What's on YOUR workbench right now?

fretman_2

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Cool on you having the Makita. I've probably had mine for about 4 years now and I was thinking I probably need to replace the brushes. I took them out and very little wear even though I've run the hell out of the thing! So the 0.8KW 's are roughly equivalent. I'll have to check that out.

So 0.1” isn’t too much less than 0.125” (1/8”) and 100ipm is only 20ipm faster than what you’re cutting at, so I would think the tape/glue method would work just fine on my machine. I guess I’ll have to build another tele and find out. :laugh2:

I used to use the same Makita router on my old machine and I loved it. I ran it a bit more conservatively than you run yours because I hated hearing the bearings groan a little bit and my bits were pretty dull. But for the price and the performance, it’s a killer spindle! I found the more expensive air-cooled Chinese 0.8kw spindle to perform almost identically...I was just less worried to run the Chinese spindle for longer jobs, as the Makita would get pretty warm.
 

fretman_2

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Peter...thanks for posting your feeds and speeds. Great info!

My machine is a small commercial model and it tops out at about 240 ipm for cutting and 320 for rapid. The only time I run it at max speed is when I am using a big ball nose bit doing a finish carve. It's taking almost no material. Like the radius on a fret board or the finish carve on an LP top. My surfaces are pretty smooth right off the machine so the step over is very small and DOC shallow as well. It's all about chip load.

View attachment 386462

Here is a snipit of my speeds and feeds from Tools Today bits. I think the fastest is 170 ipm and I usually run around 100 - 120 ipm. Generally the smaller the diameter bit the slower speed and higher rpm. I run my fret slotting bit 0.024" diameter 2 flute end mill at 24 k rpm, my spindle max, at about 40 ipm and my 1/2" endmill at 110 ipm. Tools Today shows speeds for 1x dia depth of cut but has factors for 2x and 3x as well. As I said I am experimenting with deeper DOC to get better life span out of my bits. If you are always cutting only 1/8" deep with a bit that has a 1" or 1 1/2" cutter that's not the best use of the cutter.

Cheers Peter.
 

fretman_2

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Agreed...same guidelines apply to CNC as other power tools!

The reality is, I’m not gonna profile a guitar body at a 1” DOC because you’d need a 10HP spindle to pull that off. You have to take cuts that your spindle can handle, factoring in how rigid the machine is. You also have to balance speed vs. “tool efficiency.” If you cut full depth, but can only cut that deep at 20ipm, what you save in “best use of tool” you lose in speed. I prefer speed when I am using CNC. I can cut plywood at 400ipm and 1/4”DOC, but pulling that off in hard maple just isn’t gonna happen. For me, a 2” cutter is best used to cut through 2” stock. I only care about the length of the tool so I can cut the depths I want/need. My depth per pass is chosen based on what my router can handle and how fast I want to make cuts.

To achieve the correct chipload based on the first tool in that chart (1/2” bit, 2” long, 1/2” depth per pass at 110ipm) would burn up my router! The bits I use are cheaper to replace than the router :laugh2: Plus, the whole conversation here really is about work holding...tape and super glue likely won’t hold down the workpiece if you are making massively deep cuts at relatively high speed.

When the bit costs $20 at Home Depot, tool life isn’t a concern for me. And even more so, with carbide tools, if the chipload is in the ballpark you likely won’t dull the last 1/8” of the tool for quite a long time. Straight cutters work just fine for me. I’d love some nice spiral 1/2” bits but I can’t justify the cost of those, especially when I know I have to sand the finished edge off the machine anyways.

If we’re in a production environment this all changes. Home use CNC can’t exactly play by production CNC rules. Not to mention in a production environment, the power and rigidity of the machine will be massive. The commercial grade machines that fender and Gibson are using take up a footprint larger than my garage.

At the end of the day I kinda view CNC as a fancy router table. Everyone here knows you don’t want to take too deep of a pass with the router. Granted, a CNC will move the router in a more powerful and controlled way, but I still like to apply some of the same guidelines to CNC as I do to other power tools.
 

pshupe

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I think we should start a full thread just for this topic.

