There is sometimes a little confusion as to what bits work with which hammer drills and what bit is best for each job. In the beginning there were a ton of different styles of hex and tapper bits, lots of manufacturer had their own, we won’t even get into that. Spline was introduced here in the US as a universal shank everyone could use, around the same time SDS bits started being introduced from Europe (Hilti & Bosch) which allowed the bits to be locked into place better but still move up and down.
Later the SDS-Plus was introduced to improve upon SDS which works interchangeably with regular SDS and simply offered a better connection. Spline was a good solution for the larger bits but then the SDS-Max was introduced which was supposed to replace Spline Drive for larger drills, with equal strength and capacity but improved connectivity similar to the smaller SDS bits. While SDS-Max has caught on it unfortunately never replaced Spline and now we have both types of tools and bits on the market for really no good reason we can see.
If you are starting with an empty toolcrib we would recommend going SDS-Max over Spline, there are several more options in accessories and eventually everything might go this way. The reason we still have both is because folks 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.
Strait Shank – These are the carbide drill bits you would use in a chucked hammer drill (which are mostly not “rotary hammer drills”). Typical size of carbide bits available is 1/8″ – 1″ but we don’t normally recommend this style over 1/2″ unless you just have a few holes to drill. The chuck hammer drills doesn’t allow in/out movement of the bit and are often less powerful but with a much higher impacts per minute rating.
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-Plus or 1-1/8” SDS-Plus. These are solid carbide bit capacities so while a 1-1/8” bit will fit in a ¾” SDS-Plus Rotary Hammer Drill, it is not recommended and it will 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 use the SDS-Max bits while ever larger units 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 Spline tools. Most of the time the SDS Max & Spline drive tools are pretty much identical with simply different retainer chucks. The selection on tools and bits will be slightly less for spline drive but remains very common. The one big difference with a spline system is that the shanks for drilling and chisel bits looks considerably different. For the chisel bits the shank which is not intended to spine is smooth (so no splines) and the part below is flat.
Hammer Drill Adapters – You can get adapters 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 best to avoid unnecessary adapters whenever possible, just another thing to loose, break, etc. There are not any adapters available to go up from the smaller SDS-Plus drills to the larger sizes (SDS Max or Spline) and if there were such an adapter it would not be recommended to use.
SDS = SDS Plus
SDS Max = adapter for SDS-Plus, Adapter for Spline
Spline = adapter for SDS-Plus, Adapter for SDS-Max
The most common point of confusion is the different tool capacity rating in the titles. For instance Bosch has a couple SDS-Plus Bulldogs; one is a 1” SDS-Plus & the other is a 1-1/8” SDS-Plus. This inch rating refers to the solid drilling diameter capacity or basic power of the drill, not a different size SDS-Plus shanks. All SDS-Plus shanks are the same, just as all SDS-Max and Spline are the same size.
Another point of confusion for the tools is with the two types of larger hammers produced, the demolition hammers vs rotary drill hammers. The rotary drills can be used as a drill and most of the time can be switched to a hammer only mode for using breaker 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 often cheaper with less parts to fail if you just want to use them for strictly demo purposes. When shopping online sometimes the pictures might be the same, often the differences are internal, make sure you are getting the right unit.
If you have any questions at all about any Rotary hammer drills or carbide accessories please call the experts at Ohio Power Tool 800-242-4424. They would be more than happy to address any questions or talk more in-depth about related topics such as Hammer Drill Core Bits vs Diamond Core bits or any concrete tools.