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Endmill or something else for 1 inch hole

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Submachine

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#1
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?
 

Ken from ontario

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#2
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.
 

Submachine

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#3
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
 

Wolfram Malukker

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#4
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.
 

ErichKeane

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#5
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.
 

mmcmdl

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#6
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 .
 

Alexander McGilton

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#7
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
 

Ken from ontario

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#8
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Wolfram Malukker

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#9
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.
 

Cadillac STS

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#10
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.
 

AJ

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#11
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.
I`m not questioning your knowledge, I`m a complete newb but I`d like to ask your reasoning behind using the method you suggested. Since the hole depth is only 1/4" why not just use a 1" centering end mill. The point on a 1" drill is almost 1/4". Would`t it be tough to guess the proper depth to stop with the drill ? and why ground off one side of a 2 flute EM ? I think I know the answer you`ll give but I want to make sure I`m close..LOL
 

Submachine

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#12
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 is the purpose of the drilling?
 

Karl_T

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#13
IMHO, your machine is not rigid enough for most the above suggestions. A large endmill is going to want to jump all over on you.

I'd suggest grinding an HSS cutter to go in a boring head after removing most the material with a drill. Use a really low speed and feed by hand with the quill, set quill stop to your depth.
 

T Bredehoft

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#15
Is this what you want to do?
1543428921492.png

I agree that your machine is not heavy enough to do this with one cutter. It could be done with a CNC machine, interpolating the circle with a 3/8 cutter or smaller. I didn't mean to have two images. My bad. 1543428921492.png
 

mmcmdl

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#16
Could you supply us with a little more info as to what your making ? There are lots of different ways to make anything . ;)
 

Submachine

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#17
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.
I do run at slow speeds when cutting steel. I have a home grown v block tie down system that seems to be working well. Basically I am using two brass straps holding the piece down using the t slots. I am going to throw some indicators on it to make sure it is not slipping. The piece itself sits in a v block that runs the length of the piece.

Unfortunately, I purchased the steel from a shop closing up. It machines like mild steel. Once I am through with what I have I will never buy “unknown” steel again.
 

Submachine

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#18
What is the purpose of the drilling?
I am embarrassed to admit what I am building and coming from popular forum where I would get banned or shunned for mentioning the word. Yes, I am building cannons with very nice walnut carriages that I am also making. Not selling, these are to pass onto my children. I was recently forced to leave my profession and go on disability. ( I really regret not buying a mill when I had money -lol). I need to do the most I can without a lot of $$$. I have a Southbend 16 tool room lathe in my basement and this homemade mill.

The trunions have been my nemesis. I plan to mount them 1/4” deep and weld.

Sorry for the rant but I feel I need to justify canon building after being abused on another site. Not bashing the other site, they just don’t want to deal with beginners. :boxed in:
 

Submachine

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#19
So far I think this is the plan, open for shooting holes in it.

Use a small endmill and remove most of the material. Finish with 1 inch endmill.
 

T Bredehoft

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#20
Use a small endmill and remove most of the material. Finish with 1 inch endmill.
Good idea, better, use a series of larger and larger endmills, finishing with 1". You're going to have problems with tool impact as it hits the top of the 4" piece, until it's cutting all the way around. This applies to every size you will use. You might want to use a small, maybe 3/8 4 flute end mill and hand drive it around the circle until you have a flat circle. Several passes, but easier than WHAP WHAP WHAP.
 

mmcmdl

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#21
Just a thought . You really don't need a flat bottom . Why not drill 1/2 hole and turn your shafts to fit and just spot the 1" diameter to be flush ? You are welding it correct ? This is the place to learn , and we're here to help . I'm sure the bashers will be removed or warned on HM . ;):)
 

hman

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#22
Sorry for the rant but I feel I need to justify canon building after being abused on another site. Not bashing the other site, they just don’t want to deal with beginners. :boxed in:
Absolutely no need to apologize.
(1) I recall seeing a couple of other posts/threads about cannon builds. Seems like trunnions are often the issue. So you're definitely NOT out of place.
(2) Lots of newbies here. The only dumb question is the one that isn't asked. I wasn't too far beyond being a newbie when I first joined, and I've learned a whole lot.
(3) This forum is friendly to all! Welcome to the fun.
 