In theory I can cut 1 1/2" doc with one pass with a 1/16" step over in the same amount of time and load on the bit as cutting 1/16" doc - 18 times with a full diameter step over. The upside of the first way is I am using the full length of the cutter to cut. This can only be done with CNC and I would say "should" be done. You cannot do this with a router because you cannot control the step over.

The recommended speed is related to the bit not the spindle. I have a friend that is in manufacturing and they test the speeds and feeds and increase until either the bit breaks or there is obvious power problems with either the spindle or the steppers. Then they back it off to find the sweet spot. I have a hand held controller and for the first few times I run a toolpath I hold the controller and can adjust speed and rpm during the cut and make note to adjust the tool path once it's done. Ideally I want to optimize my bit life while cutting with less than maximum load. I use spiral carbide bits mostly and they are around US$100 a piece for the larger diameter ones.

Cheers Peter.
 

fretman_2

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I agree Peter...a new thread. Only problem is that it won't be get a lot of post and would get buried eventually. Any suggestions? Could we get the mods to sticky it?


I think we should start a full thread just for this topic.

In theory I can cut 1 1/2" doc with one pass with a 1/16" step over in the same amount of time and load on the bit as cutting 1/16" doc - 18 times with a full diameter step over. The upside of the first way is I am using the full length of the cutter to cut. This can only be done with CNC and I would say "should" be done. You cannot do this with a router because you cannot control the step over.

The recommended speed is related to the bit not the spindle. I have a friend that is in manufacturing and they test the speeds and feeds and increase until either the bit breaks or there is obvious power problems with either the spindle or the steppers. Then they back it off to find the sweet spot. I have a hand held controller and for the first few times I run a toolpath I hold the controller and can adjust speed and rpm during the cut and make note to adjust the tool path once it's done. Ideally I want to optimize my bit life while cutting with less than maximum load. I use spiral carbide bits mostly and they are around US$100 a piece for the larger diameter ones.

Cheers Peter.
 

fretman_2

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Goodness...$100 per bit. Another issue for me is I use www.partkam.com to generate 2D gcode. It's ultra simple, but it lacks some of the more complex cutting regimes other programs have (like Fusion360). Those more complex cutting regimes could generate gcode that would handle cutting with the full length of the flutes of the bit.

I think we should start a full thread just for this topic.

In theory I can cut 1 1/2" doc with one pass with a 1/16" step over in the same amount of time and load on the bit as cutting 1/16" doc - 18 times with a full diameter step over. The upside of the first way is I am using the full length of the cutter to cut. This can only be done with CNC and I would say "should" be done. You cannot do this with a router because you cannot control the step over.

The recommended speed is related to the bit not the spindle. I have a friend that is in manufacturing and they test the speeds and feeds and increase until either the bit breaks or there is obvious power problems with either the spindle or the steppers. Then they back it off to find the sweet spot. I have a hand held controller and for the first few times I run a toolpath I hold the controller and can adjust speed and rpm during the cut and make note to adjust the tool path once it's done. Ideally I want to optimize my bit life while cutting with less than maximum load. I use spiral carbide bits mostly and they are around US$100 a piece for the larger diameter ones.

Cheers Peter.
 

Tweaker

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The recommended speed does relate to the bit, not spindle...but, if your spindle is only 0.8kw, the spindle simply can’t make a full depth cut at any reasonable speed or stepover. I’ve tried it...it doesn’t work well, unless you want to kill your spindle bearings.

I’m a firm believer that you need a minimum amount of power before you can reasonably accommodate the chipload. I’ve struggled to achieve correct chiploads with that Makita router. If a router struggles to keep up with feedrates with even a 1/8”DOC, correct chiploads are very difficult to achieve.

EDIT: For those who didn't know, Fusion tells you the chipload on the Tool tab when you are creating a toolpath. Fusion calls it Feed Per Tooth, which according to the internet is chipload. I made two...one Adaptive Clearing, and one 2D Pocket. Adaptive clearing utilizes more of the tool, as Peter suggests. 2D Pocket is what I typically use. For both operations, I'm using a 1/2" bit, 15000rpm, and 100ipm. The chipload remains the same on both operations, according to Fusion. When I set Adaptive Clearing to 1/2" DOC and 1/16" stepover, the entire operation for the pocket I am machining (Tele control cavity) takes 5:14. When I set 2D Pocket to 1/8" DOC and .475" stepover, it takes 3:00. Not what I was expecting at all.

