Author Topic: Brass Discs  (Read 4575 times)

Offline Mosey

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Brass Discs
« on: August 07, 2013, 03:00:27 PM »
Grandson is making the Elmer boiler and needs to make several brass discs for the floor and roof of the boiler, etc. These are to be about 1-1/4" round x 1/16" thick brass sheet. How shall he cut them out?
Mosey

Online Jasonb

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Re: Brass Discs
« Reply #1 on: August 07, 2013, 03:02:13 PM »
Hacksaw and file.

Or you could make a trepanning tool.

Offline Mosey

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Re: Brass Discs
« Reply #2 on: August 07, 2013, 03:16:25 PM »
and the trepanning tool looks like....? :noidea: :shrug:
Mosey

Online Jasonb

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Re: Brass Discs
« Reply #3 on: August 07, 2013, 03:24:06 PM »
Remove the guide pin if you don't want a hole in the middle of the disc, just clamp the sheet to the mill table on some scrap ply or MDF and feed down slowly.

Online Dan Rowe

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Offline Marinus

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Re: Brass Discs
« Reply #5 on: August 07, 2013, 03:35:50 PM »
My dad made one about 16 years ago and it still works perfectly. It has a HHS bit to cut.
Kind regards

Marinus Kruger

Offline Bearcar1

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Re: Brass Discs
« Reply #6 on: August 07, 2013, 04:25:12 PM »
A boring head with a tool bit that has been carefully ground and honed to razor sharpness, in the mill and using the slowest granny-low backgear should produce the required results. Do not lower the quill, but instead use a steady hand and bring the knee up into the cutter. SLOWLY, about 3-4 thousandths at a time. Use cutting fluid and let the cutter clear itself before advancing again. OR, perhaps it would be better to turn up a wooden blank/plug to size and hammer a couple of copper blanks over it. The blanks would of course require annealing. This method would provide for a flange that would make for a much stronger joint to the boiler barrel when the time comes.


Best of luck


BC1
Jim

Offline Mosey

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Re: Brass Discs
« Reply #7 on: August 07, 2013, 05:46:39 PM »
We are presently working on this in the following manner;
We hot-melt glued a plywood blank to a faceplate,
then, cyanacrylate glued a brass blank to the plywood,
then turned the plate on the lathe using lowest speed and a very sharp HSS grooving cutter.
Success is limited...
The plywood unglues from too much heat, or the plates unglue from too much heat.

Will keep trying, controlling the heat better.
Mosey
                                                                                                                                                                         

Offline mklotz

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Re: Brass Discs
« Reply #8 on: August 07, 2013, 06:02:15 PM »
I have an aluminum sacrificial plate bolted to my faceplate.  OTOH, lots of folks regard faceplates as expendable - a few minute grooves in the faceplate won't seriously impair its future utility.  In fact, they'll probably disappear the next time you take a truing cut across the faceplate.

Hot melt glue is for making flower arrangements.  Degrease everything thoroughly with carburetor cleaner or such and use a good grade of cyano glue.  Gluing directly to the faceplate or a metal sacrificial plate will allow the heat to be dissipated more easily.

Rough cut an octagonal shape with saw/tin snips and then rough to circular shape with belt sander or similar.  Then the only cut you need to make on the lathe is trimming the edge - less heat generated.

or...

An entirely different approach is to clamp the blank to a sacrificial plate on the rotary table and use an endmill to cut the circle.
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Offline dsquire

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Re: Brass Discs
« Reply #9 on: August 07, 2013, 06:08:54 PM »
Mossy

Do as you have been doing and add a small piece of plywood slightly smaller than the required blank. Find the center and use your live center in your tail stock to put pressure against this plywood piece which in turn will put pressure against the brass piece. Another option might be double sided tape which can be easily removed with lacquer thinner. :)

Cheers  :cheers:

Don
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Never let it rest,
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Offline Mosey

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Re: Brass Discs
« Reply #10 on: August 07, 2013, 07:51:52 PM »
Stage 2:
We are successfully making the discs in this manner:
We bolted the disc blank through the plywood backer, which is hot-melt glued to the faceplate. It has a steel washer to spread the load. We are cutting the disc with a wood-working trepanning cutter we have on hand, using very slow spindle speed and delicate use of the spindle lowering lever.
The result is excellent.
Could be improved by making the cutter bit very narrow and honing it's edge.
A great many good methods outlined above by all of you. Thank you all.

(tried the sticky tape, Nitto brand, Japanese, made for machining, doesn't hold)
PS. I believe that some aircraft are assembled using adhesives that are activated by infrared. ( hot-melt type) I don't recall any flower arrangements in the assembly plant, but expect clarification on this.  :facepalm:
Mosey :cartwheel:

Offline mklotz

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Re: Brass Discs
« Reply #11 on: August 07, 2013, 07:57:48 PM »
PS. I believe that some aircraft are assembled using adhesives that are activated by infrared. ( hot-melt type) I don't recall any flower arrangements in the assembly plant, but expect clarification on this.

One question...  Would you fly in a plane held together by the hot-melt glue you're using?
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Offline Bearcar1

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Re: Brass Discs
« Reply #12 on: August 07, 2013, 09:28:55 PM »
Marv, it would depend entirely on if they were serving free drinks with peanuts and if they had the latest new release in-flight movie or not.  :Lol:


BC1
Jim