Author Topic: Adding auto-backtack to a Tacsew T111-155  (Read 768 times)

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Misadventure Gear

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Adding auto-backtack to a Tacsew T111-155
« on: June 27, 2019, 01:14:47 PM »
Looking at upgrading the servo motor on my Tacsew. The motor https://store.keysew.com/catalog/product/7ccbeb40bd4c4f328811719b1d70cfe1 I'm looking at has the ability to do auto-backtacking. Can anyone tell me what sort of additional hardware I'll need to connect to my machine's reverse mechanism to make it happen?

SunriseTacticalGear

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Re: Adding auto-backtack to a Tacsew T111-155
« Reply #1 on: June 27, 2019, 06:49:23 PM »
Give them a call they will help determine if this motor is doable. About 6 years ago I explored a needle positioning servo for my Tacsew and he wasn’t able to determine what adapter I would need to attach it to my hand wheel, so my dream came to an end.
I ended up purchasing some servo motors from them (non needle positioning).
Scott
« Last Edit: June 29, 2019, 07:10:32 AM by SunriseTacticalGear »

essal

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Re: Adding auto-backtack to a Tacsew T111-155
« Reply #2 on: June 29, 2019, 03:15:35 AM »
If you can get a mechanic to come look at your machine, determine what's possible and pay for the install, I think you'll have a better time.

Just looking at my 30+ year old Juki at work, I can't figure out what exactly was added to it when they added the computer.
Nora Tactical
Product Technician - Norrøna

Misadventure Gear

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Re: Adding auto-backtack to a Tacsew T111-155
« Reply #3 on: September 01, 2019, 03:38:09 PM »
Update on my Tacsew T111-155: I gave up on the idea of adding foot lift to my Tacsew. Machine compatibility issues aside, the solenoid and other hardware would run $400-$500 on top of the servo motor. In the end, I ordered the SP-1100NPFL servo motor with needle positioner from Keystone. It took about 2 weeks to arrive. My excitement at seeing the box on my doorstep quickly turned to concern, when upon picking up the box, a screw fell out. I could only hope and pray that no other screws fell out in transit.

On unboxing, there was little damage to the box or it's contents. However, the ziplock baggie which held several screws was not sealed shut, and I also found a washer floating around in the packaging. Everything else appeared intact. Installation of the motor and control box was straight forward. I removed the old servo motor, now destined for another machine, and bolted in the new one. The motor control box, power switch, and speed control switch which connects to the foot pedal were also screwed in to the bottom of the table.

The fun began when I tried to connect the synconizer to the handwheel's axle. For those of you not familiar with the set-up, you remove the stock handwheel screw, and replace it with a longer one supplied with the motor. This screw secures a round cam, which the synconizer then attaches to. The synconizer counts the revolutions of the main axle, and tells the motor when to stop. To prevent the synconizer from spinning along with the axle, a second L-shaped bolt is screwed into your machine. It sits in a slot on the synchronizer to fix it in place.

Of course, the only handwheel bolt supplied with the motor was the one which fell out as I picked up the box. And of course, it did not match the diameter or thread pitch of my machine's stock bolt. Furthermore, the L-shaped fixing bolt also did not fit the existing screw holes in my machine for attaching the belt guard. The holes were also not in a good place for the fixing bolt to engage it's slot in the synconizer properly.

To install the fixing bolt, I ended up removing the handwheel, then drilling and tapping a hole in the side of my machine's pillar. First, I positioned it so it just cleared the handwheel, and then verified by looking inside the pillar, that I wouldn't accidentally hit something vital inside. I was able to position it in a thicker part of the wall, and drill a hole nearly ½" deep without breaking through to the inside. Tapping it to match the L-bolt was easy enough. As an alternative to drilling and tapping, I could have bent up some sheet metal and screwed it to the table top to fix the synconizer in place, but then I would have to remove it every time I wanted to tip the machine back. With the fixing bolt in the pillar, you don't need to do anything.

Replacing the main axle bolt proved the be the hardest and most expensive part of the upgrade. The rather generic instructions showed three different bolts, advising you to use the one which fits your machine. It even listed the sizes, one of which, 11/32" diameter with a 28tpi, matched the screw from my machine. Assuming that I probably lost the screw I needed in shipment, I called Keystone for a replacement. They were less than helpful. They did not have any motors to look at to see what I was talking about. I'm guessing the motors are probably drop shipped from the distributor, and not kept in stock by Keystone. After a few phone calls and some pleading, they sent me a bolt which wasn't anything close to the measurements I provided for the missing one. They also made it clear that they wouldn't help me anymore.

Exercising my Google skills, I confirmed what I already suspected….. You're not gonna find screws in an 11/32" diameter. It is possible to find screws with an Extra Fine 28tpi (threads per inch), but only in ¼" and ⅜" diameter. Taking my screws with me, I went to see my local automotive machine shop to have one made. It took them a couple weeks, and I also needed to bring the machine head down for test fittings, but they were able to do it. The machinist told me he's never had to cut a bolt like that. The unusual diameter, and high precision called for by the Extra Fine thread pitch made for challenging work for him, as he had to remove the screw from the lathe for test fitting several times, then chase the threads again once back in the lathe. His skill and excellent work made the $135 bill for a single screw more palatable. As I reminded my wife, good work isn't cheap, and cheap work isn't good.

Once back home, the synconizer bolted right in. I'm still playing with some of the control settings, but I really like it. I have it set up where the needle stops in the down position. A firm heal press raises the needle. It's taken me very little effort to get used to it, and I see this being a great time saver over time.  Aside from the drama surrounding the missing screw, installation was pretty straight forward. I'm interested to hear if anyone else has ordered this servo, and if it came with 3 handwheel screws or only one. Photos can be seen at

Tacsew T111-155: installing needle positioner https://imgur.com/gallery/PKgULOR
https://imgur.com/gallery/PKgULOR
« Last Edit: September 01, 2019, 03:57:55 PM by Misadventure Gear »

SunriseTacticalGear

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Re: Adding auto-backtack to a Tacsew T111-155
« Reply #4 on: September 03, 2019, 06:09:25 PM »
Thanks for the update, your persistence is commendable. I think I would have either tapped the hole to something close or jammed a screw in that hole, for a one and done. LOL
Scott

Misadventure Gear

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Re: Adding auto-backtack to a Tacsew T111-155
« Reply #5 on: September 06, 2019, 11:27:46 PM »
I couldn't have gone bigger without also having to drill the steel inner cam, along with the end of the main axle shaft. I highly doubt I could have done that with a hand drill and kept everything square. I even asked my machinist if he could just weld the cam to my stock screw, but same answer. Keeping it all perfectly square would have been more difficult that just turning a new bolt on a lathe.