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Messages - SARK9

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1
Materials science / Re: Face Masks
« on: April 17, 2020, 02:18:56 AM »
In terms of the functional liner material, I have been using a similar product to the one shown in this site: 

https://www.healthcarepackaging.com/home/article/21124863/second-life-sterile-wrap-fashioned-into-masks

I get mine is 20"x20" sheets in boxes of 500..there are several brands, weights and types of this surgical sterilization wrap...its a non-woven material with properties that make it pretty spot on for use in masks. Works well. I sometimes use an 80/20 polyco fabric outer shell. #9 needles and T-15/T-30 thread for assembly.

-DC

2
I've had to supply power to several of my own machines (not sewing machines) set up for 3ph power...lathes, mills, large saws..etc. I currently use a "roto-phase" type converter rated for the largest HP motor I use. This unit is powered by a normal single phase 220V input, usually available in most residential load centers. Some of the larger saws I have used in the past were supplied with "static phase converters" which are small, quiet and all electronic, but note you do take a small HP hit with either the rotary or static converters. I believe the hit is less with an actual rotary, but that is probably an academic concern with most industrial sewing machines which do fabrics. Variable frequency drives are normally used to provide a 3ph motor with some programmable or on-demand functions like speed control or reverse etc....nice if you need or will use it, but you will most likely just want the 3ph conversion to supply the main input on your machine. I'd investigate a "static phase converter" and see if you can determine if there are any gotchas which lie in wait if your main connection is ONLY the 3ph input, and the brain on your machine steps down and converts all the power and voltages for the other electronic/computerized functions.

-DC

3
Concept, design, and engineering / Re: 3d printed foot
« on: December 02, 2018, 09:44:15 AM »
Cool idea! The outer foot should only trap the fabric in place between the stitching actions of the needle feed and lower feed dogs...if your stitch has shortened, it may be because the lifting of your new foot is a bit late and it has locked the fabric in place slightly during the stitch movement. There is considerable variation in the aftermarket copies I'm familiar with for the similar 111W style of feet, and they sometimes need to have the foot lift timing adjusted slightly. Yours may be a tiny bit long. Its an easy adjustment on the 111W or Juki563 type machines, but I don't have a Pfaff to check on.

-DC

4
I've just recently acquired a pristine Mitsubishi LS2-180 (equipped with a functional Mitsubishi LimiStop Z unit...120-V 1ph) and need some advice or possibly pointers to documentation or forums/groups where there may be some discussions about programming the various functions.

Particulars: Main motor- Type CA-Z402E
Control Panel: LF-C8

Hardware functions installed; (all are electric solenoid operated) - Needle positioner, programmable backtacking patterns (plus momentary manual feed reverse switch), thread undertrimmer/wiper, foot lift, various combinations of the above motions, and electronic eye start/stop material detector.

I do have a couple of manuals for similar but not identical models...there is a bit of variation in the dip switch settings. The dip switches and internal VR settings are clearly labeled with mystic acronyms, but their functions are described in extremely economical language with just a hint of "all your base" syntax. The main mystery is whether some of the desired behavior is dependent on certain external controls plugged into one of the two "option" plugs on the main motor's connection array.

The main problem I have with the current state of options selected...the foot pedal is programmed to behave as an on/off switch rather than an accelerator-type RPM control for the motor. None of the heel-back functions are available. RPMs are selected with an external dial on the main motor panel, giving only this pre-selected rpm while sewing. There is convoluted language in my near-miss manual pile that hints that the accelerator-type external RPM pedal control may be provided by another external device plugged into one of those options sockets. It appears I will need the EXACT manual for this model or a talk with someone who has its twin to get a good grasp of what this all actually means.

I can get the machine into a useful state by selectively disabling some of the conflicting ops as needed, but the machine as-is is pretty astoundingly quiet in operation, and it seems a bit of a shame to dumb it all down to another "brushless servo", a 24V transformer and some of its manually controlled switches. Just throwing this out there.

Regards-

DC






5
Materials science / Re: Mixing thread sizes - Top & Bobbin
« on: April 08, 2018, 06:59:17 AM »

[...]Are there any negatives to mixing top thread and bottom thread of different size? T-90 and T-70 work well so far but could I get up to T-135 topstitch with T-70 bobbin?



I use a good bit of black fabric (usually 1000D) on machines that will run T-90 or T-135 top thread, but are cursed with small bobbin capacity (mostly G, but sometimes L or A style bobbins, or the miniatures used with 29K style patcher machines). I use T-45 Kevlar thread in the bobbins to roughly match the tensile of T-90 poly (14lbs vs 14.5lbs) so that is a good match on paper, and T-70 Kevlar is a match for T-135 poly. Vastly more T-45 fits on a G bobbin. Mostly this is useful for assemblies where the bottom stitch is hidden, inconspicuous, or absolutely pragmatic, and the color selection for Kevlar threads is....not good. I don't find the appearance on black to be all that objectionable, but of course that is subjective. Also, any remaining thread tails cannot be burnt or melted, and you'll want sharp scissors, but certainly not your favorites. I've *not* used it for lower thread on a machine with an automatic undertrimmer.

-D

6
Materials science / Re: Needle and Thread for Industrial Machine
« on: March 03, 2018, 07:01:10 AM »
A standard (unmodified) Juki LU-563 uses the 135X17 needle for fabrics, or the 135X16 type for leather. Both are available in multiple point styles and a large range of sizes with coatings if desired. Several of my fabric-type machines take the much shorter DPx5 needles shown on your link. Its not correct for your Juki.

-DC

7
Here's a chart with bobbin style/dimensions. You can measure yours and look for a match, then shop for that style.

-DC

http://hensewfiles.com/General%20Information/Bobbin%20Selection%20Information.pdf

8
Workspace, tools, machinery, and manufacturing / Re: Cylinder arm machine
« on: January 07, 2017, 08:23:47 AM »
Looking at getting a cylinder arm machine for building and repairing packs. right now I am looking at a 341 clone (Atlas AT3341) wondering if anyone has any thoughts or insights on cylinder arm machines. Any idea what the Atlas AT8B is a clone of? Thanks!

I think the model number suggests that Atlas has "cloned" the Seiko CW-8B-2, which is sort of academic since the Consew branding was originally a Seiko marketing dodge. I think they are all adaptations of the Singer 153 to some degree. I use a Mitsubishi CU-865-22, which as an even more convoluted heritage involving Pfaff 335's and Singer 211's...

-DC

9
Introductions / Lurker's greetings from SWVA
« on: January 02, 2017, 04:21:48 PM »
Happy New Year to all... 

One of my resolutions for 2017 is to quit lurking and dive in. At the moment, I am a *medium serious* hobby-level custom gear maker, mostly specializing in things of interest to my fellow SAR K9 handlers and other rescue personnel. My day job limits how far I can take this for the moment, but I'm content to call this period "R&D* since most everything I do is evolving. I appreciate the members of this forum for sharing what they can in a way that assists newcomers like myself, and I hope to take my hobby a bit further in the future. Thanks for hosting a great forum!

DC

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