grinding d-bit/single tooth milling cutters.

[Flint62Smoothie]

Just don’t climb mill the cutter if using a smaller diameter one with multiple passes.

[bama]

I am with David on this one. Use an end mill to bulk out the slot then run your dovetail cutter through. This makes the work much easier on the dovetail cutter. I have ruined more than one dovetail cutter trying to cut the hole thing at once.

I also agree with David it is faster for me the cut the dovetails by hand that to get everything set up correctly in the mill to cut the dove tail.

[Bob Roller]

Most of the barrels I have slotted for sights have been 12L14 which can easily
be done in one pass in a rigid milling machine with no wiggle in the slides.
A wood working drill press has no speed slow enough or a base rigid enough
for any accurate milling.I have a vertical mill I bought new 51 years ago this
month and it's still good. I have posted before about using a heavy old Delta/
Rockwell drill press to mill a shallow "V"slot for a fly in a tumbler.I run the tiny
end mill,a .093 stub mill with 3 flutes around 4800RPM which is slow for these
miniature end mills and I am using 1144 Stressproof which is extremely easy
to work with. I wouldn"t think of using a new,sharp end mill of anything bigger
than the .093 and certainly not a new dovetail cutter in any drill press. New mini mills can be had
for about $700 but how rigid they are or if they're any good at all,I don't know.

Bob Roller

[Scota4570]

I agree with Bob. 

I have terrible luck.  If I tried to use a drill press, the chuck would come off, break the milling cutter, spin off the table, fall toward the ground, and cut my big toe. 

 

Drill presses are not milling machines.  A milling machine however, makes a great drill press.  A simple old milling machine is a fine tool to own. 

 

[Bob Roller]

I agree with Bob. 

I have terrible luck.  If I tried to use a drill press, the chuck would come off, break the milling cutter, spin off the table, fall toward the ground, and cut my big toe. 

 

Drill presses are not milling machines.  A milling machine however, makes a great drill press.  A simple old milling machine is a fine tool to own. 

 

My old Delta drill press does has a locking collar on the chuck that keeps
it tight against the spindle taper.It uses a 1 and 1/16"x20 threads per inch
for the collar.
I am simple and old so my mill and I get along well.

Bob Roller

[dogcreek]

I have milled a lot of dovetails, first milling most of the cut with an end mill. But I myself would hesitate to use a dovetail cutter with a drill press.

[ddoyle]

I had a jt33 taper let loose once, the bit and chuck spun like a top on the table. after looking at it for at least a couple seconds like an idiot I reached out to pick it up. second my finger touched it-------zing jumped up bounced off the table ricochet off the colum and spiraled past my face. LOTS of energy even in a tiny chuck once it is doing 3000 rpm.  I still do dumb things but now I wear a full face shield LOL.

[45-110]

drill presses have always looked like a "safe" machine to operate, but there in lies extreme danger. chucks and material coming loose and whirling. they are built for axial loads only....not side loads. i learned the hard way along time ago. now use my bridgeport for almost everything. one of the small mill/drill imports would be the way to go if one continues to purse this hobby. they have been out long enough that a deal could be found used.   safety aside, if you break tooling or mangle your part trying to mill on a d/press the is no economy there.
best
kw

[Bill Raby]

Don't use a drill press for milling. Check Craigslist. Sometimes you will see them for free to the first person that hauls it away.

[Brian Jordan]

Here is a single point tool I use to cut the angle in my dovetails. it is carbide and ground from a worn endmill. the majority of the metal is removed with an endmill first. I do have a real. milling machine and I am able to set up and cut dovetails for both sites in under 30 minutes. drill press spindles are not designed for any side load in a milling situations.
https://photos.app.goo.gl/FlXkLxlLrZFFTTo32

[Bob Roller]

Hello to all, I would like to know where to get the proper mill bit to cut correct 3/8 sight dovetails. have a new drill press mtd milling vise, and plenty of scrap barrels to practice on.
As always, I appreciate you all. Thanks, Dave 

You might have a scrap drill press as well.
Give me a call @304-429-2454.If we are
not home let the answering service kick in
and leave a message.

Bob Roller

[Bob Roller]

I had a jt33 taper let loose once, the bit and chuck spun like a top on the table. after looking at it for at least a couple seconds like an idiot I reached out to pick it up. second my finger touched it-------zing jumped up bounced off the table ricochet off the colum and spiraled past my face. LOTS of energy even in a tiny chuck once it is doing 3000 rpm.  I still do dumb things but now I wear a full face shield LOL.

THAT is the reason for the locking collar style of spindle.
They are identified by threaded area just above the chuck
but I don't know if they are on imported drill presses or not.

Bob Roller

[45-110]

Bob
i have the locking collar on my rockwell drill press......still don't use it for any milling. they still chatter and are hard on expensive cutters. and the cheap imported crossfeed tables put on most drill presses have poor gibs.
kw

[Bob Roller]

As I posted earlier,my old 1964 new Rockwell drill press and the
American made CTandE* table works for the tiny mills I use to
install a fly in a new tumbler. A .078 deep cut sets up no vibration.
I would never try a bigger end mill in any Jacobs type chuck even
in the milling machine.
Bob Roller
* Chicago Tool and Engineering.

[kutter]

Before I had a small milling machine, I would often use a drill press and an end mill cutter to make simple plunge cuts to remove the bulk of the material for a dovetail.  No 'milling' just straight down drilling motion with the endmill cutter.
The depth stop adjusted left me with a clean bottom to the cut and most of the mat'l removed quickly.
Then I squared the sides up with a safe edge file so I didn't ruin the nice flat bottom of the future dovetail. The actual dovetailed sides were then simple chisel strikes to upset the usually soft metal used in the bbls. Same idea for sight dovetails.
Quick to do and w/o any hacksaw work & only a touch of file work.

Now with a mill at hand, I still mill out the bulk of the metal w/an end mill cutter. Then use a dovetail cutter to do the undercut on each end.  Not being a real machinest, I cut one end dovetail to full depth. Then it's cut and try the other till the piece nearly fits.
If it's a sight, I quit at that point and finish by hand w/a safe edge file.
If it's for a bbl pin loop, I can machine those tight enough and I usually soft solder those in place as well.

It's quicker to do it the old way to be truthful about it!

[smallpatch]

I use a .359, 60deg from brownells.  A little touch up with a safe sided file, viola! Perfect dovetails.
I've never seen the need for milling the flat first.