4Z1 Handheld Core Drill

In the process of building our retirement home we have made so many purchases that I have not had time to write reviews for every item we've acquired. This coring drill is such an exceptional machine that I had to take a few minutes to share a few thoughts. First, we purchased this drill as a one time use machine. Since its cost and the cost of the bit were less than the cost of renting a machine and bit, we purchased rather than rented. For the price, I expected something that would do the job and then be somewhat worn out. How pleasantly surprised we were to receive a smooth, quiet, and powerful machine that performed really well. With little more than moderate pressure and a little patience, (10 minutes or so each), we had three 3 inch holes in 6" cured, fiber reinforced concrete with imbedded rebar. I have to think this drill would make the cut for industrial use. One niggling little thing - as others have reported, we too got a shower from the water hose. While the knob for the side grip handle had to have been tightened by King Kong, the screws holding the hose to its fittings were little more than hand tightened. We'll take half the blame for the shower because we had fair warning, but the people on the assembly line should really pay closer attention to this detail. It would take so little effort to avoid creating an unnecessary and annoying distraction from what is otherwise a really fine package. We took less than a minute to tighten the screws and all was well. We'd buy this drill again.

The CORE DRILL Model 4Z1 2-Speed Concrete Coring Drill is a powerful and reliable tool, ideal for heavy-duty concrete drilling. Its 2-speed motor offers great versatility, providing high torque for large diameter holes and fast performance for smaller ones. The ergonomic design and water-cooling system ensure smooth operation, while the safety clutch adds an extra layer of protection. Though slightly bulky, its performance and durability make it perfect for professional use. Overall, the 4Z1 is a top-notch drill for those seeking precision and efficiency in tough concrete jobs.

I thought about renting a drill and I am so glad I did not because first of all this drill was almost the same price as renting one, second of all, after I drilled two 2.5" holes 7 inches thick horizontally I am really glad I did not rent one because I would have had to rent it twice as long as I thought it would take. This drill does not cut slow compared to others but when you only cut holes every few years it takes longer than you think. I was tired after the first hole and after the second hole I had to wait a couple days before I felt like drilling the other small ones so just after a few holes this drill has paid for itself and now I own it. I caught a long bit on it a couple times and I was worried that the delay in the clutch would catch me off guard but six inches deep and bound up did not twist my arms or wrists like I thought it would. I am 5' 10" tall at a stout and strong 175 and I could handle the catch in this drill pretty good. I have not hit any re-bar and I have been told that that is what causes the most damage but I did bind this drill up pretty good and once I even bound it up by trying to untie the kinked water line with my left hand as my right hand took the entire force of the bit catching (didn't twist my right hand like I thought it would and was a long ways away from breaking my hand or wrist) I almost gave this 4 stars because the crappy plastic water connection that comes with this drill has to be replaced first thing with a brass one that won't leak. I had one on hand and if you don't care about water leaking then this drill is a great deal. If you do care about too much water in places you don't want then be prepared and buy a garden hose adapter made out of brass and replace the one this drill comes with before you start drilling . all in all 5 stars.

So far we've drilled about a dozen holes with this drill. Nothing to complain about given the price. Although not recommended we've had no problems using this without a stand to drill 4" holes... however we do create a "starter hole" with a different bit on our hammer drill. I wasn't able to start the hole with the bit alone, it just skated away. The bubble level on top is extremely useful to keep it straight and level, we're coring cement decks for swimming pool rails and setting these level and plumb is very important. When using it handheld there's a tendency to lean forward and the bubble level keeps you on track if you watch it. We also bought the bluerock coring bit, that we haven't had as much luck with, it's already broken a tooth.

100x better than the steel dragon tools drill. the switch can lock but doesn't occur automatically like the sdt drill. plus it has a slower speed for larger bits. I bought this after drilling about 10 holes in 22" thick PA farmhouse walls with the SDT drill. Everything was going OK until the bit bound up on me recently and the drill body spun around on me hitting me incredibly hard in the wrist. I was speechless w. pain. It's a miracle it didn't break my wrist. This drill is so worth the extra money. for anyone new to concrete diamond hole saw drilling I might suggest starting your work with a 1/2" chuck to 5/8-11 or 1-1/4x7 tpi adapter with a normal variable speed drill and a simple garden hose spraying at the hole. This combo doesn't have nearly the same torque and it's a good way to see how you need to hold the drill precisely in line with the axis of the drill to prevent binding and the same near disastrous result I had.

well made for the price

I have used this machine without stand for few months and drilled with it over 76 holes 2” and 2.5” all through reinforced concrete (it takes about 20 minutes each if there is rebar), few others 4.5” The supplier guided me on how to perform the maintenance service adjusting the clutch (tightening to 11 ft/lbs with a torque wrench), so don’t worry if the machine starts skipping The water connection that comes with this drill is awful and has to be replaced, but I still give 5 stars This machine will pay for itself after couple of jobs; you will not regret buying it. Best value *****