Vodkaman

I haven't built a popper myself, but I do understand the concept; gather the water and squeeze it out the top to make some splash/plop noise. A vertical cylindrical shape would achieve this result, particularly with a lip at the bottom of the face. Many commercial poppers show an kinked/angled side profile which hints at the same idea; gather the water and force it upwards. Dave

You have made a solid start. Plainly, you understand the eye socket issue, and you will be applying these cutter thoughts to your future designs. As for the 2nd part, the buoyancy thing, I can see your line of thought because I went down that line myself, but wrong. The upward buoyancy forces are all about Archimedes, volume displacement of water. The total external volume of the lure generates an upward force of 1 gram for every cm³ of volume. The CAD COG of this uniform density volume will give you the COB. Dave

It must be SOOO frustrating for Curt. Personally, I would throw ALL the rule breakers out of the competition. Dave

DGFidler - good project. The CAD model of the flat sided body is as simple and uncomplicated as it gets. I only see one issue with the design and that is the eye socket. If you intend to use a ball-end cutter or a cutter with a radius then this result is not possible. Secondly, be careful regarding the calculation of the COG using the CAD software. The COG only takes into account the downward forces of the body material, the ballast, hooks, lip and other hardware. The buoyancy forces are not considered, and for a lure that actually floats, the center of buoyancy (COB), the sum of the upward forces is actually greater than the COG which is the sum of the downward forces. The COF or Center Of Forces will be about half way between the COG and COB. This is a complex idea that is going to hurt a lot of heads and burst some balloons regarding understanding COG. This detail will likely not be important to your bait, but when the lure is static in the water, the center of forces, the sum of the upward AND downward forces is not the same as the COG. The problem arises if the two forces are too close together, again most unlikely otherwise this would have been discussed before. The beauty of knowing the COG and the COB is that you can then accurately predict the float angle, the attitude that the lure sits in the water, be it nose up, nose down or level. It is then possible to alter the position of the hooks and ballast at the CAD design stage to control the float angle. I will write in more detail about this one day and try to make it clearer. But, the information is only of advantage to CAD designers, manual designers will have to use the 'suck it and see' method. Dave

Introduce a CAD design section and I will submit 20 images from different angles Dave

Such poor quality, certainly not around, or infinitely better now Dave

Curt - I am confident that this year will be different and EVERYONE will read the rules and follow to the letter. Good Luck Dave

I must have missed this video, first time I have seen it. The video highlights a few problems for the CAD designer in that you have to be aware of the milling process and the tool radii required. You can start with a very pretty CAD model, but after the machining process you end up with an unrecognizable mush. It would be a lot more interesting to see a video of the complete CAD design process that people use with the different CAD systems. Dave

Big Epp - good summary, I agree. If I ever brought a crank to market, I would probably do a Henry; 'you can have any colour you like as long as it's black'. Dave

If the bit that you trimmed off was EPS then you have removed some of the 'float' capability. From an engineering point; you have reduced the volume but kept the weight the same. It would have been a good idea to start a new thread for this question. Dave

Don Mang - you cannot pot these pics (last post) on this thread, they need to go in the gallery. The pics are not relevant to the post. All 'look at my work' pics go in the gallery. Dave

The TU management team is VERY proactive against spam, removing the unwanted intrusions as quick as they can be reported. AND, it is up to the members to report these spam posts. One spammer seems to have managed to dive under the detection net by actually spamming in the correct forum for sales; the advertising forum. It is still spam, as the membership should not be interested in lipstick boxes, beard oil boxes or any other type of liquid box. I hope the management manages to plug up this loophole soon. Thanks for your hard work in keeping this forum site clean. Dave

I agree with JD. I build baits in this size range and all I have is 6 & 4. This is another one of those cases were 'if it looks right then it is right'. Dave

For me, position is primarily a structural thing; a deep enough slot for a solid connection and enough body behind/above the slot for support. Waggle is a force x distance or lever thing, so the further away from the COG then the more waggle you get. If you simply move the lip rearwards on the next prototype, you will likely have a different result or even fail, because the geometry to the tow eye has changed and disturbed the balance. You may have to experiment to find the new eye position. Be mentally prepared to make a few prototypes. Make one adjustment at a time and make notes. Always test with hooks and hardware fitted. Dave

Exx1976 - I do not understand you. I have refrained from posting this sentiment before. You put a lot of effort in, making excellent contributions to the TU community, gaining a lot of respect. And then, you seem to have a brain fart and chop someone off at the knees for very little reason. I am not blame free, I too have had my moments of indiscretion. I suggest you think your more acidic replies through before hitting the reply button! Dave

