Sewing With An Electrically Heated Inner Presser Foot !?

[Uwe]

I came across this video by an Italian company Zallocco where they use an electrically heated inner presser foot to sew a belt. I haven't quite figured what the (heated) point of it is and my Italian is quite bad beyond ordering espresso based drinks.

Are they just shaping the needle hole for visual appearance? Perhaps the presser foot has a specially shaped bottom to make an impression in the leather as you sew. They must not be using nylon or polyester thread with that heated foot.

Has anybody else seen or used this, or know exactly what they're doing here? How does that heater rod even work with just one wire going to it?

That modified, welded-on big-foot outer presser foot is interesting, too - definitely not leaving any marks on the leather! Too bad they don't show what the underside looks like.

Edited March 1, 2016 by Uwe

[Uwe]

Today must be Italian heated presser foot day. Another italian video shows a (broken and rather unsafe looking) heated presser foot machine in action at the 1:51 mark (what sewing machine is that?) I also realised that I'm not wearing nearly enough gold jewelry when I do my leatherwork.

[BigMatt]

If you look at their belts, it looks like they are making impressions at the stitch holes. It gives an interesting look.

The heating element has two wires (I believe). There might be a coaxial system to deliver electricity to the heating element like the filiteuse manuelle.

Edited March 1, 2016 by BigMatt

[TinkerTailor]

I would guess they are using the heat to get a stitch groove in chrome tan. The harness feet everyone uses on veg to sink the stitch would not work on chrome tan. The thing is, hot impressions take at least a little contact time, i am not sure there is enough time at full sewing speeds to make a mark, and the depth would vary with speed. The leather may even burn when stopping to turn a corner.

As to the single wire, it could be a negative ground DC circuit like a car in which the frame of the machine is the negative pole.

[BigMatt]

As to the single wire, it could be a negative ground DC circuit like a car in which the frame of the machine is the negative pole.

I thought about that, but that would cause erosion since the current would be running through moving surfaces (gears and bearings). Don't you think?

[TinkerTailor]

Totally. Arcing through bearings is not good. They may have a negative on the presser bar above.

[dikman]

I would say that they must have an electrical connection somewhere on the needle bar. You won't get very good conductivity via the oil that the bar should be running in, and as you say any arcing would be an issue.

I'm still trying to figure out what use it would be

[LumpenDoodle2]

I did a google (ooh er, missus) and came across a US patent 1921/22 which claimed the heated presser foot 'ironed' the seams.

Could these machines have previously been used to iron on stabiliser to the back of a fabric seam.

Edited March 2, 2016 by LumpenDoodle2

[Uwe]

It certainly looks like a technology or method that was invented when operator safety was a secondary concern. For myself I've concluded that this particular oddity in sewing technology is skippable. I don't feel the need to add burn marks and electric shocks to my personal list of sewing hazards. I'll stick with cuts and punctures for now.

[TinkerTailor]

The burns cauterize the cuts. Its a win-win.