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Unertl Style Scope BLock Cut

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Rick H

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#1
I am looking for some help regarding machining a Unertl style scope block. On these types of scope blocks there is a radius type of cut on the right side of the scope block to allow the scope mount screw to tighten into the block. I am trying to find someone that knows where to obtain a cutter for this type of radius cut. I did a search on the forum and came up with nothing. Does anyone know where I may be able to obtain this type of cutter for this operation? I have attached a picture to show the type of cut I am referring to. Thanks for any help.
Rick H. Inkeduntitled_LI.jpg
 

BobSchu

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#2
That looks like a custom made end mill that the manufacturer had made to their specifications. It looks like it has a cupped end. You could have one made, but it may be expensive. You may want to do some calling around to end mill manufacturers to see if they make such a thing.
 

seasicksteve

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#3
You could try PTG or one of the other reamer manufactures. You could probably fashion a single lip style cutter from 0-1 and harden it if you are not trying to alter a hardened base. If you could find an annular cutter that was near the correct size it might be possible to modify it by grinding a radius feature on the internal cutting surface, grinding the relief that will allow the tool to function will be the difficult part
 

derf

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#4
That is an easy cut. I've made many by grinding a 1/4" 2 flute end mill. Grind the end off at about a 45 degree angle so only one flute cuts. I used an old end mill that was damaged on one flute.
 

P. Waller

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#5
The feature can not be produced with a rotary tool from the "top" down as this would create a circular groove in the top surface as well.

Does it look like so
 

derf

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#6
You don't cut it from the top.....you plunge it from the side.
 

682bear

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#7
I would guess that the manufacturers stamp that feature into the blocks instead of cutting it.

-Bear
 

P. Waller

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#8
You don't cut it from the top.....you plunge it from the side.
I understand that, it is difficult to discern from a low resolution photo if the feature has a tapered diameter.
If not a simple form tool as mentioned above would knock out thousands of such parts in a short time, if the OD has a taper it will simply add to the cost of grinding a tool.
 

BobSchu

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#9
Not sure if you guys have seen the windage adjustable rear scope rings made by Leupold, redfield, and a number of other manufacturers, but the bottom of the screw head is radiused and undercut to grip the edge of the scope base to hold the ring in place. This means the screw center is above the base, threaded into the ring side, so the center of this base cut radius would actually be above the top of the base. You would need a cupped end mill cut from the side of the base in the proper radius, which you would probably need one of these scope ring attachment screws to measure- or try to extrapolate from the existing base.
An easier method would be to buy Leupold's gunsmith bases, which are plain blocks with the machining already done except for mounting screws and radius to match the barrel or action. I've used them on a couple rifles and they are really handy. The one you would need for the windage adjustable sight would be a Leupold #50033. I believe the dovetail cut on the sides of this base is for the old Unertl style rings with the clamp bases and the cut shown is to adapt to the Leupold style windage adjustable style rings- but I could be mistaken- it has happened before, just ask my wife.

Bob
 

derf

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#10
You guys are making this grossly complicated........it's a simple plunge cut.
DSC02596.JPG
DSC02598.JPG
Ground from a 1/4" 2 flute end mill. It makes a mating cone to match up with the cupped screw on the scope ring. I've made hundreds of these.
 

bhigdog

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#11
Hand grind a single lip cutter from an old end mill or turn the profile you need using drill rod and mill the "lip" and relief. Harden and sharpen. Simple plunge cut. Likely could be done in a four chuck, a lathe, and a tool bit with the correct profile. Lots of ways to skin this cat at little or no cost..................Bob
 

Rick H

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#12
Mr. Waller: Yes the profile would look like your picture. I never thought of the modified 2 flute cutter, but it certainly looks like it would work. Thank you for all the great ideas gentlemen. Gives me something to go on now.

Rick H.
 
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