I felt quite chilled last night as the temperature dropped to 24°C (75°F) inside the house. It could have been as low as 21°C (71°F) outside. I may have to buy a blanket! Daytime is usually no problem high 80s°F to mid 90s°F. When I start house hunting in April, I will be looking at 500ft lower altitude, this will buy me an extra degree or two. Dave

You could go with a converter, but make sure the converter can supply the power for the motors. 'Gear/chain/pod', not sure what you mean here. Dave

Ravenlures - I built my second duplicator for cutting 8" bodies of meranti wood which has a density of 0.55g/cm³ to 0.68g/cm³. Cutting was no problem as the depth of each cut was less than 1mm. I was experimenting with multi section swimbaits at the time and needed a healthy supply of bodies. Hand carving soon became very old. I used bicycle chained gears for my machines. The method was successful but very limiting. I used 2:1 ratio (88 - 44 teeth). I guess 3:1 would have been possible but the gear diameters were very large and bordering silly. Any future machines will definitely be motor driven. If the motor can move the carriage then it is strong enough. Very little load is added from the actual cutting process. Depending on the dimensions of your bodies, you may have to mount a larger cutting wheel, I went with a circular saw tool rather than an angle grinder tool. I think the grinder will take a larger wheel. Dave

Jason - I found a very simple solution to the lip slot issue. Use a short stub of PVC pipe as a mold, sitting on a ceramic tile or glass. pour a Bondo filler mix into the mold. grease up a duplicated blank and push into the Bondo, about half way. Once cured, the greased body will easily pull out. On the side of the Bondo cylinder, a flat can be ground on the belt sander. This flat will enable you to cut lip slots on the band saw. Plenty more jig opportunities will come to light once this basic jig mold is made. All holes and slots can be cut rapidly, with minimum effort and total accuracy and repeatability by using a series of jig molds. Dave

Ravenlures - yes, slowing the screw improves the finish. I do feel some confusion. At first I could not see the video and only had the image to go by. To me, this image represented a finish similar to what I achieved with a 25tpi screw. So, I assumed a faster screw rotation to what I saw in the video. For the main screw rotation speed in the video and the master rotation speed, I expected a much finer definition. I must admit that in my mind I was a bit disappointed as I wanted to go down this same route myself on my next duplicator design. There is a limit to how slow a motor can go under Pulse Width Modulation control, but the slow speed in the video was VERY impressive. I look forward to a photo that shows what the best possible definition looks like, particularly over a sloping section of the master. Dave

Seele - yes, too bad. When CAD design becomes more prominent along with 3D printing then people will be crying out for this information. Dave

Ah yes, I understand now. I used a 6mm diameter stainless rod to through mount my masters. I would fix the block on the rod before carving. Agreed, a round profiled saw blade would be a good solution. I couldn't find anything locally. Perhaps it might be possible with some sharpening rig, I have not researched the idea. I really like your rotating follower with what looks like a O-ring contact. This would eliminate the problems of master wear that I had. I do think that the follower needs some means of adjustment for the next evolution. The precision ball screw is really doing its job, the only downside is the threads per inch count which prevents you achieving a finer definition. For my next iteration of duplicator design, I will be looking at M5 rod with a standard thread of 0.5mm pitch, in other words 50tpi. The carriage will run on rails and be pulled along by the rotating skinny threaded rod. This design would allow me to either use a single motor with a 1:1 gear ratio between the spindles and still achieve a 0.5mm definition step, or, use two motors and balance finish against time. Sometimes time is not that big a deal. My design spec is also to produce 6 duplicate bodies per pass. Dave

Jason - thanks for the video. That is excellent. The screw motor set to absolute minimum, the definition is not going to get any better. Very good job, inspiring. The only issue is the end bearing mount for the master, somehow is off center. Ravenlures - You cannot produce this type of lure body on a lathe and you cannot replicate the material density with a mold. The only alternative to this machine is hand carving, so I will take the short clean-up time.

I could not view the video. Message says 'Video unavailable, this video is private'. First copy looks good. I think with some speed and follower adjustments it will improve. Dave

Ravenlures - The main arguments are size of router bit, life of bit and expense. Also, at least half of the bit pass will be against the grain of the wood block. The width of the saw blade is little more than 2mm, also 40 teeth gives long life, and very cheap. The saw blade cuts like butter. Dave