Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.

--
AnthonyL

Why ever wait to finish a job before starting the next?

On 18/11/2020 13:44, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.

Is it completely soft? In which case it is presumably a rubbery polymer
heavily loaded with iron oxide and then magnetised. You could use a
file, or sandpaper, or even perhaps a stanley knife.

The problem might be if it has small rare earth magnets embedded in it,
and these won't be so easy to trim. Should be easy to tell by exploring
with something like iron filings or small tacks. The magnetic "hot
spots" will be obvious.

On Wed, 18 Nov 2020 15:14:36 +0000, newshound
wrote:

On 18/11/2020 13:44, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.

Is it completely soft? In which case it is presumably a rubbery polymer
heavily loaded with iron oxide and then magnetised. You could use a
file, or sandpaper, or even perhaps a stanley knife.


Yes, it's a slab as per the ebay picture of about 4" x 1.25" x .125"
thick, evenly magnetised. There seems to be very little on the
internet that I can find but yes it is a rubbery polymer as far as I
understand, and the magnetism is even across it's surface.

So just treat it as plastic then seems to be the order of the day.

The problem might be if it has small rare earth magnets embedded in it,
and these won't be so easy to trim. Should be easy to tell by exploring
with something like iron filings or small tacks. The magnetic "hot
spots" will be obvious.


--
AnthonyL

Why ever wait to finish a job before starting the next?

On 18/11/2020 13:44, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.


It's an expensive way to buy a strip of eg...

https://www.ebay.co.uk/itm/Premium-S...gAAOSwsbhd-KpF

....but cutting it won't matter, except you'll lose the magnetism from
that part. It's actually a Halbach array which in this case is used so
as to make a weak magnet just about strong enough.

--
Cheers
Clive

On Wed, 18 Nov 2020 17:45:29 +0000, Clive Arthur
wrote:

On 18/11/2020 13:44, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.


It's an expensive way to buy a strip of eg...

https://www.ebay.co.uk/itm/Premium-S...gAAOSwsbhd-KpF


SWMBO, but it is also too rigid to be called tape even if it is a bit
flexible..

...but cutting it won't matter, except you'll lose the magnetism from
that part. It's actually a Halbach array which in this case is used so
as to make a weak magnet just about strong enough.


I was curious as to why I could not use another, smaller, polymer
magnet to put against it and get them to repel, sort of one to "float"
above the other.


--
AnthonyL

Why ever wait to finish a job before starting the next?

On Wednesday, 18 November 2020 at 13:44:26 UTC, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.

Has she not got a foot that guides seams?

How about, instead of removing some of the material, add some! Imagine sticking on a layer, or two, or three, of something like insulation or masking tape over part of the magnetic guide. Whatever is needed to clear the feed dogs.

Unless the direction of the magnetic field matters its cutable. I have some
of that floppy stuff which are offcuts from bigger signs etc, and you can
cut those with scissors and they still remain magnetic.. I think its some
kind of powder.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"AnthonyL" wrote in message
...
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.

--
AnthonyL

Why ever wait to finish a job before starting the next?

On 18/11/2020 18:43, AnthonyL wrote:
On Wed, 18 Nov 2020 17:45:29 +0000, Clive Arthur
wrote:

On 18/11/2020 13:44, AnthonyL wrote:
Are there any downsided to cutting (scalloping) a small piece out of a
soft magnet?

My wife bought a magnetic seam guide as per

https://www.ebay.co.uk/itm/202976712124

The problem is on her machine when she is doing a close seam (1/4")
the guide sits on the feed dogs and if I took out just a little
material it would sit nicely.

I'm looking at about 1mm depth for about 25mm length and 10mm width to
clear the feed dogs and was going to use a metal file unless someone
has a better idea.


It's an expensive way to buy a strip of eg...

https://www.ebay.co.uk/itm/Premium-S...gAAOSwsbhd-KpF


SWMBO, but it is also too rigid to be called tape even if it is a bit
flexible..

Self-adhesive, stuck to a bit of card or plastic.

...but cutting it won't matter, except you'll lose the magnetism from
that part. It's actually a Halbach array which in this case is used so
as to make a weak magnet just about strong enough.


I was curious as to why I could not use another, smaller, polymer
magnet to put against it and get them to repel, sort of one to "float"
above the other.

They have alternating north and south poles in 'stripes' with a pitch of
maybe a couple of millimetres or so. If you take two identical ones,
faces together, you'll find that they 'cog' as you slide one past the
other, as the multiple poles line up to attract then repel.

The back side has very little external field by design - that's what a
Halbach array does, it pushes most of the field out one side.

--
Cheers
Clive