Endmill or something else for 1 inch hole

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I have a home grown mill machine made out of a broke smithy and a nice 12x12 xy table. I wish to convert it to a single purpose machine to drill flat bottomed 1 inch holes. They only need to be around 1/4 inch deep. The hole will be on the curved section of 4 inch steel round stock.

I don’t think my machine will handle a large endmill. Question is: what cutting tool to use, if this can even be done in my small shop?
 
I would look into using an annular cutter but 1" diameter maybe beyond the limit of a small mill, and they're not cheap.
a boring head may be another option.
I'm sure the more experienced members will show us the way to do it right.
 
I would look into using an annular cutter but 1" diameter maybe beyond the limit of a small mill, and they're not cheap.
a boring head may be another option.
I'm sure the more experienced members will show us the way to do it right.
As far as I know angular cutters are hole saws, meaning they much punch through
 
Drill with a 1" drill, then come back with a 1" 2-flute endmill that has had one flute ground back, making it into a 1" single-flute end mill.

Essentially boring the hole flat and true. You can leave the outside edge flute but take the corner and the end-cutting edge off of one side, the non-center-cutting side.
 
You can sometimes find 1 inch endmills on ebay pretty cheap, since they don't work with normal collet sizes. I made the mistake early on in owning my mill, so I have 6 3-flute ones sitting in a drawer somewhere :/

If you could hold a 1 inch endmill, you could drill the center to depth, then come back with an endmill and clean it up.
 
Drill it to depth with what ever size drill you have , then get yourself a 1" center cutting insert cutter . They have a 1/2" shank .
 
What spindle tapper dose this machine have? Whatever cutter you find you will want to shorten the tool length as much as possible. With the cutter linked below you could make the shortest arbor possible then tap to M12.
Go to tormach Search: 31258
 
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That's the kind of 1" end mill I'm talking about above-but if you're worried about having enough power to cut it cleanly without chatter, knock off one cutting edge-it'll cut slower so you'll wanna drill most of it out, but it will cut cleaner and with less power, and require less rigidity.
 
Yes you're right I forgot you wanted a flat bottom.

I have this 1" end mill and used it often on Aluminum, if you already have the hole drilled to size and depth , maybe you could use it to machine a flat bottom:
https://littlemachineshop.com/products/product_view.php?ProductID=5153
View attachment 280892


Could go with this type of tool, just by itself. Depending on the volume of parts or how costly the project is in different ways could pay to get a nice carbide tool if needed. Or maybe carbide wouldn't be best option. Need forum input on this...

I think your key to doing what you want will be correct feeds and speeds. Some people would chuck that up, turn on the speed to full and drive it in hard only to burn out the tool and mess up the work. But if the speed were set slow like it should (And I would ask questions here about the optimal speed for something that large diameter and in steel - if you have the exact type of steel would help) Also lubricant may or may not be helpful, not always needed for the type of material which is another good question. Get a cheap tachometer for exact speed, it will pay off.

The dedicated one use machine will help too because you can set up a V block and a stock stop to put the part in the right place each time.

And it would be great if these parameters are offered up in this thread to help out and enlighten us all! Best tool, feed, speed.
 
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