SDS vs. SDS Plus vs. SDS Max vs. Spline Drive

There is sometimes a little confusion as to what bits work with which tools and what the best bits to use with each job are. It is a little confusing, even for us who are constantly using these different acronyms. It was much simpler before when there was just SDS with smaller bits and Spline Drive for the larger heavy duty stuff. Later there was the introduction of the SDS-Plus which does work interchangeably with regular SDS bit and simply offered a stronger connection, so not much confusion there. Then however we got the SDS Max which is not compatible with anything else and is very similar to Spline Drive for strength and capacity.

If you are starting with an empty toolcrib I can tell you the trend for most manufacturers and buys is going towards the SDS Max over the Spline Drive. Although some people with existing bits and equipment are holding true to the Spline Drives so it would be hard to imagine either style going away anytime soon.

SDS & SDS Plus – Typically used with Carbide drill bits 5/32” – 1-1/8” and thin wall carbide core bits up to 4”. There are also several types of smaller chipping and chiseling bits that work extremely well with standard SDS Rotary Hammers. You will find the tools often give max capacity right in the title such as 1” SDS or 1-1/8” SDS. These are solid bit capacities so don’t go sticking a 1-1/8” bit on a ¾” SDS Rotary Hammer Drill, even though the bit will fit it is going to be under powered.

SDS Max – Typically used with Carbide drill bits 1/2” – 2” and thick wall carbide core bits up to 4” (thin wall up to 6”). There are also many chipping, chiseling, bushing, cutting and digging bits that work well with the SDS Max tools. Many of the demolition tools and large breakers will use the Hex shank but that is another topic for another day.

Spline Drive – Typically used with Carbide drill bits 1/2” – 2” and thick wall carbide core bits up to 4” (thin wall up to 6”). There are also many chipping, chiseling, bushing, cutting and digging bits that work well with the SDS Max tools. Most of the time the SDS Max & Spline drive tools are identical with simply different chuck retainers to distinguish the different models.

Adaptors – You can get adaptors to go from SDS Max to Spline or vise-versa or from either size down to the smaller SDS or SDS Plus sizes. It is obviously best to avoid unnecessary adaptors whenever possible, just another thing to loose, break, etc. I don’t think there are any adaptors available to go up from SDS to the larger sizes (SDS Max or Spline) and if there were such an adaptor it would be best not to use it.     

SDS = SDS Plus
SDS Max = adaptor for SDS & SDS Plus, Adaptor for Spline
Spline = adaptor for SDS & SDS Plus, Adaptor for SDS Max  

One point that probably causes the most confusion of the different style bits is the tool capacity rating in the titles. For instance a Bosch has a few SDS-Plus Bulldogs; one is a 7/8” SDS-Plus & the other is a 1” SDS-Plus. This inch rating refers to the drilling diameter capacity or basic power of the drill not a different size SDS-Plus shanks; all SDS-Plus shanks are the same.

Another point of confusion is there are two types of larger hammers produced by most manufacturers the demolition hammers as well as rotary drill hammers. The rotary drills can almost always be used as a drill and also switched to only hammer mode for using chisels. These are also sometimes called combination drills. The demolition hammers on the other hand only operate in hammer mode and can’t drill which means they are significantly cheaper. When shopping online sometimes the pictures might be the same, make sure you are getting the right unit.  

If you have any questions at all about any SDS tools or accessories please call the experts at Ohio Power Tool 800-242-4424 or email In addition to knowledgeable sales staff they also are also running a winter/early spring special on all SDS, SDS Max & Spline Drive Carbide Hammer Drill Bits for 50% off list price. Stock up now and save considerably. Search Tools by Category: SDS & SDS Plus Hammer Drills, SDS Max Hammer Drills, Spline Drive Hammer Drills.   



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  1. bob says:

    What is the SDS-Top? I found nothing on this in the article above.

  2. Jay A says:

    Everyone else uses these standards… and then there is Hilti who makes up their own bits & standards. Unfortunately if you have a Hilti hammer you are pretty much stuck paying the Hilti inflated prices for bits as well.

  3. Pingback: Bosch to Reclaim Title of Hardest Hitting Rotary Hammer with RH540M / RH540S |

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