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This Is So Mechanical...


RestorationAD
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Nice!

What CAD/CAM package are you using?

Also, why make a template for neck fitting for yourself instead of simply cutting the entire body (pockets, outline and all) directly on the machine? Purely a question of (lack of) spindle power with the Colt?

Currently I am using CamBam. It is ok... I am looking into opensource alternatives for 3d mesh work. (like PyCAM)

Right now I am making templates to get used to cutting on the machine.

This allows me to keep working while learning to use the CNC. And it allows me to test the accuracy without hosing really expensive bodies.

I think I should be able to start cutting bodies real soon.

The Colt is plenty strong. 1hp. It has shown no signs of slowing down while cutting. I am pretty sure the MDF is harder on spiral bits than Sapele will be.

One thing that has shown up is run out on the Colt spindle. Apparently it is not as true as some other models. I might move to another spindle that is more accurate if the Colt proves to wobble too much.

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I hear ya. My planned machine is getting an industrial spindle with a VFD, probably 2200 KW. I want something accurate and fast enough for fret slots but powerful enough for everything else - even with routers, handheld, I feel an easy difference between 1.5HP and 3HP machines when making big cuts, and since I want to build acoustic necks as well I'll want to run long (4", 5/8" diameter) ball nose bits. I like overkill a little though. Still dithering on the software end of things - I'll probably end up spending the money on Rhino (can get a student license) and MadCAM, but not entirely sure yet.

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I hear ya. My planned machine is getting an industrial spindle with a VFD, probably 2200 KW. I want something accurate and fast enough for fret slots but powerful enough for everything else - even with routers, handheld, I feel an easy difference between 1.5HP and 3HP machines when making big cuts, and since I want to build acoustic necks as well I'll want to run long (4", 5/8" diameter) ball nose bits. I like overkill a little though. Still dithering on the software end of things - I'll probably end up spending the money on Rhino (can get a student license) and MadCAM, but not entirely sure yet.

That is what I will eventually move to. This machine is to get my feet wet. Hopefully it will pay for a serious machine with an industrial spindle.

I am probably going to add a small CNC mill first though.

ducati?

2006 S2R 1000 Monster. (my 3rd Duc) My old man is building my 75 Moto Guzzi street fighter now.

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I'm very set on buying a small metal milling machine when it is feasible. Whilst I am wanting to make some dovetailed steel/brass infill planes, I would also like to make a few pieces of custom instrument bridges, nuts, etc. from the same materials. Steel hardware with brass saddle witness points and peened brass parts would just look unbelievably cool and unique. Think Karl Holtey planes, but in bass bridge form. :D

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  • 3 weeks later...

Also, you wanted to discuss headstock angles.

I use 12 degrees on all guitars.

Why?

I learned all the angles of neckbuilding from Neal Moser who uses the old school Mexican method of building. His headstock angles are measured in a drop from a distance and not an angle, to start with I followed it blindly until I wanted to know why certain decisions were made.

So after I worked out that this drop was 12 degrees, I then went and did a lot of reading as to how different angles effect string tension and the results, I measured my favorite guitars and they were all twelve degrees and twelve by the data I read on the net just seemed like the perfect average to cover all bases and not run into any trouble.

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  • 4 weeks later...

Body outline. My deck is not perfectly level and I didn't cut all the way through at the back of the body. So we load up some code to do it again. Tabs hold the body but again I missed on the back. I must level the deck properly before next weekend.

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Well the pickup routes are tight and the neck pocket has to be sanded a small amount to make the neck template fit. I was building a tele while the machine was cutting and it is still way faster than I am. I still had 2 hours left to finish the tele.

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Do tell.

I had a bit of drift in the HB routes and I think it is do to pushing a reallyreally long 2 flute 1/4" bit around tight corners.

I am going to try a much more expensive 2 flute end mill first. Next step might be a 3 flute end mill.

My next idea would be a tool change as in switch to a much shorter high quality bit for all the routes and then switch to a longer bit for the body cuts.

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Do tell.

I had a bit of drift in the HB routes and I think it is do to pushing a reallyreally long 2 flute 1/4" bit around tight corners.

I am going to try a much more expensive 2 flute end mill first. Next step might be a 3 flute end mill.

My next idea would be a tool change as in switch to a much shorter high quality bit for all the routes and then switch to a longer bit for the body cuts.

Use a larger endmill and do an offset for rough finish. leave about 0.050 then come back with the endmill you need for the radius and sneak up on the final pass. after you are done then do one more spring pass for final finish.Watch your feeds and speeds as well as the depth per pass.
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+1 on that. When I was doing test work on the Bridgeport I found that pushing it too hard pulled the axes out of whack very easily. Still, reducing feed and/or cut depth and thereby multiplying job time was preferable to consistently inconsistent results. I was frankly very surprised how easily a massive knee mill like that Bridgeport could be pulled out of whack by a simple grabby piece of brass.

I would stick with two flutes, at least from my non-CNC routing experience. Your chip clearance will be a consideration with more than that in which case you are factoring in a new problem.

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Do tell.

I had a bit of drift in the HB routes and I think it is do to pushing a reallyreally long 2 flute 1/4" bit around tight corners.

I am going to try a much more expensive 2 flute end mill first. Next step might be a 3 flute end mill.

My next idea would be a tool change as in switch to a much shorter high quality bit for all the routes and then switch to a longer bit for the body cuts.

Use a larger endmill and do an offset for rough finish. leave about 0.050 then come back with the endmill you need for the radius and sneak up on the final pass. after you are done then do one more spring pass for final finish.Watch your feeds and speeds as well as the depth per pass.

Thanks Mikro!

I can't use a larger end mill until I get a new spindle (probably next year) but I have already started on the roughing vs finish passes. Feeds and speeds are one issue I have to figure out and I fear that trial and error is involved there.

One thing I might try is since I have a flip anyway is going to a shorter end mill and cutting the body partial from each side. That way I don't have to worry as much about flex. A tool change is a pain and I would like to avoid. But I did think about running all the cavities for a batch of bodies then changing the tool and cutting outlines...

Thanks for the advice. I will post the results of the tests.

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+1 on that. When I was doing test work on the Bridgeport I found that pushing it too hard pulled the axes out of whack very easily. Still, reducing feed and/or cut depth and thereby multiplying job time was preferable to consistently inconsistent results. I was frankly very surprised how easily a massive knee mill like that Bridgeport could be pulled out of whack by a simple grabby piece of brass.

I would stick with two flutes, at least from my non-CNC routing experience. Your chip clearance will be a consideration with more than that in which case you are factoring in a new problem.

Chip clearance... I am just getting seriously geeky about this. So you think that a 3 flute might be a bad idea. I am already having trouble not burning up bits...and I am getting some wood burn when the CNC pauses. I am trying to remain accurate so I am currently running 45 ipm with a .125 take. I have thought about slowing the spindle down as I have the stupid thing gagged wide open. I think I can bring it down to 16,000 rpms.

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I've no direct experience (yet, soon!), but I used to see very similar problems with my first router, which could only take small bits. More power and larger bits that don't flex allow the cutting edges to just do their work without introducing additional friction; the finish you get with a 2.5HP router and a 1/2" bit is significantly better than what you can achieve with the same router and a 1/4" straight bit. Upgrading one or both will certainly help quality of cut. It's easier to adjust when you're working handheld, because you can 'feel' when the bit's getting bogged down and back off a little. The CNC can't.

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