"Fish On" Fretless Bass Project

[Norris]

20 hours ago, mistermikev said:

Would really like to do some sort of fish inlay with multiple different types of inlay material.  Think that would be a fun learning experience. 

Then when it's finished you can sit and practice your scales...

I've already got my coat

[mistermikev]

1 hour ago, Norris said:

Then when it's finished you can sit and practice your scales...

I've already got my coat

I see what you did there you clever devil!  Also... i DO need to practice my scales so... I'm on it!

[mistermikev]

well, learning cam and my head is tired but I hit a sort of milestone this morning on this bass... in terms of getting the initial carve where I want it... still have a long way to go... so many things to learn:

how to tilt my control pockets and neck pocket

what is my plan for how to mount this after one side is carved?  thinking either A) build a form that it can lock into, B ) the edges will still be on the flat plan... at least in two spots so I could just make something to hold the 'other' spot.  C) maybe will have enough material outside my body shape and just need to figure out how to tell the software not to go into those areas and keep them flat

need to do edge treatments

probably 30 other things but I feel a desperation about testing my machine and need to shift focus to a spoilboard and simple test run.

in the mean time... this is what I have so far:

 

at this point I'll appeal to the wealth of cnc/cam knowledge here at projgtr: see any gotchas?  any comments or concerns? 

also, just wanted to say thanks to @curtisa and @MiKro who have sort of mentored me on these initial stages - I really do appreciate your help!!

 

[curtisa]

6 hours ago, mistermikev said:

C) maybe will have enough material outside my body shape and just need to figure out how to tell the software not to go into those areas and keep them flat

Probably this. Treat it a bit like you're making an Airfix kit plane component that is still attached to the sprues. You're creating the body out of a solid slab of timber, so whatever is left behind after doing the full perimeter of the body will still be the full thickness of the thickest part of the body contours and flat. I'd leave the body attached to the outer block using 6-10 tabs and drive some bolts through the blank (outside of the milling area and away from any potential collissions from the cutter) into your spoil board. Mill everything from one side and do the perimeter to half the depth of the body thickness, unbolt it and flip it over and do all the operations on the other side. To 'release' the body from the slab just zip through the remaining tabs on the bandsaw and clean up the leftovers by hand using whatever technique works best for you. If you place your bolt holes at precise locations that are a mirror image of each other you can even flip it over and only have to line it up once, as the body will end up equally aligned whether the front or the back is facing upwards.

 

7 hours ago, mistermikev said:

how to tilt my control pockets and neck pocket

Tilted which way?

[mistermikev]

4 minutes ago, curtisa said:

Probably this. Treat it a bit like you're making an Airfix kit plane component that is still attached to the sprues. You're creating the body out of a solid slab of timber, so whatever is left behind after doing the full perimeter of the body will still be the full thickness of the thickest part of the body contours and flat. I'd leave the body attached to the outer block using 6-10 tabs and drive some bolts through the blank (outside of the milling area and away from any potential collissions from the cutter) into your spoil board. Mill everything from one side and do the perimeter to half the depth of the body thickness, unbolt it and flip it over and do all the operations on the other side. To 'release' the body from the slab just zip through the remaining tabs on the bandsaw and clean up the leftovers by hand using whatever technique works best for you. If you place your bolt holes at precise locations that are a mirror image of each other you can even flip it over and only have to line it up once, as the body will end up equally aligned whether the front or the back is facing upwards.

 

Tilted which way?

where are my manors - thank you so much for the response!!

 

no idea what airfix and sprues are (you sure this is english?) hehe.  all sounds right on about the body... trick being how to tell the software to stop the contour pass before it hits those areas.  doing a two rail sweep so I would think it would know but in the 3d preview it seems to cut into that area. 

great tip on the bolts... unfortunately the center of this design (assuming I keep the tightest 'canvas' around it) is offset... which I fear my complicate that but it is a fantastic idea and one I'll have to try on a test run. 

