I have a project where I need to mill a bowl into a plate of aluminum. I needs to have a diameter of 3". I have a mill and a boring head and I was thinking of grinding a tool with an arc of 3". Any ideas on how I could do this better?
How to mill a bowl pocket
- Thread starter milotrain
- Start date
Help Support Home Model Engine Machinist Forum:
Lakc
Well-Known Member
I guess a 3" ball nose mill would be out of the question? 
Lakc
Well-Known Member
If it can be done, I am sure Marv has written a program to make it easier. This would probably be a good project for a Volstro, perhaps why they still seem to sell for a pretty penny.
- Joined
- Dec 2, 2008
- Messages
- 971
- Reaction score
- 8
If your lathe will swing it on a face plate, a Bedair type ball turner would get you the profile. I would think twice about trying to make a cut with a surface contact as wide as you need with a profile tool and then I would do it some other way. I can't imagine that you could do that without enormous chatter.
Jerry
Jerry
- Joined
- Oct 20, 2010
- Messages
- 913
- Reaction score
- 132
Mount the work vertical on a Rotab, a boring cutter, at 90° at 1.5"R. Or rotab horz. if its a BP tilt the head XX° (much math required) with a boring head set at 2" radius. I'm looking for the calulations now.
Looking at the drawing again, what you have is a (negative) segment of a sphere, what is the arc radius to be of the bowl, much more than 1.5' as the material is 1" thick with a large hole in the bottom.
To do that the head of the machine would be tilted, and the stock hor. on a rotab. Of course a CNC machine would be the easiest.
Looking at the drawing again, what you have is a (negative) segment of a sphere, what is the arc radius to be of the bowl, much more than 1.5' as the material is 1" thick with a large hole in the bottom.
To do that the head of the machine would be tilted, and the stock hor. on a rotab. Of course a CNC machine would be the easiest.
K
Kermit
Guest
http://www.supertoolinc.com/pop_product_details.asp?id=28603
I'm not sure the link works like it should. It shows a 3 inch diameter 18 tooth milling cutter - 1/4 thick, side cutting with one inch arbor hole.
The three inch diameter would mean(after removing most of the area with conventional methods) you could make repeated cuts and keep rotating the work piece until you have gone a full 180 degrees. You'd still have some sandpapering work to do to remove the ridges it leaves.
I'm not sure the link works like it should. It shows a 3 inch diameter 18 tooth milling cutter - 1/4 thick, side cutting with one inch arbor hole.
The three inch diameter would mean(after removing most of the area with conventional methods) you could make repeated cuts and keep rotating the work piece until you have gone a full 180 degrees. You'd still have some sandpapering work to do to remove the ridges it leaves.
Since you are doing this on a lathe.....
I presume you have a matching (male) part - of find a 3" ball from a ball valve or bearing.
First bore a cone from corner to corner.
Then work out (do the trig.) a series of stepped cylinders in small increments.
Using a radius cutter (radius not really important - say 1/4 to 1/2") remove all the corners of the steps.
Finally "blue" in the ball - remove the high points with the cutter and when you start to get resonable contact go to emery paper.
Of course if its aesthetic rather than functional you won't need to finesse it too much.
Ken
I presume you have a matching (male) part - of find a 3" ball from a ball valve or bearing.
First bore a cone from corner to corner.
Then work out (do the trig.) a series of stepped cylinders in small increments.
Using a radius cutter (radius not really important - say 1/4 to 1/2") remove all the corners of the steps.
Finally "blue" in the ball - remove the high points with the cutter and when you start to get resonable contact go to emery paper.
Of course if its aesthetic rather than functional you won't need to finesse it too much.
Ken
Ken, He ha sno lathe
I think your best bet is the boring head and work out the co-ordinates to cut the curve in steps with a rounded cutter, if you had a rotary tabel it would be easy using the arc function on a DRO but you will have to do teh X feed manually with the cutter rotating not the work
J
I think your best bet is the boring head and work out the co-ordinates to cut the curve in steps with a rounded cutter, if you had a rotary tabel it would be easy using the arc function on a DRO but you will have to do teh X feed manually with the cutter rotating not the work
J
That'll teach me to read the post more carefully before putting my mouth in gear.
You could still do it as a series of cylinders using a boring head - each time you set the diameter down - take a cut - measure and then work out the depth it need to go to - repeat ad nausem - a right PITA but doable.
then finish off by hand and bluing in mating part....
ARRRGGH forget it ! Take to someone with a CNC and pay him !
Ken
You could still do it as a series of cylinders using a boring head - each time you set the diameter down - take a cut - measure and then work out the depth it need to go to - repeat ad nausem - a right PITA but doable.
then finish off by hand and bluing in mating part....
ARRRGGH forget it ! Take to someone with a CNC and pay him !
Ken
Wouldn't it be possible to put it on a rotary table at 45° to the mill table and cut it with a 3" cutter while turning the rotary table? You could probably do it with a simple ball endmill if you can change the angle to the table while keeping things centered correctly. Isn't there a similar apprentice test for making a ball on the mill?
If the diameter of the pocket needs to be exactly 3" a 1/4" wide saw would not work unless it had a full radius tooth profile.
Greg
If the diameter of the pocket needs to be exactly 3" a 1/4" wide saw would not work unless it had a full radius tooth profile.
Greg
Another one who does not read the posts, he has not got a Rotary Table either
J
J
Lakc
Well-Known Member
If you absolutely have to build it, and cant design around it, it sounds like it would be more practical to:
- Invest in tooling
- Farm the job out to somone with a CNC
tel
Well-Known Member
- Joined
- Feb 8, 2008
- Messages
- 3,293
- Reaction score
- 44
Seems to me it would be easiest on a lathe - face plate and large radius cutter. So if you know anyone with a reasonably sized machine I think I'd be begging a favour!
Flipping the drawing over helps as well, I just couldn't get me head around the perspective the way it was. I never was any good at standing on me head!
Flipping the drawing over helps as well, I just couldn't get me head around the perspective the way it was. I never was any good at standing on me head!
