Help! How To Relieve Foot Pressure On Consew 206 / Foot Leaves Marks

[Uwe]

Geek alert!

I've been giving this some thought because that foot pressure business has baffled me for a while and the inner foot spring setting never had any noticeable effect no matter how I adjusted it.

I've concluded that the inner presser foot spring shown in your picture has only little, incremental effect on how hard the inner presser foot presses down on the leather during the stitch cycle. Changing the spring or cutting a bit off will also have minimal effect.

This sounds weird and counterintuitive but the OUTER presser foot spring ALSO determines how hard the INNER foot presses down when outer foot lifts up. The pressure of outer and inner foot are NOT independent of each other, in fact they're closely and quite literally linked. This is because the outer foot actually uses the inner foot as leverage via linkages to lift up, against the spring that controls outer foot pressure. If you remove the inner foot entirely, the outer foot will not lift up at all because it needs the inner foot as leverage to press against the material in order to lift up.

I believe the main purpose of the inner presser foot spring is to ADD incremental pressure to the inner foot on top of what the outer foot spring already provides. Adjusting the inner spring will never allow you to lower the inner foot pressure below what the outer spring dictates.

I just now did a little experiment to back up my claim with some proof. I put a kitchen scale under my presser feet bars and moved the needle bar up so as not to interfere. I dialed the outer pressure foot spring low enough to get below the 10 lbs weight limit of my scale. I removed the inner presser foot spring adjustment knob entirely, so the inner spring was not pressing down at all.

With this setup and the inner foot spring totally out of play the outer foot bar pressed down registering 7.2 lbs:

and after turning the wheel a little the inner foot bar pressed down with 5.5 lbs:

The difference is likely due to linkage angle and lever lengths, but the two are proportional. If I dial up the outer foot spring pressure, so increases the inner foot pressure (all WITHOUT the inner foot spring involved at all)

Adding the inner foot spring control knob (the one in your picture) and cranking it all the way down for max inner foot spring pressure increased the inner foot pressure an additional 2.5 lbs over the initial value. This is the max the inner spring can ADD to outer spring.

The inner foot is also more likely to leave a mark because it has a much smaller footprint than the outer foot and exerts higher force per square inch with the same spring pressure (the skinny high heel of a shoe is more likely to leave a mark than the bigger front of the shoe, but your weight does not change as you walk.) So the small inner foot even at 5.5 lbs is much more likely to leave a mark than the bigger outer foot at 7.2lbs

I'd try dialing back the outer foot presser spring until it just barely holds on to the material when you tug on it and see if it makes a difference. Help guide the material with your hands as you sew to allow the machine to move the material easily and consistently with minimal foot pressure. Don't push or pull as it sews, just allow the machine to do the work with minimal force.

Sorry about the long and geeky post, but I hope it adds some clarity to this confounding foot pressure business.

Edited January 31, 2016 by Uwe

[Northmount]

Geek or not, great work, great diagnostics. Much appreciated.

Users need to remember to keep enough outer foot pressure to keep the leather from lifting as the needle rises, else you'll be into skipped stitches ... You don't need a lot of extra pressure. It will vary with leather thickness and temper, as well as needle size.

Tom

[Don Ayres]

I'm a bit confused which is the inner presser foot and which is the outer presser foot and which one primarily controls the amount of pressure, can someone clarify this for me.

Thanks

[spurdude101]

 

What I did with my Cowboy 4500 was take a hot glue gun and coat the presser foot with a glob of hot glue, after it dries take a file or grind off the excess on the underside leaving a 1/16 " of glue material on the foot. Works great. No more metal on leather marks.

Edited May 14, 2021 by spurdude101