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curtisa last won the day on November 10

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About curtisa

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  1. Four new rockers are coming to life

    That, to me, looks like a classic case of feeding the workpiece into the rotating cutter such that you're routing 'uphill' against the grain of the timber. There are ways of strategically changing direction when routing that will minimise (if not eliminate) this from happening so that you only route 'downhill', but you do need to work with cutters that have bearings on top and bottom. I made a brief write-up about this topic a while back. You may find it useful for future reference:
  2. Crate GT-100H Tube Biasing

    I reckon you'd be better off asking your question over at a forum such as this one. Biasing a 4x EL34 amp is likely to be pretty trivial provided you have the right equipment, take the correct safety precautions and accept the risks of working on your own amp. If anyone can show you how it's done, you'll have better luck over at the Music Electronics Forum.
  3. Any interest in a guitar specific CNC design?

    As long as you've identified them, it's a good start. Down here at least, 5mm and 10mm 'things' can generally be found that can substitute as spacers - aluminium flat bars and acrylic plastic sheets can be had in those sizes.
  4. Operation Shoestring

    Bridge looks to be made of copper, or at least a copper-plated non-ferrous alloy of some kind.
  5. Any interest in a guitar specific CNC design?

    I'm using MGN15 knockoffs on mine, but I'm also using the smaller 3030 metric profile extrusions. There's plenty of meat on the smaller extrusions for the 15mm rail to sit on. Although, how well the 3030 extrusions will work over a much longer frame such as yours may need some re-thinking. Quality of the rails and bearings seems decent. I had one carriage out of 12 that felt quite 'crunchy' when under load though. I initially thought I'd have to order a replacement until I decided to disassemble it and found it just had some fine steel shavings stuck in the ball race channels. While that doesn't really point to fantastic quality control on the part of the manufacturer, provided you don't mind pulling things apart it was completely salvageable without having to make a claim with the seller or order more parts. You get what you pay for. Despite what many people think of the Chinese auctions, the sellers who have been in the game for any length of time do actually want to help you if things aren't what you expect. 9 times out of 10 they will attempt to rectify things if you approach them reasonably with a fault in one of your purchases. It does look big. You sure you want to make it big enough for the worst case, or just big enough to cover most reasonable situations I will say that if you want to make it bolt-together firendly, also consider how each component can fit together without resorting to odd sized spacers and shims. The combined height of the rails/bearing blocks vs the X axis leadscrew mounting brackets are one example.
  6. Amps for setups

    What about testing with a modelling amp or PC with VST amps installed? Different pickups will work with different styles of music, so why not cater to those styles by having as many amps at your disposal at minimal cost?
  7. Any interest in a guitar specific CNC design?

    Given the limitations of the building materials and budget, I reckon you'll be fine running the rails as you have shown it in your pic. I'd continue on with the design as you have it. The intent is to mill timber, not titanium. And a 600mm wide gantry made from MDF and a bit of Al isn't going to weigh dozens of kilos. The way you have the rails on the sides also gives you the option of replacing them with Hiwins later on with minimal work to the frame, as they're perfectly capable of being mounted in that configuration too. Probably all you'd need to do is make up some spacer blocks to bridge the gap left by the wider SBR bearings to the gantry sides when they get replaced.
  8. Any interest in a guitar specific CNC design?

    I meant, you appear to have used Hiwin equivalent rails/bearings on your build. Mike.Mara is looking at using supported rail (coded 'SBR' by Chinese auction sites) which may have limitations on which way around they are oriented for maximum strength. My comments referred to installing the SBR rails in the same configuration as your method to give maximum strength to a product that may already have inherent weaknesses.
  9. Any interest in a guitar specific CNC design?

    For all I know the recommendations may have originated from people poo-pooing the idea of using those rails for a machine being designed to mill steel. Your scope is a bit more relaxed than that, so it may not be a problem in the long run. Anyone trying to mill steel on a MDF machine is likely to destroy the frame and gantry before the bearings give way. As Mike has suggested - one rail top, one rail under. You're also using profiled rails and carriages, which are designed to withstand more force in directions other than perpendicular to the bearing mounting face. Although, the same principle applies to the supported rails that @Mike.Mara is looking at. - they're probably not as resilient as the Hiwin types, but mounting over and under will maximise their strength and stability given the circumstances.
  10. Any interest in a guitar specific CNC design?

    Router with pattern bits and a straight edge to follow will give you pretty good straight cuts with a perpendicular edge, which will get you out of trouble for most of the major components. Most of the parts in a CNC are in pairs, so once you've made one of a widget, you can use that widget as a template for the next one. Mike's printed labels as templates is a good idea, whether you work with Al or MDF, provided you can verify your printer is generating accurate images first. MDF to begin with. Your picture of the two bed designs is a good starting point. The MDF version can be stiffened up a lot by adding cross members as you've done with the Al version. When I was researching my build, the comments I saw floating around about running those types of rails and bearings in the orientation you have done made me a bit leery of using them. The impression I got was that the open-sided bearings that fit those rails will give better results when the forces pressing down on them are mostly in the opposite direction to the open side. The suggestion I saw was that if you swing the rails around 90 degrees so that the bearing runs on top of the bed it may be better in the long run, preventing the bearing openings from stretching under the forces and static weight of the gantry.
  11. Any interest in a guitar specific CNC design?

    Yep. Perhaps need more boundaries laid out for the build limitations. If it's mostly Al with a bit of MDF then the difference in going to 100% Al will be negligible (assuming the builder can machine it properly). If cost is a concern then minimise the use of the expensive stuff and stick with MDF for the majority of the components.
  12. Any interest in a guitar specific CNC design?

    I was actually going to suggest the opposite. If the intention is to make an a machine capable of acceptable precision at rock bottom prices, then the Al extrusion framing is probably overkill. Cutting the extrusions squarely for the home builder will be difficult unless they have access to a decent quality drop saw with a metal cutting blade. What about limiting the metalwork to only the rails and bearings?
  13. Any interest in a guitar specific CNC design?

    Sounds good. I'd also add a square, router with pattern-following bits, brad point and forstener drill bits (if we're still looking at an MDF-framed machine), steel ruler big enough to cover the longest edge, a compass or trammel. Most of these items a DIY guitar builder will likely have access to anyway. If you can keep it within the realm of 'doable by somebody with a modestly equipped workshop', it is more likely of success. The added cost of third-party cutting and shaping is likely make it a non-starter compared to buying a CNC6040 off eBay. Perhaps the JGro CNC might be a good basepoint to get some ideas from?
  14. Any interest in a guitar specific CNC design?

    I knew the parport was supported in Mach3, just wasn't sure if a plugin PCI parport would cause issues. I'm not pushing a spindle around over large distances for production runs, so blisteringly fast speed isn't big on my list of priorities and I can live with direct parport control for now.
  15. Any interest in a guitar specific CNC design?

    Only as I've said above - factor in how the DIY builder will cut and drill the necessary components that may require a certain degree of minimum tolerance. The two endplates with the bearing mount drill holes ,and ensuring baseplate extrusion is cut squarely at the ends where the endplates butt up against are good examples.