Vodkaman

Liv4Nov - 'Made in USA' is probably a bit of a stretch. You could probably get away with 'Assembled in USA'. Dave

Before we get into the micro switches, there are some safety issues that need to be addressed and wired into the whole operating system. Here are a few discussion points: Motor Control Rules 1 – Protection guard MUST be in place before cutter can be switched on (micro switch MS1). 2 – Cutter must be raised before switch on of 12V system (micro switch MS2). 3 – Cutter MUST be running before 12V travel circuits enabled, common power switch. 4 – Cutter direction test isolation (micro switch MS3 and MS4). 5 – Cutter direction (DPDT switch) 6 – Reset travel. Cutter off MS1, cutter raised MS2, set direction, max speed to MS3 or MS4. 7 – Woodblock MUST be turning before travel enabled. If any of the above rules are broken then a machine catastrophic crash could occur. Make sure you understand the above and the consequences. Each of the above could be controlled manually, but if you make a mistake or miss a step then a crash can occur. Example 1 - Cutter power is off, cutter in down position and travel screw motor started. Example 2 - Cutter down when power on. Example 3 - Woodblock motor stalled while drive screw operating. And more scenarios. Machine needs to be fool-proof. Dave

Without CAD expertise then the 3D printer idea is going nowhere. CAD is not such a big deal, it is just learning time, and after learning it requires regular practice so that the learning sticks. It would be nice to see a lure body CAD library set up for TU members. If this happened then I would volunteer to create a few models for printing. Dave

Welcome to TU. Friendly hint - make your titles meaningful. 'Plastic Suppliers' would be much more helpful than 'New'. Good luck in finding what you want Dave

The reversing switch is done with a DPDT (Double Pole Double Throw) switch. These come in various forms; rocker, toggle, push on/off etc. They all have 6 connectors. Here is a rocker DPDT switch. The PWM outputs (+/-) are connected to p3 and p4. P1 and P6 are connected together and connected to one side of the motor. P2 and P5 are connected together and connected to other side of the motor. I need sleep, it is 6am here, so I will look at micro switches tomorrow. Read the link and my text and make sure you understand what is going on. Different makes of switches may have different pin numbers. Be prepared to test with a meter and adjust design. Update - I think I have the solution, wiring the micro switches into the DPDT switch. I will draw up a diagram tomorrow. Dave

OK, good information. PWM unit is a good choice, you don't have to build anything which was my nightmare. Your information states that the motor is reversible simply by reversing the supply, this is good. So, all you need now is a limit stop and reverse circuit. I will have a think on the micro switches and a simple reversing circuit and get back to you. Dave

Yes, as you hinted, only motor-2 needs to be reversible. There are two main types of motor speed control: 1 – PWM. Pulse Width Modulation. This circuit supplies the motor at full voltage and current but in a series of on/off pulses. The wider the pulse then the faster the motor turns. Basically you are switching the motor on and off very rapidly to control the speed. 2 – Voltage control. This is what you have in mind in your description, varying the supply voltage through a variable resistor. This is the method that I will discuss further. You cannot use a simple potentiometer (pot) because the pot has to be capable of carrying the current drawn by the motor. A large pot might be capable of carrying say 100mA, but the motors for this project are likely in the range of 5W – 10W power rating. This means a current draw of 0.5A to 1A or even higher depending on the spec of the motor and the load that it is turning. You have to use a low power pot to control a mosfet which in turn controls the motor voltage. I am very reluctant to get involved with electronic advice with an electronics novice and seeing that I have never done any motor speed control or used mosfets before. But, this looks like the simplest way to go. But, components have to be chosen that can handle the power rating of the motor. You must provide as much information as possible. I will try to assist you but I will NOT be taking blame. Reading the motor label, what information is provided; voltage, current, power etc. What type of motor is it; A/C, DC, induction, stepper etc. Have you tested to see if the motor reverses when the power cables are reversed? What is the speed (rpm) of the motor? Dave

There is something very cool about extremely matured students, so I am told Dave

That was the machine that inspired me. Dave

CAD is like CNC. It requires a lot of learning AND a lot of practice to keep the learning. These specialized skills are not something that you can use once a year and expect to return to flawlessly. CAD, CNC and other specialized skills are NOT like riding a bike! This post is not a cheap shot at anyone, simply a warning of what is required. Dave

This is a very interesting point. The rocking from side to side is the very start of vortex shedding, the phenomenon that makes lures waggle. The action is speed related, there is a minimum speed that the rocking starts. The minimum speed is also dependent on the shape of the body. A sinking body, the minimum speed is fairly slow, for a lipped crankbait moving forward, the minimum speed is faster. It is all about Reynolds number in fluid dynamics, and I promise NEVER to mention this EVER again Dave

The body material with only a 10% microspheres is very dense. This gives a good weight distribution, the tiny 5g ballast balances out the rear hook. So yes, I think the lure will work well. Dave

There is a technique were you cover the epoxy application with kitchen wrap. This would drastically reduce your clean-up operation. Dave