What this tells me is, honestly the maching time difference is negligible...so it's probably best to approach which machining style you prefer based on what your machine can handle. I never had good luck with adaptive clearing on my old machine, but my cabinet machine can be pushed way faster and I'll have to experiment with adaptive clearing more.

What I also realize is if you're buying $100+ tools, getting the most life out of them as you can makes the most sense. For me, the tools are disposable and I'd rather replace them every 6 months than replace the router every 6 months, because it's cheaper. But I don't use expensive bits! Also worth noting, when I bid for a cabinet job, I include tooling and purchase new compression bits for the job. So if you're doing work for a client, be sure to include tooling in your bid.
 
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Freddy G

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Just did some work on a cello and a viola. I set the soundposts in both of them and then glued them in place with CA.
Then I set the bridges and tuned them up and glued the bridge feet down to the tops. Stradivarius is turning in his grave :laugh2:
P1070772.jpg
 

Freddy G

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If it's got strings this man ^^^^^ can fix it.
Thanks man!

But you guys are too polite! I thought surely somebody would call me out for gluing the bridges and soundposts into place. :run:

So I'll explain anyway.....these instruments are practical props for a live theatre play I'm doing the sound design for. The play is called "The Lady Killers"....freakin' hilarious! You may have seen the Tom Hanks movie.
Anyway, a practical prop is a term used to describe a prop that actually has to function. So these instruments are played by the actors (albeit extremely badly because in the story they are criminals pretending to be musicians in a string quartet).
Now the problem is they treat the instruments very rough....dragging them up and down stairs, banging them around....so bridges would fall over, soundposts got dislodged. So I thought....I gotta make these more bulletproof...that's why the glue.
 

WhiteEpiLP

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Well I'm no one to talk, one of the first things I did to my hollow body gretsch was to drill through the rosewood bridge block right into the bracing underneath and thread stainless steel rods in making it a fixed bridge.
I'm guessing the main problem with gluing the bridge on a cello or violin would be the lack of intonation adjustment, and some transfer of vibrations.
 

Freddy G

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I'm guessing the main problem with gluing the bridge on a cello or violin would be the lack of intonation adjustment, and some transfer of vibrations.
It's sacrilegious to glue bridges and soundposts on real violin family instruments. That's why I'm sure @DLRG gave me a sad face even after I explained why lol....but these "practical prop" instruments are worth next to nothing and the show is what counts.
 

DLRG

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It's sacrilegious to glue bridges and soundposts on real violin family instruments. That's why I'm sure @DLRG gave me a sad face even after I explained why lol....but these "practical prop" instruments are worth next to nothing and the show is what counts.
You're right there Freddy. The sad faces are for the reason you mention. I take your point re: 'Theatre Props'. However, if an instrument is good enough to find its way on to your bench for sound post, bridge and tuning work. I think that instrument deserves a little more TLC.
 

Freddy G

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You're right there Freddy. The sad faces are for the reason you mention. I take your point re: 'Theatre Props'. However, if an instrument is good enough to find its way on to your bench for sound post, bridge and tuning work. I think that instrument deserves a little more TLC.
I understand the sentiment....believe me I do. It's like cooking a fine steak overly well done (an exaggerated analogy....these instruments are more like hamburger than fine steak :dunno: ) . But I have no choice, the way the actors abuse and bang them around I had to make them more solid. The funny thing is I gave them nice set-ups a couple of weeks ago but that didn't last....bridges and soundposts both knocked out. As far as the theatre is concerned, they only need the instruments to make it through the run of the show, after that they either throw them out or stick them back in the warehouse.

As far as "good enough to find their way onto my bench" well, I'm naturally the guy they turned to being the sound designer, I'm right there.....and they know I'm a luthier so .....
 
