SDS versus SDS Plus Confusion

[qlopp]

Hi, this is just for the sake of conversation as it doesn't *really* matter, but I was confused by the concept of the (supposedly) original SDS chuck specification versus the SDS Plus or SDS+ spec which all bits seem to be made to now. The reason this confusion came up is that I bought a "SDS" rotary hammer from HF yesterday for an upcoming project, and found it odd they uniformly referred to it "SDS" rather than "SDS Plus" in all paperwork, advertisements, and packaging.

The specific model I purchased was the Bauer 1641E-B (HF #64288).

As a newbie I can't post links, but here is the general gist:

W W W harborfreight DOT com/1-18-in-sds-variable-speed-pro-rotary-hammer-kit-64288.html

The SDS Plus bits I have fit into the chuck and are free to stroke inward/outward but they don't rotate, pretty much as I had expected them to function. I'm curious if the unique cuts that qualify a bit's shank as "SDS Plus" offer some additional articulation to this basic in/out stroke if used in an SDS Plus chuck. Or is this all that SDS Plus bits in an SDS Plus chuck do? Keep in mind, for all I know this tool *has* an SDS Plus chuck and they just don't specify it due to legal or other reasons.

I guess I had conceptualized the difference in SDS Plus to have something to do with allowing some sort of limited rotation during hammering or hammer drilling, perhaps to increase shank life or reduce chuck wear, kind of like valve rotators on an OHV engine.

Does anyone know if the chuck design really matters between the two designations, or is it just the bit design, and if so, what is the improvement supposed to be in SDS Plus? I've Googled this extensively and can't find an answer.

 

[strength_and_power]

The selector switch to change it from drill to hammer, what position is it in?


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[dutchgray]

All the drills you see today that are known as SDS are actually SDS plus, I'm not aware of anything still using the original SDS spec, infact I dont think I have ever seen a plain SDS drill or bit. SDS plus is effectively the standard.
SDS max is the bigger stronger version that you get drill bits up to 2" or so and much heavier drills, as well much more impact energy.

 

[Al Borland]

Typically, you will see "SDS Plus' or the larger "SDS Max"
Some will rotate, hammer, or a combination of both depending on the setting of the selector.

 

[ttpete]

The selector switch to change it from drill to hammer, what position is it in?

Yup. RTFM........

 

[qlopp]

The selector switch to change it from drill to hammer, what position is it in?


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I assume you don't understand my question. I understand how to operate the tool. I already have/use a SDS Max rotary hammer. I was asking about the bit's articulation with respect to the chuck. Yes, the entire chuck spins when in drill mode and doesn't spin when in hammer mode. What does an SDS Plus bit do inside the chuck that an SDS bit doesn't?

 

[qlopp]

Yup. RTFM........

I did. Were you posting that helpful tip for someone else?

 

[qlopp]

To simplify, did the old SDS standard use a different chuck design than the new ubiquitous SDS Plus standard? Or is the difference only in the bit shanks? What does the difference accomplish?

 

[PBCampbell]

SDS plus has been around so long I can't even find an illustration of the original SDS. The original SDS retention system had 2 flutes versus the 4 of SDS plus if I remember correctly. SDS bits will work in SDS plus chucks, but SDS plus bits would not work in original SDS chucks. I believe better bit retention was the purpose for SDS plus.

 

[qlopp]

SDS plus has been around so long I can't even find an illustration of the original SDS. The original SDS retention system had 2 flutes versus the 4 of SDS plus if I remember correctly. SDS bits will work in SDS plus chucks, but SDS plus bits would not work in original SDS chucks. I believe better bit retention was the purpose for SDS plus.

Thank you, that makes sense. I guess I'd need to see a patent white paper to try to decipher why the extra oval "flutes" or indentations make a functional difference or improve the original design. I could have sworn that I read something definitive on it once but now that I go searching all I come up with are basic explanations like "Max is bigger" no matter how I parse my search on SDS vs SDS Plus.

 

[MoonRise]

SDS was the 'original', back in the 1970s.

AFAIK, before that 'standard' even became all that popular/common, Bosch (and others) 'updated' the design/specs to SDS-Plus.

All you'll really find nowadays is the SDS-Plus stuff (tools and bits). If you somehow came across an 'original' SDS bit (from 1975? ), it should fit and work in the SDS-Plus chuck.

10mm shank diameter with two 'partial' recesses and two 'full' (open to the end of the shank) recesses on the bits. The partial recesses engage in the chuck and keep the bit from falling out/off until you release the chuck, and the 'open' slots allow the bit to hammer back-and-forth inside the chuck (for the hammer action, and that is why you have to grease the slots so that the bit can slide inside the chuck and not grind against the chuck's guts ).

SDS-Max has an 18mm shank diameter and a similar but not exactly the same slot and partial-groove system on the bits.

(and for further trivia, there is also an SDS-Top that is in-between the Plus and the Max stuff, but it never really caught on).

 

[rlitman]

...and for further trivia, there is also an SDS-Top that is in-between the Plus and the Max stuff, but it never really caught on...

I found out in another thread here that yeah, it actually did catch on, but not under the SDS branding. Hilti sells it.

 

[MoonRise]

I found out in another thread here that yeah, it actually did catch on, but not under the SDS branding. Hilti sells it.

All I see currently on the Hilti website is SDS-Plus (Hilti also calls it TE-C)

https://www.hilti.com/c/CLS_POWER_TOOLS_7124/CLS_ROTARY_HAMMERS_SDSPLUS_7124

and SDS-Max (Hilti also calls that TE-Y)

https://www.hilti.com/c/CLS_POWER_TOOLS_7124/CLS_ROTARY_HAMMERS_SDSMAX_7124

They 'other' big-boy bit/chuck system is the spline-drive one.

Hilti doesn't list any, Bosch does (two tools and spline-drive bits as well).


Discussion of drive types for masonry tools:

https://www.boschtools.com/us/en/more/news-and-extras/knowledge-center/story_03.html

Spline-drive hammers:

https://www.boschtools.com/us/en/boschtools-ocs/spline-hammers-25328-c/


Spline-drive bits:

https://www.boschtools.com/us/en/boschtools-ocs/spline-hammer-carbide-22572-c/

https://www.boschtools.com/us/en/boschtools-ocs/round-hex-spline-hammer-steel-22566-c/

 

[GRB]

We bought Bosch SDS Plus Rotary Hammers in the 1970s. They were already SDS Plus. Don't think I've ever seen a "regular" SDS tools.
If there were any tools made that were SDS but not SDS Plus, they are probably all long dead.

We cover the full range of tools with 1/2" Hammer Drill, SDS Plus, SDS Max, and 1-1/8" Hex on a work truck that keeps several hundred masonary bits on it.

 

[rlitman]

All I see currently on the Hilti website is SDS-Plus (Hilti also calls it TE-C)

and SDS-Max (Hilti also calls that TE-Y)...

Their medium sized tool is TE-T

 

[usdemt]

I for one am lost. What is the issue? The bit spins with the chuck. That's how a drill bit and chuck work. The hammer motion is independent.