I guess my starting point on the machine is going to be the anchor(center) in aspire?  so once I send g code to the machine I guess I have to somehow guide mach3 to the starting point... and then start it?  that whole part is still muddy to me.

tilted - well... the neck pocket is going to get a 1 degree break/tilt to compensate for the bridge.  the control and battery cavities might need to tilt down as the approach the middle of the body in order to give me the required 1" of clearance for the batteries and 1.25" clearance for push pull pots (that will be tight).

[curtisa]

29 minutes ago, mistermikev said:

great tip on the bolts... unfortunately the center of this design (assuming I keep the tightest 'canvas' around it) is offset... which I fear my complicate that but it is a fantastic idea and one I'll have to try on a test run. 

You'd still get two bolts on the centreline - one in front of the neck pocket and one underneath the tail. You could probably sneak two either side of the waist as well that would sit on a straight line perpendicular to the centre. That'd get your bolt locations on a mirror-able cruciform shape.

 

32 minutes ago, mistermikev said:

I guess my starting point on the machine is going to be the anchor(center) in aspire?  so once I send g code to the machine I guess I have to somehow guide mach3 to the starting point... and then start it?  that whole part is still muddy to me.

Your starting point can be wherever you like, as long as the cutter will move within the intended confines of your blank, hit everything it should and miss everything it shouldn't. If you've nominated the centre of the model to be the centre of the block of wood (say +Y takes you towards the neck, -Y towards the bridge, +X to the bass side, -X to the treble, +Z upwards away from the face of the guitar, -Z plunging into the body), you'd guide the cutter to that point in Mach3, zero all your axes and hit the 'go' button.

The only caveat I'd suggest being aware of is that any operation you need to do that involves removing and repositioning the work needs to allow for your starting point to be repeatable. If you do something that deletes your starting point (say, cutting your pickup cavity removes any pencil mark you place to be the reference point of the milling operation) you're going to have a hard time trying to line it up again to do any further cuts. That also goes for flipping the body over to mill the front and back, which was why I suggested adding drill holes at known locations.

 

46 minutes ago, mistermikev said:

tilted - well... the neck pocket is going to get a 1 degree break/tilt to compensate for the bridge.  the control and battery cavities might need to tilt down as the approach the middle of the body in order to give me the required 1" of clearance for the batteries and 1.25" clearance for push pull pots (that will be tight).

Tricky. Your only solution to those scenarios may be to place the body on something that has the tilt built in to it just for those one or two operations.

[mistermikev]

27 minutes ago, curtisa said:

You'd still get two bolts on the centreline - one in front of the neck pocket and one underneath the tail. You could probably sneak two either side of the waist as well that would sit on a straight line perpendicular to the centre. That'd get your bolt locations on a mirror-able cruciform shape.

 

Your starting point can be wherever you like, as long as the cutter will move within the intended confines of your blank, hit everything it should and miss everything it shouldn't. If you've nominated the centre of the model to be the centre of the block of wood (say +Y takes you towards the neck, -Y towards the bridge, +X to the bass side, -X to the treble, +Z upwards away from the face of the guitar, -Z plunging into the body), you'd guide the cutter to that point in Mach3, zero all your axes and hit the 'go' button.

The only caveat I'd suggest being aware of is that any operation you need to do that involves removing and repositioning the work needs to allow for your starting point to be repeatable. If you do something that deletes your starting point (say, cutting your pickup cavity removes any pencil mark you place to be the reference point of the milling operation) you're going to have a hard time trying to line it up again to do any further cuts. That also goes for flipping the body over to mill the front and back, which was why I suggested adding drill holes at known locations.

 

Tricky. Your only solution to those scenarios may be to place the body on something that has the tilt built in to it just for those one or two operations.

good point re centerline... just would have to keep them equidistance on the y axis.

ok, had my axis messed up I guess cause was thinking x is but to neck but I suppose it could be anything.  thank you for the info on the center - that clears up a lot. 

"known locations" so if you give it it's starting point on the face... then flip it using those posts... you don't have to tell it center on the back, right?  you can just hit go again?

tricky - well... I'm going to attempt to cross that bridge via software.  I'm told it is tricky... but a two rail sweep is the mechanism by which you accomplish in my cad... so will have to explore that some more.  soooo much to learn!

again, very much appreciate the tutelage.