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fatdaddypreacher

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therein lies the difference (more than one actually) between you and i. Im a firm believer in heavy duty black cabiniet screws. Its what holds all my necks in place. i generally use 12 or 14. i think a half dozen should have worked on that monstrosity of a violin you did. nice work, chap.
 

ihavenofish

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The reality is, I’m not gonna profile a guitar body at a 1” DOC because you’d need a 10HP spindle to pull that off. You have to take cuts that your spindle can handle, factoring in how rigid the machine is. You also have to balance speed vs. “tool efficiency.” If you cut full depth, but can only cut that deep at 20ipm, what you save in “best use of tool” you lose in speed. I prefer speed when I am using CNC. I can cut plywood at 400ipm and 1/4”DOC, but pulling that off in hard maple just isn’t gonna happen.
A 1" DOC full width profile pass with a 3/8" carbide 2 flute end mill at 18000rpm and 100IPM is pulling 1 to 1.8 hp give or take depending on the wood. Not surprisingly the 1/4" deep cut at 400ipm is the same power. The reason you can't take that cut is usually not going to be because of your spindle power.

Power is rarely the limiting factor on any small machine. It will be a host of other factors on the machine if its a cheaper hobby grade one. Main one being system stiffness. Most machines are too wibbly wobbly to handle that cut. It's putting 30lbs force into the cutter laterally, and spiking much higher than that in resonance.

What's more, your fixturing, and maybe even the wood itself will give up before the spindle.

Machining is not as simple as just "speed' or "power'. You need to approach it intelligently.

Shallow depth of cuts are a waste of a tool. Wood has high mineral and silica content, and wears cutting tools very fast. So cutting with only 1/4" of tool when you need to cut 1" deep is wearing out the tool 4 x faster.

Cutting full width slots like a perimeter is also not great as the high tool engagement creates a lot of heat, wearing the tool even faster and leaving burned areas on the part. You can ruin a shiny new end mill before one guitar body is done - especially in a wood like poplar (never us HSS in poplar, it will be dull in 10-15 seconds).

So, the absolute worst way to cut is shallow full width passes… you know, like everyone does? :)

More cleverness is needed. Borrow some of that intelligence from the metalworking industry, as they have the exact same issues.

Fusion 360 has machining strategies called adaptive clearing for both 2d and 3d roughing. What these let you do is run a helical path down into the full depth of cut, and then take a uniform shallow width of cut through the rest of the operation. You can set the width to whatever your machine can handle. maybe 1mm, maybe 2mm on a 3/8" cutter. maybe you can get away with 5mm, maybe you need to knock it down to 0.5mm. In most cases you should be able to arrive at a cut that is a perfect blend of speed, cutting quality, and tool life.

In woodworking terms, you are operating the cutter like a miniature planer all around it. Like a planer, you also get much better finishes in a shearing operation - with a helical tool. You almost always want to use a carbide helical cutter in wood. Either one meant for wood, or one meant for aluminium (ones for steel aren't as sharp). The ones for aluminium are cheaper - sometimes cheaper than the crappy straight flute hardware store bits. They are also MUCH stiffer. hardware store bits are soft steel. they flex, and even bend while cutting. Carbide will flex very little, letting you use more of your spindles HP and giving you a much cleaner cut.

For me, a 2” cutter is best used to cut through 2” stock. I only care about the length of the tool so I can cut the depths I want/need. My depth per pass is chosen based on what my router can handle and how fast I want to make cuts.
Length of cutter needs to be coupled with diameter. Hobby people tend to buy skinny cutters cause they are cheap. This end poorly though. A 2" straight flute cutter at 1/2" diam as found in hardware stores is meant to cut a shallow finish perimeter ONLY - that's why they have bearing kits. these are wholly not suitable for slotting. They are far too flexy. You'll notice most of the youtube factory videos that show the perimeters being cut are using 3/4 or 1" carbide end mills, or some form of large diameter insert tooling.

I think the main point of what I'm saying here is that tooling choices should not be guesswork, They should be calculated carefully.
 
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marksoundguitars

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This weekend I'm wrapping up a parts-box beater.

I'd found a forgotten Mighty Mite ash body with an experimental finish, so I decided to strip it. Turns out that it had about 5 experimental finishes on it. Took a lot of aircraft stripper to get all the urethane and flake off of it.

The neck is a $30 Chinese special from ebay. Workmanship is good, surprise. Tuners are Chinese Kluson lookalikes from Amazon, also not bad. Chinese pickguard from Amazon, too.

Pickup is a Bootstrap something or other, bridge is a MIM Standard.

