Slipjoint question, is this normal?

Hengelo_77

Hengelo_77

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Mar 2, 2006
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When the tang of the blade rubs on the spring it makes these marks. Is that normal?
I've rounded the corners and finished them up to 2500grit and buffed lightly. I also put lithium grease on there.

20241130-100444.jpg
 
What happened to the photos?

Only thing I'm mention is ideally the mark should be the full width of the backspring. When the mark is only half of backspring, that indicates the tang and backspring are not matching flat across the full width.
 
Ken H> said:
What happened to the photos?

Only thing I'm mention is ideally the mark should be the full width of the backspring. When the mark is only half of backspring, that indicates the tang and backspring are not matching flat across the full width.
Click to expand...
Can you see the pics now?

The spring is 0.2mm wider then the tang, it runs betwee two 0,1mm bronce washers. It looks to me as if the full widh of the tang runs on the spring
 
Yep photos showing nicely now. They were showing for me at start, just not when I posted - might be on my end causing pics not to show if everybody elese was seeing them.

OK, with backspring wider than blade the mark wouldn't be across the total backspring.
 
SBuzek said:
That is not normal, you are leaving small burs on the radius of the tangs and that is acting like a file and digging gouges in the spring.
Yes a spring will burnish but should not have metal removed.
Click to expand...

What is the best way to remove these burs, buffing?
 
Hengelo_77 said:
What is the best way to remove these burs, buffing?
Click to expand...
No, best way is by hand with 400 grit paper.
Run you fingernail around the radius, you can usually feel them.
The best way to not create them is to make consistent passes all the way around the radius as they form where you start and stop.
 
Last edited:
SBuzek said:
No, best way is by hand with 400 grit paper.
Run you fingernail around the radius, you can usually feel them.
The best way to not create them is to make consistent passes all the way around the radius as they form where you start and stop.
Click to expand...

When I finish those corners I start at 400 grit and go up to 2500. Is that good or do I go to fine?
 
Hengelo_77 said:
When I finish those corners I start at 400 grit and go up to 2500. Is that good or do I go to fine?
Click to expand...
To me, that's too high. I usually finish to 400 or mabe 600.
Even though you are polishing the radius the bur is still there.
If you start to rotate the blade and it catches and starts to drag that is where the bur is.
 
SBuzek said:
To me, that's too high. I usually finish to 400 or mabe 600.
Even though you are polishing the radius the bur is still there.
If you start to rotate the blade and it catches and starts to drag that is where the bur is.
Click to expand...
Thnx, so 400/600 for the tang.
What grit size do you finish the touching part of the spring?
 
Hengelo_77 said:
Thnx, so 400/600 for the tang.
What grit size do you finish the touching part of the spring?
Click to expand...
Also 4-600 same direction as the tang.
Also if you start to rotate the blade and it starts to dig, stop right there before you dig a chunk out of your spring because then it has to be resanded to 400 grit before continuing.
 
I would agree that amount of galling and digging into your springs is not normal.

Lots of good advice here but I would ask you what hardness your drawing your springs and blade tangs back to after hardening?

I would draw my springs back to 46 +- Rockwell C. Blade and tangs 58 to 60 C.

Point being that if spring is too soft you risk galling and upsetting much more, too hard you risk broken back springs.

I would finish my springs where they rode on the blade tang to 600 grit length wise. The blade tang I would finish to a very used 600 grit belt on my horizontal 2 x 72 grinder and then finished up by very lightly using green rouge on a firm sewn cotton buff to break the sharp edges and give the radius of the tang a bright finish. Lightly is the key word.
 
ken erickson said:
I would agree that amount of galling and digging into your springs is not normal.

Lots of good advice here but I would ask you what hardness your drawing your springs and blade tangs back to after hardening?

I would draw my springs back to 46 +- Rockwell C. Blade and tangs 58 to 60 C.

Point being that if spring is too soft you risk galling and upsetting much more, too hard you risk broken back springs.

I would finish my springs where they rode on the blade tang to 600 grit length wise. The blade tang I would finish to a very used 600 grit belt on my horizontal 2 x 72 grinder and then finished up by very lightly using green
rouge on a firm sewn cotton buff to break the sharp edges and give the radius of the tang a bright finish. Lightly is the key word.
Click to expand...

I outsource HT, the spring came back 43 hrc, the blade 60hrc.
Would that be to soft and the problem?
 
That's a little soft, but looking at the original picture the way it is cut is not a too soft problem
Too soft and the spring will deform and dish but will do so smoothly.
 
Hengelo_77 said:
I outsource HT, the spring came back 43 hrc, the blade 60hrc.
Would that be to soft and the problem?
Click to expand...
Softer than I preferred but depending on all other fitting points and the amount of preload you maybe ok.

Are you confident that the edges of the tang and spring are 90 degrees to the flats? If so, try the tang radius and spring finishing advice given to see if that helps. Stan gave some really good advice, if digging in or galling, stop and start with new flat square surface on spring.
 
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