[curtisa]

27 minutes ago, mistermikev said:

"known locations" so if you give it it's starting point on the face... then flip it using those posts... you don't have to tell it center on the back, right?  you can just hit go again?

Correct. Provided you do it all in one sitting and don't allow the PC or CNC to go through any form of reset, potentially you only need to zero once.

 

28 minutes ago, mistermikev said:

tricky - well... I'm going to attempt to cross that bridge via software.  I'm told it is tricky... but a two rail sweep is the mechanism by which you accomplish in my cad

The trouble with machining a pocket like that, if you leave the body mounted flat on the bed, is that the back wall of the pocket leans forward and overhangs the bottom corner where it meets the floor of the cavity. It's physically impossible to mill a 89 degree wall with a cutter that can only be held at 90 degrees.

While it is possible to machine the floor of the neck pocket with a software-introduced 1 degree fall, the final finish won't be perfect as the end of the cutter, being at a less than perpendicular angle, will leave little 'half moon' divots as it travels around. The base of the cavity will only be an approximation of the true flat surface you've modeled.

The only way around it is to either tilt the cutter (which is impossible with your machine), tilt the workpiece or somehow disguise the gap that will be introduced at the top of the cavity and live/deal with the poor surface finish on the bottom face of the cavity.

[mistermikev]

Just now, curtisa said:

Correct. Provided you do it all in one sitting and don't allow the PC or CNC to go through any form of reset, potentially you only need to zero once.

 

The trouble with machining a pocket like that, if you leave the body mounted flat on the bed, is that the back wall of the pocket leans forward and overhangs the bottom corner where it meets the floor of the cavity. It's physically impossible to mill a 89 degree wall with a cutter that can only be held at 90 degrees.

While it is possible to machine the floor of the neck pocket with a software-introduced 1 degree fall, the final finish won't be perfect as the end of the cutter, being at a less than perpendicular angle, will leave little 'half moon' divots as it travels around. The base of the cavity will only be an approximation of the true flat surface you've modeled.

The only way around it is to either tilt the cutter (which is impossible with your machine), tilt the workpiece or somehow disguise the gap that will be introduced at the top of the cavity and live/deal with the poor surface finish on the bottom face of the cavity.

good info there... well... what I was hoping for is a tilted floor... but 90 deg walls.  perhaps for the ctrl cavities I can accomplish something close by doing multiple overlapping slices of progressively deeper pocket... because it won't much matter to the controls if the floor is perfectly flat.  I just need the extra room.  the cover pocket can be flat but the control cavity uneven.

all good info - thank you for your input.

[Andyjr1515]

Great info, @curtisa and very interesting project, @mistermikev  .  I'm firmly a spectator on this one, but it's a fascinating show!

[mistermikev]

5 hours ago, Andyjr1515 said:

Great info, @curtisa and very interesting project, @mistermikev  .  I'm firmly a spectator on this one, but it's a fascinating show!

well thank you fer sayin' so!!  having a ball myself!

[mistermikev]

so... channeling the spirit of carl thompson this weekend as I practice resawing and planing pieces for my bass. 

I have oscillated back and forth about doing a glueup of 4 pieces of purpleheart + top or and more 'pieced together' thingy in the spirit of carl thompson.  you can see my orig blank top left here and my 2nd one front ctr below.  purpleheart is so heavy that I'm thinking I might try to work in more lams of maple for my wings of the body.  I guess I can always use one as a lab rat and choose what one I like most towards the end.

no resaw expert... but I'm learning... made a great big planing jig out of 2x4... works fantastic.

my floor is starting to look like some sort of psychadelic purple snow christmas... might hold a rave here next weekend idk!

getting more familiar with the cnc too... did up a spoil board complete with training wheels... and a dust collection boot.

[mistermikev]

starting to be able to visualize it. We're looking at the back of the bass here.  the opposite side will get either a flamed maple slip match top, or a figured oak slip matched top.  Haven't decided which one to go with. 

couple notes: to self

1) building a big heavy 2x4 planer sled makes for solid rigidity going through the planer as well as a very soar back.

