Blind Fret Slots - Help Needed

[Anonymous]

Hi

I'm getting to grips with Fusion 360 and to give myself a 'simple project' I am trying to put three fret slots in a piece of wood.

By blind, I mean that the actual slots do not pass all the way across the finger board but stop a short distance from the edges.

I have used a 'Slot' in Sketch as it seemd the right thing but no matter what I do, the slot depth is always the same thickness as the finger board. See attached Top Elevation image, you can see straight through. What I am trying to achieve is a 3mm deep slot in the wood.

I feel I am close but the solution has eluded many (pleasant) hours working on Fusion 360.

A pointer in the right direction would be much appreciated, thanks.

[joel.palioca · Accepted solution]

Hello,

I have attached a quick screencast of what I have done to hopefully show you an example of how I would approach this.  If you are willing to share your model by creating a public link to the model and adding that here so I can look at your model, I can offer some additional advice specific to your model.  You can create a public link by right clicking on the design in your data panel on the left side and invoking the "share public link" command.  I hope this helps you out and as always any questions please ask.

Cheers,

[Anonymous]

Thanks Joel

That's what I am trying to do. I couldn't see exactly where I went wrong and I will need to watch your video a few more times as you're a bit faster than me!

That repeat thing for the slots is cool but do they have to be equal distances apart or can they be moved after creation?

Anyway, I'm going to mark this as an accepted solution but can I get back to you and perhaps share what I have done, as you suggested?

Thanks again...

[amcfarlen]

I used an expression to get the fret spacing in my design. That way I can specify the scale lenght and have the spacing driven by the a formula. It's a very powerful way to build a master model that can be easily updated to your needs. I also use expressions to drive the width, lenght depth and surface radius on my design.

However I found that Fusion struggles with working out spacing after about 15 frets on my computger. I posted about this in another thread.

http://forums.autodesk.com/t5/design-validate-document/extremely-slow-response-when-using-expression...

[joel.palioca]

Of course.  The great thing about our forums is that it is common to see people share their troubles, feedback, and what they are working on.

For the slots, during the pattern command they need to be equal distance apart, but after you complete the operation you can select the geometry and move it to the location you are looking for.  If you just need to do this a couple times, maybe copying and pasting the sketch geometry might be faster for you as well.

Cheers,

[Anonymous]

Hi Allen

Yes, I found that post yesterday evening, and was very impressed with what Fusion 360 can do and with what a great example of the functionality it is. Really powerful stuff, a formula driven design. Thanks so much for such a revealing and interesting post.

I've been a professional software developer all my life, so formula driven systems are familiar ground for me.

But I am new to CAD (and CAM) and it is the actual drawing that is the challenge for me. Albeit, a very enjoyable one...

I build banjos as a hobby and I am guessing we share an interest in musical instrument construction.

I have to say I am super-impressed with Fusion 360.

I have a StepCraft 840 CNC and I cannot wait to get some ideas to materialise...

[amcfarlen]

I've been working on making some blind fret slots, and found that the easiest way for me wasn't to draw and extrude cut them onto the board, but instead just draw lines on a plane. Then project them onto the surface.

All the other methods that I tried either failed to generate tool paths, or the paths were so poor that they were unusable.

When it comes to CAM I use the 2D trace and pick my fret slotting bit as the tool, and the lines to trace. Then use a negative depth to get the fret slot depth that I require. As the bits are very delicate I used a 0.4 max. depth of cut and multiple cuts. Very important to get your feeds and speeds right here.

The beauty of this is that the 2D trace doesn't care what diameter of the bit is. Just that it is following the path. And it follows the contour of the top surface. The tool paths also were spot on

I cut my first fret board using this stratagy yesterday and it turned out a treat. Infact, the best I've ever made.

[Anonymous]

Thanks Allen for the 'head's up'.

I saw the screenshot showing projecting of slots onto radiused fret board surface. Very interesting.

I am assuming the fret slots you are milling are 0.6mm wide. I would imagine a tool that diameter is very fragile. I see you suggest cuts <= 0.4mm but what about feed rates?

I am working towards making a scalloped fretboard, that is, the inter-fret space is a smooth scallop 1 mm deep. I will use 0.8mm Phosphor bronze bar machined in place for the peaks of the scallops. But I have to learn to walk before I can run so, just cutting slots and scallops on separate practice boards is good enough for me at the moment.

Your success with your fret board is an inspiration for me.

Is there any way to PM someone on this forum?

I'd like to see more of what you have done. We are obviously doing something similar...

[amcfarlen]

I'm using a 0.58" double flute cutter.

You can contact me at [email protected]