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Help figuring out how to machine this.

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HellawellCustoms

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#1
Hey guys new to machining here and just got my first mill a few months ago. Took a few months to gather all the tooling for it. Anyways I'm not sure if I'm over thinking this or what. But I bought the mill to make folding knives. I got a rotary table and a coaxial indicator and I built a sort of jig to hold the metal. My one problem is I am wondering how to center the template to the hole accurately.

Not sure if I am explaining it properly but my plan was to use my dro to drill the 3 holes and then slot the track. If I do it withought the template I'm unsure how to line the template up to the holes to make the profile of the cut on my band saw if that makes sense. I attached pics to explain it
 

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T Bredehoft

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#2
Put the template on the blank. punch ctr of the three holes. put the blank in the fixture , with zero x y set. put the center hole on zero, clamp. drill center hole, move in Y until you're over the top (as you look at it) hole. drill this hole. Crank the table around until the third hole is in place to be drilled. drill 3rd hole. Pur a tiny two flute end mill in the collet, (lower the head as needed and CLAMP it. lower the end mill until it enters the hole about .015. snug the clamp on the rotary table and slowly crank it around until it meets the second hole. lower the tool another .015 and crank it back to the 3rd hole. Repeat until done. In steel, run to tool between 1000 and 1500, where it sounds, feels good. Depending on the size of your endmill and the target width of the slot, you will want to make finish passes.
 

JimDawson

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#3
Maybe make a sheet metal template, then align the holes in the templet with the holes in the part. Then scribe around the templet to get the cutting lines for use on the bandsaw.
 

Richard King 2

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Are the 2 small holes centered on the big hole or o---O---o ? but on an angle to the blade? Do you have another blade you are copying or is this #1? I have an idea, but would like a bit more info.
 

francist

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#5
It's quite possible I'm not grasping the problem, but when I do stuff like that I glue the paper template to the blank, drill and machine the critical holes, then saw to the template outline last. Spray mount (3M Super 77) or rubber cement, depending on how tenacious you want it to adhere.

-frank
 

P. Waller

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#6
Is this the first operation?
 

MSD0

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It's quite possible I'm not grasping the problem, but when I do stuff like that I glue the paper template to the blank, drill and machine the critical holes, then saw to the template outline last. Spray mount (3M Super 77) or rubber cement, depending on how tenacious you want it to adhere.

-frank
I’ve even used a regular glue stick before.
 

Silverbullet

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#8
Sounds like T has given your easiest way to do it. Only way I do them is dykem and scribed lines and punch marks. But I'm old school. If your planning on making many copies I'd make up a drilling jig to clamp to the steel so it's reproduced on each blade. A jig even for your milling can be made up. Your operations aren't real complicated.
 

HellawellCustoms

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A little update on my progress. I drilled/reamed and slotted the 3 holes no problem! Turned out great and much more accurate with the DRO. Now my only real problem is figuring out how to trace the profile accurately. so that i can cut the profile of the blade out. I was thinking of somehow getting an acrylic template made and I could pin it and clamp the acrylic piece and then trace but I'm not sure where to find a place that would cut me a blank like this.
37674303_10155823108591314_1551327880779137024_n.jpg
 

T Bredehoft

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#10
Without CNC you're not going to be happy with anything you can accomplish. Sorry!
 

Asm109

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#11
If you can make a dxf file of your profile, any company with a laser cutter or water jet can make you a template.
 

JimDawson

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#12
I was thinking of somehow getting an acrylic template made and I could pin it and clamp the acrylic piece and then trace but I'm not sure where to find a place that would cut me a blank like this.
Why can you not make the shape you want by hand tools and grinding? I would use a piece of sheet metal. This is the old school method of making templates, pre-CNC. ;)
 

HellawellCustoms

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#13
Why can you not make the shape you want by hand tools and grinding? I would use a piece of sheet metal. This is the old school method of making templates, pre-CNC. ;)
Being a folder, there are some strict tolerances, so I am aiming to be as accurate as possible.
 

JimDawson

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#14
Being a folder, there are some strict tolerances, so I am aiming to be as accurate as possible.
I see. How do you plan on cutting out the blade profile once you have the template and have scribed the profile to the work piece?

Do you have a CAD file for the blade?
 

HellawellCustoms

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#15
I see. How do you plan on cutting out the blade profile once you have the template and have scribed the profile to the work piece?

Do you have a CAD file for the blade?
Band saw and a 2X72 Belt Grinder. I do have a CAD file of the blade.
 

JimDawson

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#16
That's what I was hoping to hear. :) So if you can make the actual blade with the band saw and belt grinder, you can make a template the same way. A file and some Emery cloth would be helpful also.

Since you have a CAD file for the blade, as @Asm109 said, somebody locally with some kind of CNC equipment could make the template for you. Almost anything would work; router, mill, laser, water jet, maybe even a 3D printer.
 
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