rwillett

As part of building the Basschat 8" cab, I needed (wanted?) to rebate some handles into the side. I didn't want the handles sticking out too much so wanted to put a 2mm deep rebate in. I suppose in the old days, highly trained craftsmen would use hammers and super sharp wood chisels and make a wonderful job but would take seven years learning how to do it. I know my limits so I do it the easy way using a 3d printer to make routing templates and routing bushes for a cheap handheld trim router. The basic principle here is that the template protects the area outside of the area to be rebated and provides a simple template that even a muppet novice user with a router can use. The complication is that you have a spinning piece of metal (circa 30K RPM) that cuts the wood, but you don't want it to cut the routing template. That's where the routing bush comes in. A routing bush slots into the router and runs against the edge of the template to ensure that the routing bit doesn't hit the template and trash it. I'm not going to get into the routing bushes, apart from saying I make my own as they are dead simple and I don't want to pay £17 for a set of brass ones that I'll only use one or two of. Many people, myself included, struggled to understand how the routing template is calculated and rather than using maths, I'll demonstrate it using simple diagrams. Step 1 - Get an outline of what you want to cut out. This is the handle # and this is the outline of the handle backplate. I know the corner radius is 10mm as I have a little set of corner radius tools that cost about £3 to buy. I've drawn this in Fusion 360 below. 2. The next step is working out which router bit to use. As the corner radius is 10mm, you could theoretically use a 20mm diameter routing bit, but I tend to use an 8mm for most things as its smaller and easier to manage. So we'll assume an 8mm bit. If you use an 8mm bit, you need a router bush that is a little bigger, so I would use a 12mm router bush with a 1mm thick wall 3. So I can either calculate what to do using a fairly simple formula OR I can draw it out to demonstrate to simplify it. I've drawn an 8mm bit in the middle of the area I want to cut out. Now if I had a really steady hand, I could possibly trace a line to do this, but thats not a good idea, so we have to protect the area to be routed. 4. So I draw a circle to represent a 12mm router bush, thats below. Technically that router bush is 1mm wider than the radius of the router bit. However the 10mm is the inside of the router bush, we are interested in the outside of the router bush which is 12mm, the wall of the router bush is 1mm thick. The outside of the router bush is 2mm, this means that the template for the bush to run against is 2mm wider than the actual area. 5. So we offset the actual size we need to cut by 2mm, that's the red line below. The red line is just Fusion 360 showing the offset and means nothing else We now have the inside of the template done. 6. It's relatively easy now to create the outside of the template, here's a 20mm wide outside. The wider the template, the better it gives the bottom of the trim router something to keep it vertical. I use an acrylic sheet underneath the trim router as it provides a great support for the router and keeps it vertical. I think it was £10 off ebay. I didn't print one because you want to see through it. 7. I add in little 'V's to help placement, I'll draw mounting lines in pencil on the cabinet to align this. 8. If I now extrude this 5mm in Fusion 360 I get this 9. I'll edit this after printing it and showing the template in use.

No problem at all. Be happy to, whens good?

Started on the second cabinet today. This is a dry run fit, so no glueing. So much faster when you have done one before. The panels were all cut a few weeks ago, though I found one end was at an angle. Suspect the circular saw was poorly setup by some idiot. Rather than cutting the batons in advance, I cut them as I needed and used a mitre saw and block rather than a home made table saw. This was a far better way of working and wasn't much slower. Just under two hours to get to this, I do now have frostbite, but well on the way to getting a second cab, so completely worth losing a finger or so, who needs a little finger for playing bass. Front and rear faces are also cut and fit, but I haven't done the holes for the speakers, handles etc yet. Rob

Just looked at the link. Looks good. It reverses the newspaper model of print and distribute to distribute and print. So distribute the files remotely and then print. I tried to set a colour printing business to do this about 30 years ago and we failed to raise the money needed for the business. We did ask for rather a lot... I understand what he's trying to do and he's addressed most of the concerns that were raised to us, things like NDA'S. Would be very interested in seeing the pricing model they use. Perhaps I might put my rates up from free 😁

Dave Let me dig them out and I'll send them down. DM me your address please

Still £6.95 too much.

Never say Basschat is not a source of diverse information 😁 I note we have managed to avoid contentious issues though and nobody has gone passive aggressive.

I also received an offer from him to Buy It Now. I recall it was £600 or so. In a moment of madness, I declined.

I built a CNC machine as a lock down project during Covid. It had a cutting area of 800mmx600mm, it was fun to build and the aim was to design a machine to cut foam for tool drawers, it didn't really do the job I thought it would do, and whilst it was a great learning experience, I have the machine away to the local school to make better use of it. As I was doing anything with bass guitars then, building a bass from wood with a CNC machine wasn't even a thought. If I was going to do anything with a CNC machine, I would go for something decent such as the X-Carve that @Richard R has commented on. I did just check it at https://www.inventables.com/products/x-carve-1 and it appears that the nice entry level kits have been discontinued and they are moving to the X-Carve Pro which are bigger and more money. However there are other kits or systems out there to replace the entry level stuff. I wouldn;t suggest making your own though as I did Rob

I think that's an excellent idea, I look forward to @Richard R showing off his designs and his work on the finished cabinet 😁

I am assuming that the 8" port is not suitable for the 12" cab? My offer to print me still stands but I have no idea of the diameter and length.

Sorry to be obtuse 😁 Fully recognise and agree with your storage and project purchasing approach. The offer is still there though, perhaps I can help at some time. Just let me know. Rob

Brilliant. I recognise the carbon fibre sheet 😁 If there is anything I can help with that needs 3d printing, let me know.

I can't comment on port sizes for a 12" as I haven't a clue 😊 Other people have commented before on the wood and construction method. Your friend seems to want to make things unduly complicated and heavy but I will defer to people who know more about this. Rob