round nose endmill

can someone please tell me how to make an efficient roundnose 1.25″ round nose endmill to make the concave cut on the reciever

i tried to make a tool….just made a ball on the end of a bar of freemachining metal….but how do i make i the flutes whates the easiest way of making something that will be able to cut aluminum

i looked on ebay for cheap roundnose endmills…but they are 60-70 bucks and i cant really afford that at the moment….is there some other tool that will be able to make that cut, say some cheap chinese router bit ?


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where did you get that carbide bit ?

I went ahead and purchased a carbide router bit for $20.00.

Using the tools I have (machines), took about 45 seconds to cut the upper and lower tube supports for my .308 project.

It has a half inch shank and I’d guess it will last me a lifetime.

Maybe I should rent it out for shipping costs. 🙂

well the breech riser started out as a very thick walled tube i had laying about…1.25″ OD and about 1″ ID, so i only had to correct the inside curvature to match the outside

i made a cutting tool….or at least tried to

problem is that its not really cutting….i made several passes…and some chips fly….but it seems to be chattering, vibrating, creating alot of heat, and noise rather than cutting….i ended up sanding the part for quite a while to get it to a useable state…not sure the mill will take that kind of abuse

quote Cygnus X:

thanks…7/8ths might do it….3/4 was too small

would a 1″ endmill be better ?

I think that the 1″ would have to be layed over too far. like 55degrees or so.
I see you were making a B50 riser. How did you do it in the end?
looks good for sure.

Try this link it’s full of usefull info!!




thanks…7/8ths might do it….3/4 was too small

would a 1″ endmill be better ?

Cyg, use a 7/8″ endmill and tip your mill head over.
Set over to 44.4 degrees

or a 3/4″ set at 36.9 degrees

test for fit. Works well for shallow depth grooves like on a receiver.



Not all that helpfull but shows it can be done . Its important to make sure theres enough rake from the cutting edge . The size of your cutter makes it tricky ,but we all learn by our mistakes . Im sure ive got a better link just cant find it .

Good forum for machining questions

yeah i did think of useing wood bits…but havent been able to find something that can be used….

most router bits , have that ball bearing…

it would be great if you had a “how to”….

Think ive got a link for making bull nose cutters ……some where on my Labtop , il see if i can find it…… lol . Have you thought of using wood router bits , there cheaper and will cut alloy

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