Submachine

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#23
Just a thought . You really don't need a flat bottom . Why not drill 1/2 hole and turn your shafts to fit and just spot the 1" diameter to be flush ? You are welding it correct ? This is the place to learn , and we're here to help . I'm sure the bashers will be removed or warned on HM . ;):)
You will still need to machine space for screwing it in tight, right?
 

mmcmdl

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#24
I wouldn't tap it . Its more of just a locating hole .
 

bhigdog

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#25
Make a fixture to hold your tube and use your 16 inch swing lathe to bore the holes. Either swing the tube or swing the cutter(s). Lots of interesting ways to skin this cat. None of them quick but all doable. Not too much you can't do with a good lathe.........bob
 
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NoobCanuk

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#26
Ok I was just interested in the topic of boring a hole like this. But now reading the project I'd love to see pics as it progresses. Sounds like a cool project and I was always thinking of trying one myself. Just curious what technique you use and how it works out for you.
 

Wolfram Malukker

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#27
I`m not questioning your knowledge, I`m a complete newb but I`d like to ask your reasoning behind using the method you suggested. Since the hole depth is only 1/4" why not just use a 1" centering end mill. The point on a 1" drill is almost 1/4". Would`t it be tough to guess the proper depth to stop with the drill ? and why ground off one side of a 2 flute EM ? I think I know the answer you`ll give but I want to make sure I`m close..LOL
You would spot drill, drill the web size of your 1" drill, then 1" drill to depth. Now that we know the actual purpose, just stop at the 1" drill. This allows a less-than-rigid machine to cut a large hole with the least groaning and grindin' noises.

Since we're dealing with a machine that'll be about as rigid as a well-done spaghetti noodle, and as the original question was how to get a flat-bottomed hole, after drilling to remove as much material as possible with the cheap, easily resharpenable tool, then use the 1" end mill to get the flat bottomed hole. But a 1" end mill will require a LOT more rigidity than the drill bit, as it's not self-centering. Think about using a 1" end mill in a drill press-it isn't likely to come out good. So, we need to lessen the rigidity needed, and the power required to cut, by removing one cutting face-you'd grind the end of the flute back so that only one side of the end mill is cutting-now you've got an accurately sized 1" boring tool without going to the expense of a full boring head, that you couldn't make full use of due to the machine not being up to it.

Also you could use an already broken end mill to do the job and save some cash and a broken tool from the scrap bin.
 

AJ

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You would spot drill, drill the web size of your 1" drill, then 1" drill to depth. Now that we know the actual purpose, just stop at the 1" drill. This allows a less-than-rigid machine to cut a large hole with the least groaning and grindin' noises.

Since we're dealing with a machine that'll be about as rigid as a well-done spaghetti noodle, and as the original question was how to get a flat-bottomed hole, after drilling to remove as much material as possible with the cheap, easily resharpenable tool, then use the 1" end mill to get the flat bottomed hole. But a 1" end mill will require a LOT more rigidity than the drill bit, as it's not self-centering. Think about using a 1" end mill in a drill press-it isn't likely to come out good. So, we need to lessen the rigidity needed, and the power required to cut, by removing one cutting face-you'd grind the end of the flute back so that only one side of the end mill is cutting-now you've got an accurately sized 1" boring tool without going to the expense of a full boring head, that you couldn't make full use of due to the machine not being up to it.

Also you could use an already broken end mill to do the job and save some cash and a broken tool from the scrap bin.
Thanks for explaining that to me. I get it..
 

Ken from ontario

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#29
AJ, I wouldn't look down on your(our) smaller ,less rigid machines, although it is challenging to find the limits of these tools but there are many of us who have managed to work within those limits and enjoy this hobby.
 

Cadillac STS

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#30
Could first complete the outside of the cannon on the lathe. Drill the one inch hole all the way through the cylinder for the trunions. Then with a rod a little little larger diameter than one inch and cut to finish surface place that through the hole with the freeze/heat techinque. Freeze the trunion, heat the barrel and put them together so that the pressure of the joint when back to temp holds them in place with no welding. That way you get a nice clean look on the outside and secure trunions.

Maybe drill the through hole with sequentially larger drill bits then a one inch reamer (Or reamer a little smaller than one inch so the trunion can be from one inch rod for freeze through? Easier to get nice finish than new size on lathe.)

Then back to the lathe to do the bore with the through trunion in place.

Big signal cannons? One inch cup at the barrel base for powder and 2 inch barrel bore?

Pictures would be great!
 
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