Switch is just there to fill the slot--not hooked up to anything. Pots and cap, standard stuff.

Body color is Krylon "lacquer," $4.99 from Ace Hardware. Neck color is a combo of RR Butterscotch and Stew Mac Amber Lacquer. A little selective deconstruction, and it's ready to rock.

Sounds decent, plays decent. With the tone rolled back and the Tubescreamer on I can get some near-LP tones.

I think it could use some stickers. ;)

DoWqpOyl[1].jpg
 
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dcomiskey

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On yet another hockey weekend in MA, I had time to hit a Rockler and Woodcraft and scored a few small gems: two pieces of crotched walnut that I can bookmatch and a sweet black and white ebony board that will make a gorgeous fingerboard!

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fretman_2

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Yea...my stepper motors could probably tear my CNC machine apart. The limiting factor is my spindle...and my Z axis assembly to a lesser degree. I just don't have the extra amps available to my shop to get one of the 1.5KW spindles. Great explanation on the adaptive clearing. The choices for machining in Fusion is mind boggling to me. True...tooling choices should be calculated. That's where I need the most help. I don't want to run a tool test on a good mahogany body, and I don't want to break a bit either.

We need a separate thread for this stuff.


A 1" DOC full width profile pass with a 3/8" carbide 2 flute end mill at 18000rpm and 100IPM is pulling 1 to 1.8 hp give or take depending on the wood. Not surprisingly the 1/4" deep cut at 400ipm is the same power. The reason you can't take that cut is usually not going to be because of your spindle power.

Power is rarely the limiting factor on any small machine. It will be a host of other factors on the machine if its a cheaper hobby grade one. Main one being system stiffness. Most machines are too wibbly wobbly to handle that cut. It's putting 30lbs force into the cutter laterally, and spiking much higher than that in resonance.

What's more, your fixturing, and maybe even the wood itself will give up before the spindle.

Machining is not as simple as just "speed' or "power'. You need to approach it intelligently.

Shallow depth of cuts are a waste of a tool. Wood has high mineral and silica content, and wears cutting tools very fast. So cutting with only 1/4" of tool when you need to cut 1" deep is wearing out the tool 4 x faster.

Cutting full width slots like a perimeter is also not great as the high tool engagement creates a lot of heat, wearing the tool even faster and leaving burned areas on the part. You can ruin a shiny new end mill before one guitar body is done - especially in a wood like poplar (never us HSS in poplar, it will be dull in 10-15 seconds).

So, the absolute worst way to cut is shallow full width passes… you know, like everyone does? :)

More cleverness is needed. Borrow some of that intelligence from the metalworking industry, as they have the exact same issues.

Fusion 360 has machining strategies called adaptive clearing for both 2d and 3d roughing. What these let you do is run a helical path down into the full depth of cut, and then take a uniform shallow width of cut through the rest of the operation. You can set the width to whatever your machine can handle. maybe 1mm, maybe 2mm on a 3/8" cutter. maybe you can get away with 5mm, maybe you need to knock it down to 0.5mm. In most cases you should be able to arrive at a cut that is a perfect blend of speed, cutting quality, and tool life.

In woodworking terms, you are operating the cutter like a miniature planer all around it. Like a planer, you also get much better finishes in a shearing operation - with a helical tool. You almost always want to use a carbide helical cutter in wood. Either one meant for wood, or one meant for aluminium (ones for steel aren't as sharp). The ones for aluminium are cheaper - sometimes cheaper than the crappy straight flute hardware store bits. They are also MUCH stiffer. hardware store bits are soft steel. they flex, and even bend while cutting. Carbide will flex very little, letting you use more of your spindles HP and giving you a much cleaner cut.



Length of cutter needs to be coupled with diameter. Hobby people tend to buy skinny cutters cause they are cheap. This end poorly though. A 2" straight flute cutter at 1/2" diam as found in hardware stores is meant to cut a shallow finish perimeter ONLY - that's why they have bearing kits. these are wholly not suitable for slotting. They are far too flexy. You'll notice most of the youtube factory videos that show the perimeters being cut are using 3/4 or 1" carbide end mills, or some form of large diameter insert tooling.

I think the main point of what I'm saying here is that tooling choices should not be guesswork, They should be calculated carefully.
 




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