Which Grit Emery Cord / Abrasive String

[friquant]

Which size emery cord is the most useful for needle holes in feed dogs, holes in take up lever, and other places along the thread path?

The reason for the question is economics. It costs $25 for a 50 foot roll of Mitchell's abrasive cord. But it comes in multiple diameters and grits. I'd rather not buy six rolls to find one I like.

Here are the sizes available on the mitchell website:

• 49 Abrasive Cord, .082″ (2.1mm) Diameter, 120 Aluminum Oxide grit
• 50 Abrasive Cord, .070″ (1.8mm) Diameter, 180 Aluminum Oxide grit
• 52 Abrasive Cord, .055″ (1.4mm) Diameter, 150 Aluminum Oxide grit
• 52-C Crocus Cord, .055″ (1.4mm) Diameter, Used to polish metal, Leaves ultra-fine finish
• 53 Abrasive Cord, .040″ (1.0mm) Diameter, 180 Aluminum Oxide grit
• 54 Abrasive Cord, .030″ (0.8mm) Diameter, 180 Aluminum Oxide grit
• 55-S Abrasive Cord, .018″ (0.5mm) Diameter, 200 Silicon Carbide grit

 

@gottaknow showed a photo of a machine he worked on with #49, which is 120 aluminum oxide grit : 

https://leatherworker.net/forum/topic/63222-adler-467-for-venator/#findComment-409711

Note the coarser grits tend to come on larger diameter cord. While pondering this important question, I found and purchased a used two pack on ebay ($13 after taxes and shipping) to try out. 

Of these two, I like No. 50 (180 aluminum oxide grit) the best. These are not in prime condition. The No. 55 breaks easily and the No. 50 loses its grit faster than I would like. (also less flexible than I would like but not sure if new material is more supple)

This is the feed dog I was smoothing out today.

I accidentally sharpened the inside edge (overshoot!) Sometimes I'm at the mercy of what angle will actually allow me to pull it through. (Thick cord gets stuck easily in narrow openings)

 

Previous to this month, I was using ordinary sheets of paper-backed sandpaper. I would cut a skinny strip and run it through whatever orifice needed it. But the paper shredded easily which required multiple attempts. The same week I bought the two-pack of emery cord on ebay, I also bought these rolls of 2.5cm (1-inch) emery cloth in varying grits. So this represent my current arsenal: 

What grits are you using? Do you get by with emery cloth alone, or do you use emery cord/ string? 

@TinkerTailor may he rest in peace says you can make your own emery string: 

https://leatherworker.net/forum/topic/72973-thread-lube/#findComment-478572

 

 

 

[bruce johnson]

I am not using these on sewing machines anymore, but I do use the abrasive cords and tapes almost daily refurbishing bench machines and tools. 

My current abrasive lineup is
#49
#51-S
#52

My polishing lineup is
#52-C round
#56-C flat tape

I have had other grits but these are the currents and I can do about whatever I need to with them. I buy them in 25 foot rolls and with that - they last a long time. The Mitchell website is pretty weak, but if you google you can find them on Amazon, guitar maker suppliers, machinist suppliers, and more. They have more range of grits and abrasive materials and spool sizes. Some of them put up a variety pack kit too.

[BUS]

10 minutes ago, bruce johnson said:

I am not using these on sewing machines anymore, but I do use the abrasive cords and tapes almost daily refurbishing bench machines and tools. 

My current abrasive lineup is
#49
#51-S
#52

My polishing lineup is
#52-C round
#56-C flat tape

I have had other grits but these are the currents and I can do about whatever I need to with them. I buy them in 25 foot rolls and with that - they last a long time. The Mitchell website is pretty weak, but if you google you can find them on Amazon, guitar maker suppliers, machinist suppliers, and more. They have more range of grits and abrasive materials and spool sizes. Some of them put up a variety pack kit too.

Seems perfect for edge bevelers and such? I never knew this existed. 🤣

[CowboyBob]

We like the #52 for sewing machines.

[friquant]

1 hour ago, CowboyBob said:

We like the #52 for sewing machines.

Do you find it helpful to polish afterwards, or is it left smooth enough as is?

[CowboyBob]

17 hours ago, friquant said:

Do you find it helpful to polish afterwards, or is it left smooth enough as is?

It smooths it w/o polishing.We use it on a feed dog,needle bar thread guides,needle hole in needle plates.

[alfredleatherworks]

This is really great info, and a product I wasn’t aware of before. Thanks, y’all!

[friquant]

I bought a new roll of #52. The grit sloughs off quickly, and the yarn (inner core) it's glued to breaks easily. It not all that flexible either. The lack of flexibility limits the exact path you can run with it. Once the grit has sloughed off, it's more flexible. But by then it's not grinding much and pretty soon after that it breaks. 

I've started being more particular about how I approach smoothing out a hole. (This because I made a mess of a feed dog grinding too much away with the #50 old stock.) Sometimes I go straight out one end so that the other end can take advantage of whatever curve the emery string can bend to. And I have a good look with a loupe (or floss the hole with sewing thread) to check progress after each piece of emery string breaks. And I'm paying attention to work evenly around the whole opening so it doesn't cut a groove on one side. Who knew there was a learning curve!?