BOSCH HC4021 5/8 In. x 13 In. Spline Speed-X Rotary Hammer Bit for Concrete Drilling

Bought it to drill into concrete and it works amazingly!

Roto hammer bit doesn’t bind up.

worked great!

Cut through concrete fast and easy. Drilled nice and straight. I hit 1/2” rebar on 2 Nd hole (12” deep). Bit went through. That dulled the tip, but the bit kept going( slower). Went through rebar on 3 rd hole. Drilled 4 th hole nice and smooth but slower then first.

This is my second purchase. The first drilled over 300 holes through 24" limestone blocks and 12" into the block under them before the top twisted off. Very impressive.

Bought the last Bosch model rotary hammer/drills at half price. Didn't know if this new star shaped holder end would work in that older model tool. It does and does just as well as the older hex receiver end bits. Used to drill holes in old foundation for demo with expensive motar. Older guys couldn't believe that I didn't need a jack-hammer.Word of caution: Occassionally, lift hammer while drilling to clear dust out of hole or drill will stuck. You may need a second bit and leave the stuck bit in the hole until the next morning when the expensive mortar has cracked the concrete or whatever you're drilling. When you're using young help, they're not going to do what you tell them to do until they get into trouble-and even after that maybe.

First off - any review that doesn't understand that any spline bit had 5" that is not usable means that person doesn't understand spline or SDS Max bits. (That's how they come - all of them!)I used a 1 9/16" Bosch spline rotary hammer with this bit and it ate through rock with ease. I was able to consecutively drill 5 holes 5" deep without the bit overheating - three times in an hour. Be sure to clear the dust every so often to keep the bit from binding - like you should with any bit. Like I've seen on tool box buzz, I find the Bosch bits to outperform DeWalt, both in speed and durability.

I've always like Bosch because of its high quality & made in europe other than china. I compared Bosch's price & quality with others like DeWalt. To my surprise, DeWalt's price was too high thru Amazon. I needed a concrete drill bit to drill a hole thru my basement walls to rearrange my plumbing. This Bosch rotary hammer bit is the best there is, for spline line. I've looked everywhere and I've compared the prices & quality even against Bosch's regular Bosch rotary hammer bit. I will tell you, it's worth it to pay couple more bucks to get the "wild bore" because it will dig into the wall much better, with 4 cutters instead of 2. Can't go wrong with this product.

I did a bit of research to find parts for my older Hitachi rotary hammer, and this one was indicated. By the time I ordered, it was on clearance , even. Works as well an expected in the rotary hammer. Shipping was decent, packaging a bit larger than expected, but well protected. These things are getting harder to find, so get 'en while you can

La photographie partielle de l’article ne montrait bas la prise de la mèche «  spline » qui ne correspond pas à ce que j’ai besoin. Je ne connaissais pas ce qualificatif pour les mèches à béton. C’est pour celà que je suis déçu. Y a-t-il moyen de retourner l’article? Merci.

Broke the carbide bits off the first time and quad ends are suppose to be longer lasting then just the normal 2 carbides

Seems to work great. The dewalt bit might be a little stronger, but they are hard to find.

Shape did not match the picture.Bought for an extruder project so will see.