TechSew 5100 -- metal piece sheared right off!

[SewMuchToLearn]

I was just starting to sew on my TechSew 5100 this afternoon -- I had literally taken 2 stitches -- when a piece of metal flew out of the bobbin area. The piece had completely sheared off. Has anyone had this happen before? I bought the machine new from TechSew about 6 months ago and have used it lightly since then, probably only an hour or two a month, so I'm surprised.  I assume it's a (major!) manufacturing defect in the machine.

I emailed their support for help (they are closed for the weekend.) @Techsew Ron 

Has anyone had something like this happen?  Any tips to avoid this in the future? 

Edited September 16, 2022 by SewMuchToLearn

[suzelle]

https://www.techsew.com/en/techsew-5100-4100-shuttle-hook.html

I'm sure Techsew will want to take care of that for you very soon. At least I hope they will. You probably found the part already, but here's the link to what I found on their site. Techsew was one of the machines I was considering when I get a cylinder arm. I'm wondering now what the material is they make that hook out of and where it's manufactured. Also wondering what your options are for quality. Can another brand be purchased like Cerliani??? Just a thought.

[Wizcrafts]

WOW! That was your hook driver!

[kgg]

2 hours ago, SewMuchToLearn said:

Has anyone had something like this happen?

 

1 hour ago, Wizcrafts said:

WOW! That was your hook driver!

Like Wizcraft all I can say is holy shit, I have never see that one before. This would be a good example of what damage a safety clutch can prevent in the sub 441 class machines. Looking at the photo's I would also check everything associated with the driving of the bobbin assembly all the way back to the main drive.

1 hour ago, suzelle said:

I'm wondering now what the material is they make that hook out of and where it's manufactured.

Like most machines these days it's probably made in China or Taiwan (Republic of China).

kgg

Edited September 16, 2022 by kgg
added words

[dikman]

 That is impressive! It must have been fractured when fitted, I don't see how you could do that otherwise.

A bit of JBWELD? Just kidding.

Edited September 16, 2022 by dikman

[RockyAussie]

I have never seen that before. I wonder if something was too tight or jamming the hook from turning like something in the hook race? One of the reasons I like to have those spring screws out 1.5 turns I guess. OIL should happen on the hook race ever hour of use by my reckoning as well. I am sure that Ron will help you out.

[Northmount]

When you look closely at the fracture you see what appears to be crystals.  From my limited knowledge of metallurgy, this is brittle fracture.  Here is some authoritative information if you want to study it a bit more.  https://www.corrosionpedia.com/definition/280/cleavage-fracture

Quoted from above article:

Cleavage fracture surfaces appear in steels due to:

• Sudden or impact loading
• Low temperature
• High levels of constraint
• Ambient temperature
• Heavily cold-worked parts

I think the last item in the list is probably the root cause.  If it was the first item in the list, I would expect to see a lot more damage, likely in the drive train.  That is my guess, and am willing to stand corrected if there is a knowledgeable metallurgist here in the forum.

[Burkhardt]

46 minutes ago, Northmount said:

When you look closely at the fracture you see what appears to be crystals.  From my limited knowledge of metallurgy, this is brittle fracture.  Here is some authoritative information if you want to study it a bit more.  https://www.corrosionpedia.com/definition/280/cleavage-fracture

Quoted from above article:

Cleavage fracture surfaces appear in steels due to:

• Sudden or impact loading
• Low temperature
• High levels of constraint
• Ambient temperature
• Heavily cold-worked parts

I think the last item in the list is probably the root cause.  If it was the first item in the list, I would expect to see a lot more damage, likely in the drive train.  That is my guess, and am willing to stand corrected if there is a knowledgeable metallurgist here in the forum.

Looks to me in the pictures the dark spots in the broken area it has been failing for awhile probably a bad casting from the get go. The crack probably started when they machined it.

[Northmount]

13 hours ago, Burkhardt said:

Looks to me in the pictures the dark spots in the broken area it has been failing for awhile probably a bad casting from the get go. The crack probably started when they machined it.

Yes, the discontinuities in the crystal structure pretty much says bad casting and mill work.

 

[MikeRock]

What looks like a dark groove in photo Nr. 1......is that groove worn in there since purchase or is it designed in?  It 'looks' like that worn area and its mating surface might have seized up or at least had very high friction loading.

Looks like some shrinkage cavities in the dark area. 

Did the needle survive?