Machining a recess in a faced piece question

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dml66
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Machining a recess in a faced piece question

Post by dml66 »

I need to machine a 1" diameter recess, 0.050" deep, into a faced piece of 12L14 LC steel. Another piece, 1" outside diameter, will rest in that recess, ideally with a tight fit. I'd like to be able expand the width of the recess incrementally until a tight fit is achieved.

I don't have any specialty cutters like Trepanning tools, just the basics.

Ideas for best way to proceed?
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rmac
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Re: Machining a recess in a faced piece question

Post by rmac »

dml66 wrote: I don't have any specialty cutters like Trepanning tools, just the basics.
Don't have the cutter you need? Grab a HSS (high speed steel) tool blank and grind one! Here's how:

https://www.youtube.com/watch?v=6PcEBaset1I&t=0s

-- Russell Mac
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Bill Shields
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Re: Machining a recess in a faced piece question

Post by Bill Shields »

Start with an end mill to clear out the center.
Too many things going on to bother listing them.
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GlennW
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Re: Machining a recess in a faced piece question

Post by GlennW »

I ground this one for a quick job. It is ground for tapered sides, but this should give you an idea.

It would benefit from a bit of top rake, but it cut fine for what it was needed for.
DSC04121.JPG
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
dml66
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Re: Machining a recess in a faced piece question

Post by dml66 »

Bill Shields wrote: Fri May 20, 2022 5:41 pm Start with an end mill to clear out the center.
OK, I don't have a mill, but I do have an inherited end mill, 3/8". Lets say I clear out the center, what's next?
hobgobbln
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Re: Machining a recess in a faced piece question

Post by hobgobbln »

If it’s a flat bottom hole across the entire 1” diameter you should just be able to use a facing tool. If you’re cutting a groove, you’ll need one like what Glenn shows.

0.050 isn’t very deep so you’ll probably want a super sharp corner on your cutter. It will wear out fast but may be necessary so your solid bar sits properly. Chamfering the end of the bar that sits that shallow doesn’t give you much room for error for the tight fit you want.

Griz
dml66
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Re: Machining a recess in a faced piece question

Post by dml66 »

hobgobbln wrote: Sat May 21, 2022 11:43 am If it’s a flat bottom hole across the entire 1” diameter you should just be able to use a facing tool. If you’re cutting a groove, you’ll need one like what Glenn shows.

0.050 isn’t very deep so you’ll probably want a super sharp corner on your cutter. It will wear out fast but may be necessary so your solid bar sits properly. Chamfering the end of the bar that sits that shallow doesn’t give you much room for error for the tight fit you want.

Griz
I spent so much time examining the piece to be located on the workpiece, I overlooked the 1/2" hole already center drilled in the workpiece :oops:

So, I think this will be a center-out facing operation. Since the piece to be located will be secured by three screws drilled and tapped in the workpiece, I don't think an absolutely perpendicular outer edge on the recess is needed; it just needs to be tight, and seated flat. If I'm wrong about the inner edge perpendicularity, a boring bar should fix that.
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