rwillett Posted March 11 Author Share Posted March 11 The stuff below is me thinking aloud and might be complete and utter b0ll0cks. I'm guessing based on what might be common sense and might as well be verified by my dog. That might work BUT everything has to be perfectly aligned across both widths. The E string puts the most load and so that side of the baseplate will have more load. Joining the beams together is hard as you have to drill across four sections accurately and then through the beams to join it to the bottom of the guitar. In principle it sounds great but I think realistically it's a lot more work and I have little confidence in my ability to drill accurately that many holes. I reckon I have circa 0.5mm latitude on each hole. That's pretty tight. Quote Link to comment Share on other sites More sharing options...
SamIAm Posted March 11 Share Posted March 11 Rather than drilling, could you epoxy them together? Sam x Quote Link to comment Share on other sites More sharing options...
tauzero Posted March 11 Share Posted March 11 6 minutes ago, rwillett said: The stuff below is me thinking aloud and might be complete and utter b0ll0cks. I'm guessing based on what might be common sense and might as well be verified by my dog. That might work BUT everything has to be perfectly aligned across both widths. The E string puts the most load and so that side of the baseplate will have more load. Joining the beams together is hard as you have to drill across four sections accurately and then through the beams to join it to the bottom of the guitar. In principle it sounds great but I think realistically it's a lot more work and I have little confidence in my ability to drill accurately that many holes. I reckon I have circa 0.5mm latitude on each hole. That's pretty tight. Sir just needs a pillar drill and a couple of clamps. Or, as m'learned friend suggests, epoxy. Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 11 Author Share Posted March 11 (edited) I 26 minutes ago, SamIAm said: Rather than drilling, could you epoxy them together? Sam x Whilst glue technology appears to have come on in leaps and bounds, my knowledge of it is still stuck (pun intended) to the era when superglue came out, and it was the height of fun to put it on door handles or toilet seats. Yes I was that immature. Epxoy resin might well work very well, or it might not. I'm reluctant to try out yet another technology out that I know nothing at all about. I can manage a 12mm plate (or 2 x 6mm plates), box sections seem to require just as much drilling PLUS connecting together. All other things bneing equal (as I can't prove box section is stronger), I always go for the simpler solution. A pillar drill looks the easiest option and is needed for all the options. Will see if anybody in the village has one first though. Rob Edited March 11 by rwillett 1 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 12 Author Share Posted March 12 A little parcel has just turned up, I may, just may, have over specified the aluminium I didn't quite realise how strong 12mm alumium is. The 6mm appears to be strong enough on it's own. Lets see how this goes. The equal length angle sections were brought to test whether simply adding in two quite thin bits of aluminium to the plywood reduces the flex enough. I suspect not, but lets see. No joy on local pillar drill, so one on order along with some cutting fluid. Rob 4 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 16 Author Share Posted March 16 Pillar drill now here. Plugged in, turned on and tuned in. Might drop out later😊 The clamping mechanism and fence look OK but I'm not jumping up and down with joy and can see a heavy vice looming in my future. Also the laser alignment is out by about 0.3mm on one axis. This might be some sort of record of me dismantling something less than 24 hours after receiving it. No point in sending it back as the next one might be as bad. l 2 Quote Link to comment Share on other sites More sharing options...
Si600 Posted March 16 Share Posted March 16 Laser alignment? You show off. Here's mine, I think they'd invented lasers by then, but they would have been as big as a house. 3 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 16 Author Share Posted March 16 That looks a lot more substantial than mine but also bigger. Not sure the laser makes a massive difference to be honest. We seem to have survived for a few centuries drilling holes without one. Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 16 Author Share Posted March 16 Well so much for maths. My calculations showed that 6mm aluminium should be significantly stronger than 15mm plywood. Rubbish. Just drilled a 6mm slab of alumimium using my nice shiny pillar drill. I made a drill guide to use as everything had to line up perfectly and surprisingly it did. Put everything back together on my test bass and it bends just the same as the 15mm plywood. Approx 2-3mm at each end. Very, very surprised so either I have poor quality aluminium or high quality plywood. Tomorrow is a girls rugby festival in Settle, I'm the organiser so I may not get time to drill the 12mm plate until later in the week. Very disappointed, but more bright paint on the learning curve. Rob 2 Quote Link to comment Share on other sites More sharing options...
SamIAm Posted March 17 Share Posted March 17 20 hours ago, rwillett said: My calculations showed that 6mm aluminium should be significantly stronger than 15mm plywood. Rubbish. I am surprised by this! Not run any maths but from my gut the ally would strike me as stronger and more resistant to bending ... bad gut I guess! Sam x Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 Well I ran the maths and trusted my gut feeling and both were wrong. The 6mm aluminium bent at the same rate as the 15mm plywood. I worked out the aluminium as 9x stronger. Thankfully, I don't do any maths involving safety critical systems. I have an hour free so am drilling the 12mm aluminium and lets see how that works. Rob 1 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 You can see the bend in the 6mm aluminium plate. I'm very surprised as I thought it would be stiffer. The maths says 9x stiffer. That's proven to be a load of b0ll0cks What's interesting is that the printed stuff is holding out under the load. 40% infill seems to be ok. Quote Link to comment Share on other sites More sharing options...
