Author Topic: A neat machining trick---  (Read 444 times)

Offline Brian Rupnow

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A neat machining trick---
« on: November 21, 2017, 04:47:56 PM »
When I designed the hexagon shaped manifolds for my twin steam engine, I wanted them to have "domed" ends, so I designed them that way. Now it's true,--You can do some things on the computer that are almost impossible to do in "real life". The hex rods were drilled out full length to 1/4" inside diameter, then a brass plug silver soldered into each end. I have tried shaping a dome on the end of stock with a file, but was never terribly successful. Then I remembered the 1/2" hand held belt sander that I seldom use. It removes a lot of stock very quickly. I ran the lathe at about 200 rpm and with the running belt sander in hand I shaped the dome "freehand". It went very quickly, and gave excellent results. It worked so well that I considered it worth posting about.---Brian


Online Jo

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Re: A neat machining trick---
« Reply #1 on: November 21, 2017, 04:54:12 PM »
Try turning it with a rounding router bit.

Cuts perfect domes, two tips for about peanuts from China. Free bearing every time  ;)

Jo
Usus est optimum magister

Offline Brian Rupnow

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Re: A neat machining trick---
« Reply #2 on: November 21, 2017, 05:02:56 PM »
Good plan Jo. I've never used a router bit. I guess that would require some type of dedicated holder?

Offline kvom

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Re: A neat machining trick---
« Reply #3 on: November 21, 2017, 05:06:24 PM »
I've used a corner rounding endmill held in a lathe toolholder.

Offline Brian Rupnow

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Re: A neat machining trick---
« Reply #4 on: November 25, 2017, 12:25:17 AM »
Today I got around to trying a rounding over endmill in my lathe to put a radius on the end of a piece of brass stock. It worked like a charm. The only downside to this is that although you can put a nice radius on the stock in the lathe, you can't really do a curved "dome" because you are limited to the radius built into the cutting tool.
« Last Edit: November 25, 2017, 01:06:44 AM by Brian Rupnow »

Offline Stuart

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Re: A neat machining trick---
« Reply #5 on: November 25, 2017, 07:21:35 AM »
Answer

Grind a HSS tool to your required shape ,then you have it for future use 👍👍👍👍👍
My aim is for a accurate part with a good finish

Offline Jasonb

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Re: A neat machining trick---
« Reply #6 on: November 25, 2017, 07:52:35 AM »
What stuart says make a tool to whatever shape you need, Ground Flat Stock is easier to shape




Offline Ian S C

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Re: A neat machining trick---
« Reply #7 on: November 25, 2017, 09:13:55 AM »
If all else fails, grind up a bit of old file, I'v done that, and clamped it on a steel tool holder in the same way you would clamp a Tungsten Carbide tip.
Ian S C

Offline Stuart

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Re: A neat machining trick---
« Reply #8 on: November 25, 2017, 09:15:46 AM »
Yes Jason

I surgested HSS. As I do not know what gear brain has

The way I do it it is to use gauge plate ( flat silver steel / drill rod / w1 ) use a tapered carbide end mill .

Draw up the shape in fusion 360 up side down with the profile required on the bottom , CAM it up with the bottom now the stock top/ model top , have at it in the concert mill , harden/temper to your requirements

The reason to use a tapered EM is to get the clearance all round just tipping it and a normal EM will not do it
But then again with gauge plate you can file up the contours
My aim is for a accurate part with a good finish