2) the upper horn there... going to require some forethought to have that come out w/o the tip being part of the centerpiece wood there.  I want that detail to be part of the wing... so after I glue these side wings up I'm going to have to take a strong 1/4" cut on the table saw up to the start of the horn... then stop the saw (mercy me - a very serious proposition as it is a doable cut but one that should def be taken seriously). 

This middle piece had to be that wide so that the lower (left) body would fit within the lovely piece of purpleheart I wanted to use.  This means the upper right horn would go into the centerpiece territory. 

3) my tablesaw is only 10" which means I have just uner 3" of blade height to work with.  The neck blank is just over 3.  I'm doing a scarf joint on this neck with a multilam headstock that will be a sandwich similar to the body wings.  So... I can do that scarf with:

A) the tablesaw (not enough blade height)

B )  my headstock angle router jig (might be too lean of an angle) 

C) the cnc (I'm not confident this will leave the kind of flat finish I want)

[curtisa]

Good call on the dust boost for the CNC. I can't live without mine. Right up there with a LED light ring underneath the spindle to illuminate the cutting area.

 

5 hours ago, mistermikev said:

The neck blank is just over 3.  I'm doing a scarf joint on this neck with a multilam headstock that will be a sandwich similar to the body wings

I vote for option D - rough it in on the bandsaw (or even hand saw it) and finesse it by hand using a plane and/or sanding block. If your headstock angle jig isn't the right tool for that particular neck and your tablesaw only able to cut it under borderline conditions, it's going to take you longer to CAD up a fancy one-off model, work out the toolpaths and machine it on the CNC. Pick your fights.

[mistermikev]

6 hours ago, curtisa said:

Good call on the dust boost for the CNC. I can't live without mine. Right up there with a LED light ring underneath the spindle to illuminate the cutting area.

 

I vote for option D - rough it in on the bandsaw (or even hand saw it) and finesse it by hand using a plane and/or sanding block. If your headstock angle jig isn't the right tool for that particular neck and your tablesaw only able to cut it under borderline conditions, it's going to take you longer to CAD up a fancy one-off model, work out the toolpaths and machine it on the CNC. Pick your fights.

hehe, was already thinking I should build one and put some leds in it.  was going to run them to a motherboard battery. 

option d you say... well sir, I don't have a hand plane but I do have a beltsander and/or my rigid oscillating sander has the sort of belt sander attachment... that might work quite well for this.  thanks for the suggestion. 

pick your battles - tru dat.  that said... you work it out one time and it will be there for you in the future.  guess I'm just itching to do some real work w it!

[MiKro]

So as far as the tilted pocket you will need to make a jig that places the surface at the correct angle for the body to lay on. As far as Sprues. in your tool path settings go to advanced options in the profile tool path and choose tabs. set these accordingly, then calculate. These will hold the body to the outer piece of cutoff wood so it remains as one piece.

[MiKro]

As far as the center is not the best option for X0, Y0  you should use a corner that is referenced from your X0 Y0 machine coordinates.

Does the machine have the ability to home? If so, then home the machine. set everything to zero. Go in to mach 3 choose offsets and and then choose G55 or G56 just not G54 then jog or use MDI to move to a specific location , Let's say X2, y2 for an example. once done. then rezero those. That is now a work coordinate using g55 or what ever you chose.  Make sure to save the settings.

Now you have the ability to always find work offset place from the machine coordinates. when you run a part for it you will select G55 or what ever you chose before running anything. YOU can always edit the Gcode to reflect using that as well if you want. I change mine constantly over a period of time as my locator pins may become sloppy. but it is still a referenced work offset from machine coordinates.

MK

[mistermikev]

Just now, MiKro said:

So as far as the tilted pocket you will need to make a jig that places the surface at the correct angle for the body to lay on. As far as Sprues. in your tool path settings go to advanced options in the profile tool path and choose tabs. set these accordingly, then calculate. These will hold the body to the outer piece of cutoff wood so it remains as one piece.

right on.  certainly good advice there.  I have become familiar with the tabs - it's a very nice feature - just wish that had an easier toggle-on/off for it.