Owen Posted March 17 Share Posted March 17 16 minutes ago, rwillett said: The maths says 9x stiffer. Maths is deeply unreliable. I knew this 50 years ago. Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 Got home after rugby and thought I have to try the 12mm aluminum backbone. I have cutting fluid and used the 6mm as a template. Didn't break the drill but the amount of swarf that comes off, use cutting fluid and it's wet swarf. Need to rethink the tool station. Anyway now have a 12mm backbone that fits, I love precision, and tuned up. There is still a little bow, in the 12mm aluminium. I reckon I must have the crappiest aluminium this side of a Soviet submarine. The bow is small, probably 1mm-2mm across 400mm if that. Massively better than before. I'm not going to 15mm aluminum at the moment. Now the neck is a little flatter, I'll follow the video links that @samiam posted to set it up. Still looks like a scrappy Steinberg, but getting there. Don't stress over some of the heights of things in the picture. Now I have a reasonable backbone I'll make the neck/bridge height the same as my Fender Jazz. This is progress though 1 Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted March 17 Share Posted March 17 Are you sure you are using one of the stiffer alloys of aluminium? Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 4 minutes ago, Owen said: Maths is deeply unreliable. I knew this 50 years ago. You sound like.my youngest daughter. 1 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 1 minute ago, SpondonBassed said: Are you sure you are using one of the stiffer alloys of aluminium? Nope. Not sure at all but so far this week have learnt : 1. Calculating stiffness is pointless unless you really know plywood and or aluminum. 2. Americans need to move to SI units. 3. Plywood is stronger than I knew 4. Aluminium isn't. 5. Pillar drills produce a low of swarf. 6. Pillar drills and cutting fluid produce a vile mixture 1 Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 (edited) 1 hour ago, SpondonBassed said: Are you sure you are using one of the stiffer alloys of aluminium? The bar I have is apparently Grade 6082T6 (Formerly H30TF). I am taking this to mean its Grade 6000 from here https://www.1stchoicemetals.co.uk/aluminium/grades-guide/?doing_wp_cron=1710703985.3204550743103027343750 The higher grades, 7000, appear to be a whole world of cost higher. It apparently is used for defence and aerospace, guitar making doesn't appear to be an option I cannot find a supplier who puts a price up on line. It's all "ring for a price". This tends to mean, if you have to ask the price, you can't afford it. If somebody knows different please tell me. It might mean that I can't even drill the stuff with consumer drills. I used to work at BAE Subs in Barrow In Furness and I would bet a pound to a penny that they have this sort of aluminium all around the workshops. However BAE Subs has armed guards on-prem as it does have nuclear reactors there, so suspect I can't head back up, pop my head around the workshop door, and ask them for a bit. Also I caught e-coli there and almost died, so not particualarly keen to see the old Vickers place again. Rob Edited March 17 by rwillett 2 Quote Link to comment Share on other sites More sharing options...
Richard R Posted March 17 Share Posted March 17 (edited) Aluminium is a commodity metal, so ring for the price might just be the norm as it might suddenly vary wildly. If you have a machine shop or small engineering fabricator nearby they might be able to help. Edited March 17 by Richard R Typo... Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 If I look around me, I see a few farms, a normal garage specialising in Land Rovers and approx 10m sheep. I can't imagine the farmers having any high quality aluminium on hand, they normally reuse and reuse and reuse. Suspect the sheep aren't big users either. I might make a call and check. I might also check out carbon fibre. Quote Link to comment Share on other sites More sharing options...
Jackroadkill Posted March 17 Share Posted March 17 I'm just wondering if it isn't the material that's letting you down here. Instead of a single lengthways aluminium bar, what about four or five stringers that are arranged parallel with the alignment of the neck and "up on edge", so to speak?. There'll be more stiffness and less weight - but it would necessitate redesigning the central part of the bass to accommodate these. Potentially the bridge could be bolted to these, too. Quote Link to comment Share on other sites More sharing options...
Richard R Posted March 17 Share Posted March 17 18 minutes ago, rwillett said: Suspect the sheep aren't big users either. That made me laugh out loud - and then I had to explain to my wife what I was laughing at. Quote Link to comment Share on other sites More sharing options...
tauzero Posted March 17 Share Posted March 17 AIUI, box section is more resistant to bending than plate. Try this: https://www.omnicalculator.com/construction/bending-stress Quote Link to comment Share on other sites More sharing options...
rwillett Posted March 17 Author Share Posted March 17 I have strict limits on the height of components. Total body height is 44mm, pickups are a certain height, other parts of the body have a certain size such as the mounting plate (10-11mm). Everything is a compromise, money, strength, stiffness, complexity, technical issues, weight. If I had unlimited money AND technical ability I'd go carbon fibre. Sadly I don't have either. I'll look at the calc and see if it helps though. Rob 1 Quote Link to comment Share on other sites More sharing options...
Aidan63 Posted March 18 Share Posted March 18 Looking forward to the tone experiments with different material reinforcement strips 🙃 Quote Link to comment Share on other sites More sharing options...
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