MainiacMatt Report post Posted March 8, 2023 (edited) Here's the groovy new rig... a Chandler 406 RB-1 (Consew 206 RB-5 in disguise) Purchased new from local dealer for $1,300, which was way over my "allowance" ... so I had to economize for the speed reducer. That meant DIY... but I do machine design at work and have access to machine shop and 3D printer so let the fun begin. Here's the 3D model of my design. I found the pair of flange bearings on e-Bay for $15, and go the aluminum plate stock from my stash of cutoffs. The step pulley has 50mm and 150mm sheaves (150 maxed out the printer build envelope). Here's the pulley model prepped for printing with supports in the printer app. Hot off the printer... Edited March 8, 2023 by MainiacMatt Quote Share this post Link to post Share on other sites
MainiacMatt Report post Posted March 8, 2023 (edited) After trimming the supports, I cleaned it up and precision bored the shaft hole for a close fit to the shaft Printed small pulley and bored on lathe as well... AL Plates were milled on the Bridgeport clone after hours at work.... sorry, forgot to take pics. Here's the finished assembly... Edited March 8, 2023 by MainiacMatt Quote Share this post Link to post Share on other sites
MainiacMatt Report post Posted March 8, 2023 Another assembly pic... With the servo motor at its lowest speed setting (the speed dial clicks into position on this model), and the pedal pushed all the way, I'm getting ~2 stitches/sec. If I back off on the pedal, I can slow down to 1 stitch/sec. Control is pretty good and with some care I can cycle individual stitches. I would have liked to go slower, but as noted, I maxed out the pulley size I could print. Thanks for looking in. I realize that not everyone has access to the tools to do this style build, but I gleaned a lot of info. from other speed reducer builds I found posted and wanted to share this as yet another way to do it. Happy trails... Quote Share this post Link to post Share on other sites
dikman Report post Posted March 8, 2023 Nicely done. Just curious, what type of printer is it? The finish looks different to my efforts. Quote Share this post Link to post Share on other sites
DonInReno Report post Posted March 9, 2023 That turned out great! It’s always nice to see a home brew reducer! Quote Share this post Link to post Share on other sites
MainiacMatt Report post Posted March 9, 2023 (edited) 15 hours ago, dikman said: Nicely done. Just curious, what type of printer is it? The finish looks different to my efforts. This is a Form 3 SLA (stereo lithography.... uses laser to cure resin) printer. The layer resolution is quite a bit finer than FDM (fused deposit of molten plastic), but the supports can be a PITA. The resin I used is called Tough 2000, as it's intended to be strong enough for functional parts (as opposed to form only prototypes). On the non-functional surfaces, I just trim the supports and lightly sand the surface, so you can still see the striations from the print layers and pimples from the supports. But when I turned the critical surfaces on the lathe, the finish was very, very, smooth. I'm hoping to try printing some custom graphics for use as embossing tools some day. There's several YouTubers doing so and the results look promising. Edited March 9, 2023 by MainiacMatt Quote Share this post Link to post Share on other sites
dikman Report post Posted March 9, 2023 Thanks MM, I thought it might have been a resin printer but it's obviously way above anything I've looked at. Very impressive results. Quote Share this post Link to post Share on other sites
Metalhorseman Report post Posted March 23, 2023 Awesome! Quote Share this post Link to post Share on other sites
Xaff2442 Report post Posted March 27, 2023 What is the benefit of this design of speed reducer as oposed to just reducing the size of the pulley on the drive motor? Quote Share this post Link to post Share on other sites
DonInReno Report post Posted March 28, 2023 21 hours ago, Xaff2442 said: What is the benefit of this design of speed reducer as oposed to just reducing the size of the pulley on the drive motor? Reducing the motor pulley helps a little, but a separate 3:1 reducer cuts the speed to a third and increases torque by three times - much more controllable for those of us who enjoy sewing slowly. It’s often worth it to add a smaller pulley in addition to the separate reducer. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted March 28, 2023 21 hours ago, Xaff2442 said: What is the benefit of this design of speed reducer as opposed to just reducing the size of the pulley on the drive motor? If you are able to achieve the slow speed control and punching power you need at that speed, you don't need a reducer. However, if your motor power drops too far down to punch the needle and thread trough the work at that slow speed, a reducer will allow the motor to spin faster while the machine turns at the desired slower speed. For instance, I have multiple sewing machines that have analog servo motors like this one. This type of motor has a simple knob on a pot or rotary switch that varies the top speed. At the lowest top speed settings the torque drops down to the point the motor won't turn the machine over without help. I have to increase the speed setting a little to get the machine to turn over. This also translates to a higher slowest speed. If I really need to sew slower, and steadily, at a rate below what the direct motor give me, I can add a speed reducer. Some are 2:1, others are 3:1. This hasn't addressed to part of the O.P's question about the difference between having a smaller motor pulley versus a speed reducer. I would try changing to a smaller motor pulley first. Adding a reducer is a hassle no matter what type it is. Plus, it requires an additional belt. Note, that changing the size of the existing motor pulley may also require purchasing a different length v-belt. Quote Share this post Link to post Share on other sites