I've seen that you can do a 2 rail sweep or a tilt at the component level that will give one the appropriate angle... any issue with using those?  I ask because it's common to see folks recommend tilting the work piece as opposed to using this and I wondered why - something I'm missing?  I used the 2 rail sweep method for my 1 deg neck pocket.  I do see the down side of the butt edge remaining 90 deg (not 89 deg) but in my case that part will be covered by my neck overhang anyway.  I could make the neck stock an extra 2mm long and back bevel it to fit the 91 degrees. 

i see amana tool makes a 3 degree bit... will keep looking for 1 degree and 4.5 degree but not holding my breath!!

[MiKro]

See here.

 

[mistermikev]

Just now, MiKro said:

As far as the center is not the best option for X0, Y0  you should use a corner that is referenced from your X0 Y0 machine coordinates.

Does the machine have the ability to home? If so, then home the machine. set everything to zero. Go in to mach 3 choose offsets and and then choose G55 or G56 just not G54 then jog or use MDI to move to a specific location , Let's say X2, y2 for an example. once done. then rezero those. That is now a work coordinate using g55 or what ever you chose.  Make sure to save the settings.

Now you have the ability to always find work offset place from the machine coordinates. when you run a part for it you will select G55 or what ever you chose before running anything. YOU can always edit the Gcode to reflect using that as well if you want. I change mine constantly over a period of time as my locator pins may become sloppy. but it is still a referenced work offset from machine coordinates.

MK

this is a subject that has really caused me some grief.  the machine has no mechanical zero stop mechanisms ie no home per se.  I've seen a bunch of threads where folks have added them... but I'm not there yet. 

I have taken the machine to lower left corner and max y and set that as home... but then I am unable to utilize the soft stops.  Using machine coords and trying to alter the soft stops... it just does not seem to respect them.  I know this must be an issue with my brain... PEBKAC error/operator error... but had chased it around one day and then just got beaten into submission. 

the machine itself seems to be setup to have a center zero... because using machine coords none of the corners are actual zero.  I need to dig into that xml file and figure out where those settings are but just too lazy to install an xml viewer on my pc as I'm about to build a new one anyway. 

for now... my kludge is that I built in some center lines on my spoil board.  if I toss a 15deg engrave bit in there I can get the center dialed in pretty well... but yeah - it's a pita and not the best way to do it.

[MiKro]

Do not use soft stops as they move with your zeros and cause problems .

Edit the XML with notepad if nothing else

 

 

[MiKro]

what is the controller that is being used? Picture of the boards would help adding limit switches at least for just homing should be realitively easy.

 

[mistermikev]

6 minutes ago, MiKro said:

Do not use soft stops as they move with your zeros and cause problems .

Edit the XML with notepad if nothing else

 

 

right on... I will take the advice, but find a free xml editor and edit it.

I haven't opened mine up yet, but I believe it should be this one:

https://www.ebay.com/i/224181412357?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=224181412357&targetid=935083617267&device=c&mktype=pla&googleloc=9032152&poi=&campaignid=10897367470&mkgroupid=108153776780&rlsatarget=pla-935083617267&abcId=9300403&merchantid=101708222&gclid=Cj0KCQjwufn8BRCwARIsAKzP697QKf966av-r8hGnaFu7gGH-3pqFiqlA5_Gv8LaD6aV0sF-E_Hbt38aAp87EALw_wcB

It at least uses the bobcnc driver. 

[mistermikev]

meanwhile... out in the garage... gluing up panels... then realize I put one of the long boards on the short one (glue is dry now) while I was applying glue to the long one... so bunch of swear words... wet rag to get the glue off... I'm guessing my 1/4" flamed maple piece is going to look like a ski when it dries.

old smell... such is life.  will get some more practive milling down new longer puple heart piece today!!

[mistermikev]

 

lots of room for improvement, but I cut the carve on my prototype body today... the finish pass for some reason went 1/4" deeper than I expected despite not changing my z... so will have to revisit the design on that.  The edges are going to need some massage in a few areas... will have to make my cut areas bigger in my design to fix that.  Learned a lot... can probably still turn this into something nice with a little work and glad I didn't learn all that on my purpleheart!!