Changing foot fitting · Maintenance

Changing foot fitting by replacing the presser bar

There can be several reasons for wanting to replace the presser bar on your machine, the main one probably being to change the foot fitting. Some machines have really odd foot fittings for which feet are hard to find, for example the old Singer back clamp or the White top mounting foot, or even more modern examples of Japanese super high shank feet, or of course Bernina’s own fitting. 

I have so far converted between Singer back clamping feet, super high shank feet and low shank feet.

Comparing feet

The first thing to remember is that foot fittings vary not only in shank hight but also in the distance between the mounting point on the presser bar and the point where the needle goes through the foot, so both vertical and horizontal measurements have to be compared to decide whether you can convert from one type to the other. 

Below is a comparison of a low shank, high shank and super high shank feet. You see that low shank and super high shank feet have the same length but differ in height, so we can convert from one to the other by exchanging the presser bar. High shank feet on the other hand are also longer, so you would also need to reposition the presser bar to convert, which is beyond my capabilities.


When comparing feet, always make sure you use the primary zig-zag or straight stitch feet, not satin stitch feet as they often have a shorter shank to artificially decrease the foot pressure. On many machines however the pressure becomes too low and the machines fails to make stitches.

Preparing for conversion

So today I am converting my Frister+Rossmann 804 from super high shank foot fitting to low shank to match the rest of my machines.

The first thing to do is of course to establish that the foot fittings only vary in height, not in length, but we’ve done that already. Now we need to figure out what length presser bar we need, and then source it.

Difference in bar length

In case of converting from a higher shank foot to a lower one, the new presser bar needs to be longer than the old one by the difference in shank height. In our case, that’s 16mm.

Length of the old presser bar

​To measure the existing presser bar, we first need to expose it. The bottom end is of course in plain view, but the top may be obscured by pressure adjuster, and they come in different designs. The main difference is that some are hollow, so the exact length of the presser bar is not that important, as long as it is not too short. Others, however, have a closed end, so the presser bar has to be pretty much exactly of the right length for the system to work.​

Hollow pressure adjusters

If your pressure adjuster is hollow as in the left most photo, you can measure your current presser bar straight away. Then add or subtract the difference depending on your conversion, and the result is the minimal length for the new bar. A longer bar will be fine, it will simply poke at the top a bit more.

Closed top screw-in pressure adjusters

For adjusters with a closed top, you need to see where the presser bar ends. Many adjusters can simply be unscrewed and removed to expose the bar.

Measure the bar from the lower edge of the foot mounting hole to the top of the bar, then add or subtract the shank height difference depending on your conversion. We use this more involved method of measuring here because the length of the bit below the mounting hole is really not important, but we need an exact measurement. Your new bar must also be measured in this more precise manner.

Stubborn pressure adjusters

Some pressure adjusters are set in differently, so they don’t just unscrew. Such is the case with my Frister+Rossmann 804. Remove the side cover and find out how the pressure adjuster is kept in place, then loosen it – hopefully it’s just a screw.

You should now be able to remove the pressure adjuster, you may need to help it on its way out with some oil. If it is still stuck, it may be jammed by a splinter created by that positioning screw, as was the case with my machine. You can see it through the screw hole.

​​

So after some resistance, and trying hard not to damage rather delicate top of the adjuster, I finally managed to pry it out of its hole.

Ah, so now we can finally see the top end of the presser bar so we can measure it from the lower edge of the foot mounting screw hole to the top: 153mm. Adding the 16mm shank difference, my new bar should be 169mm long, not counting the bit below the foot mounting screw hole.

Finding a replacement presser bar

And that’s the hard bit! Where on Earth do you find another presser bar 16mm longer than the odd one you’ve got? Well, check your machines… Amazingly enough, shaft diameter of presser and needle bars is the same across a large number of makes, so the only kind of bar that you can’t have, is likely to be that of a Singer 12 on the account it being squared. I have listed a few bars with their lengths in a separate post.

Many machines will accept a two-part presser bar from a Singer 99. The lower part has the standard diameter and is hollow. The upper part has a smaller diameter and begins with a spring that is inserted into the lower part. 

You then put your usual large spring over the whole contraption.

 This adapts the bar length to whatever is needed, within reason. However, as the bar is no longer one solid stick, it does not work with some levers. You’ll need to try it out and see.

In the very worst case, you will have to get a longer bar and cut off the excess from the top. This may be easier said than done as those bars are really solid, but where there is a will, there is a way!

In my case I found that the high shank presser bar from Janome’s New Home 509 was only 3mm too long. It was worth a try!

Removing the old presser bar

Remove the spring or springs and rings, as some machines have several. The presser bar is fixed in position by a screw (or screws) in the presser bar lifter that sits on top of the foot lifting lever.

Loosen the screw(s) and rotate the presser by the foot or with a pair of pliers as it is likely to be stuck. Once it rotates freely, remove the foot and the foot mounting screw and slide the bar upwards and out through the top. Phew!

Inserting replacement bar

The new bar goes in the same way as the old one went out. If it seems to catch on something or get stuck along the way, polish it up with some fine sandpaper (grade 3,000 works well), lubricate it and if necessary tick it on the head with a hammer.

Aligning replacement bar

How far down should the new bar extend?

If your machine is straight stitch only or you have a straight stitch needle plate, install it and mount the main straight stitch foot on the new bar. If you only have a zig-zag needle plate, use the main zig-zag foot. Be sure to avoid satin stitch or other special feet.

Drop the feed dogs or rotate the balance wheel until the dogs are completely submerged. Lower the foot lifting lever and drop the presser bar so that the foot rests on the needle plate. Rotate the foot so that it is aligned with the feed dogs and the needle hole in the foot aligns precisely with the needle hole in the plate underneath.


This is it! Tighten the screw(s) in the bar lifter to secure the bar in position.

Re-assembling

Put the spring(s) back in through the top and fix the pressure adjuster. Cover back on and you are done! Congratulations.

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