Why do reciprocating saw attachments have the fancy tangs?

[jimjdm]

Reciprocating saws have attachments with a complex tang shape as shown below

I had to disassemble a Milwaukee sawzall blade holder recently, and I noticed that it appeared a simple rectangular shape behind the hole would fit. I tried making a plain rectangular tang, and it fit without any issues. I found a link to an old patent from 1961 at https://patents.google.com/patent/US2987086A/en that shows a complex universal tang that is similar to the one in the attached picture. Are there modern tools that need the special tang, or is it some historical artifact?

 

[kmacht]

Leverage.

 

[Firebrick43]

The manufactures don’t make much on selling you the saw, some even sell the saw at cost. Many times more is made on selling replacement blades and they would be pleased if you bought those blades from them instead of another company.

And what better way to encourage you to do so?

Of course Milwaukee became the de facto standard so many reciprocating saws matched the pattern after their patent expired a long time ago.

Also the little *** on the back “MAY” be for something that you don’t even think about, such as to hold the blade in a fixture when it’s heat treated so as to not affect any part that heat treating is needed

 

[RTM]

Don’t have to loosen the screw as much to get the small *** in, vs getting a full square in there?

 

[jimjdm]

Leverage.

Also the little *** on the back “MAY” be for something that you don’t even think about, such as to hold the blade in a fixture when it’s heat treated so as to not affect any part that heat treating is needed

The tang I made that fit OK was a rectangular for the full length of the tang like in the first blade below.


That would have more support and could probably be held just as well for any processing. And it would be simpler to make, which still leaves me wondering why the complicated shape is used.

 

[jimjdm]

Don’t have to loosen the screw as much to get the small *** in, vs getting a full square in there?

You still have to loosen it the same amount to get past the metal behind the hole. Maybe it could be loosened for a shorter time, but how does that help anything?

 

[WWheeler]

Although the shoe on every recip saw I've used allows for the blade to be flipped either way, I've always assumed the tang on most blades is like that to allow for a tool designer to make a shoe that would allow it to fit in only one direction, perhaps for better safety.

 

[Firebrick43]

The tang I made that fit OK was a rectangular for the full length of the tang like in the first blade below.


That would have more support and could probably be held just as well for any processing. And it would be simpler to make, which still leaves me wondering why the complicated shape is used.

They are stamped so the shape can be complicated as they want and in the scheme of things the complexity of the shape is inconsequential

And I have seen small little **** to hold parts in heat treatment. It’s more about the holder conducting heat away from the part. Smaller cross section means less conduction.

 

[jimjdm]

They are stamped so the shape can be complicated as they want and in the scheme of things the complexity of the shape is inconsequential

And I have seen small little **** to hold parts in heat treatment. It’s more about the holder conducting heat away from the part. Smaller cross section means less conduction.

All else being equal, simpler is generally better, although the argument for facilitating heat treating seems reasonable. I expect that a good percentage of the attachments would get some type of heat treatment.

 

[bassJAM]

The tang is for strength, and it's only needed in that location since that's where for force is being applied while you're cutting.

The reason for the tang instead of a filled out rectangle is most likely a cost-savings. When you're stamping millions of these blades, being able to save a few grams of steel on each blade adds up. Cutting the tang that way lets the manufacture save 1/4" of material or so on every blade they make, they probably stamp them in a pattern something like this:

 

[neophyte]

The tang tooth adds extra leverage, as has been mentioned.
If you look at the pic in this post, you can also see how the blade tang design allows the blade manufacturers to save a bit of steel, since the tang is skinny, and can be punched out of the back of a mirror imaged saw blade.
This saves maybe an inch of steel length per blade, which might only be worth a penny, but pennies add up when a manufacturer is producing tens of millions of saw blades a year.
The tapering tip of the saw blades also saves steel with certain blade designs.
The long finger also lengthens the blade, which would reduce wiggle in the saw blade arbor, which would reduce wear on the saw blade arbor, particularly the modern quick release arbor that tend not to hold blades as solidly.
Another reason for the design may actually be to add potential shock absorption.
Cutting thru a soft material like construction lumber, then running into a hardened nail would jar would jar the blade, potentially leading to blade damage, or damage to the reciprocating saw blade arbor.
The skinnier tang would flex more that a wider tang, potentially preventing damage. Bosch T-shank jigsaw blades have a skinnier neck between the T-Shank arbor, and the toothed section, although I have no clue whether this was integral to the blade engineering.