Yes, epoxy for belly slots, Bondo is not strong enough, more of a hold in place thing. I use a flap wheel in the drill press for the final sanding process. New wheels are not so nice to use, but once they are worn in they are great for lures. Through drilling for a distance of 2" is very easy and is 100% success rate using the spiked plate method. Using the back slot method, the harness does not literally need to be one piece. If I was to build another back slot lure, I would twist the drop eyes separate with a loop at each end. Inserting the drop eye from the bottom, the back harness can be threaded through the small loop. This allows for a smaller diameter drop hole. This is just as secure as a one piece through harness. Dave

My solution was a Bondo style filler. It is fast curing and sands well. I prefer my slot down the back of the lure rather than the belly, this makes the slot filler less significant as it cannot be ripped out. Dave

Mark - direction is random. Dave

I invented my own wood block holder. Basically spiked plates that did the same job. Not brilliant or time efficient, but got the job done. Dave

The speed I found was limited by the bounce of the follower on the master and/or the cutter on the woodblock. I found that around 60rpm was the limit. If you can solve the stylus bounce issue then you can get more speed. If you can automate the run with an auto-off micro switch then speed is not really of great concern. What is of most concern is the finish or step distance between cuts. The finish is not going to be smooth, but how much rough can you live with. Finish is down to cutter step distance. I liked 0.5mm on my machine. It still required a 30s touch up with a flap wheel. Dave

Motor power and speed control is an issue that deserves some research. For small low power motors a potentiometer will work, but for more powerful motors requiring more current, you may have to find another solution. I chose a wiper motor because they were the correct speed for my project, easily available 2nd hand and easily enough power for the job. Dave

You seem to be on top of the project. The ballscrew looks like a good solution, it should eliminate the slop. You have eliminated the bending, and good machining practices will eliminate the adjustments. Dave

I am not going to advise you on your choices because I do not have practical experience of those choices, all I can do is pass on experience gained from the choices that I made. There is simple math to help you with deflection questions. You can Google deflection calculations. You can then decide whether it is a good solution for you to support your cutter carriage on the threaded drive. Decide in your head what is an acceptable deflection, say 0.5mm. This would give a cutting error of 1mm (twice the deflection error). Then collect all the required information and do the calculation. Other problems to be considered in your design are spindle alignments. You have three major spindles spanning the machine; the woodblock spindle, the master spindle and the cutter carriage spindle, and ALL must be in perfect alignment. If the side plates are cut by CNC or a skilled machinist then the alignment problems will be minimal, but if you are cutting yourself then you had better build in some adjustment, and figure out some procedure for performing those adjustments. I am not trying to discourage you, merely identifying the problems that you will face. Best advice is to build the first prototype with the understanding that a 2nd prototype WILL be necessary to solve the problems identified in the first build. My first two builds never got as far as mounting motors, they were both hand cranked. Proto3 was slated to use a 12v car wiper motor. Dave

OK, now you are getting down to the real BONES of duplicator problems; the drive screw. The two major drive screw problems are deflection and slop. In my first duplicator build I basically ignored these two issues. Deflection - sling a threaded bar between two bearings and hang a 2Kg weight on the thread and there IS going to be deflection of the bar. The deflection depends on the diameter of the bar, the distance between the support bearings, the mechanical properties of the bar and the weight of the carrier. Slop - Basically the tolerance of the thread and the fixed nuts in the carrier. If you are using precision drive screw then the tolerances will be tight and the problem eliminated with $$$s. If you are using standard issue threaded rod (as I did) then you are in for a world of problems with repeatability. Slop and deflection will give you an end product that is significantly different to your master. For me, an expensive machined drive screw was not an option, but in terms of cost and availability. I had no choice but to go with standard threaded rod. Even though I did not deal with deflection and slop, I was happy with my results, but the differences between the master and the product were a concern, but the results were consistent. However, before I could build the design that tackled the problems of deflection and slop, I was evicted from my house and lost everything that I had done, my workshop, templates, machines and tools were all gone. I did build a second machine before I lost the workshop. It addressed the deflection issue, but it was not a good solution. If I were to build a third prototype, I would still use 12mm dia standard threaded rod with a 1mm thread pitch, I would support the weight of the cutter machine on separate rails, thus leaving the threaded rod to push and pull the carriage with no bending loads. The slop can be taken care of with some thoughtful, creative design. I found solutions by Google. Dave

Good choice of cutter, you seem to have a good understanding. The solution is gearing. The travel threaded spindle rotates at half the speed of the master and woodblock spindles. You can see in the image that the master and woodblock spindles are driven by the motor. What you don't see is the bicycle chain gearing to the motor carrying spindle geared at a ratio of 2:1 Dave

JD - The spherical domain enclosed by the tall man's spell of 4πr³/3 is an intriguing and fascinating subject. It is the simplest shape and yet the most difficult to carve. I have actually experimented with spherically derived shapes and the resulting actions are interesting. If you pull a sphere through water you get a pure spiral action. I do most of my cranial development work while sleeping, so you could say that I work in an alternative universe Dave

The forces are at the edge and rear face of the lip, but let's not make this a science class pop-quiz. Dave