Help - Core drill choices

[wb4rt]

MetalMan23 has convinced me that I need to core drill my handrail posts instead of using base plates. He referred me to Amazon as a source for inexpensive core drill motors.

I cannot justify $1000+ for a name brand as I will only use it for handrails 4-5 times a year.

Has anyone used one they particularly like or dislike? And why? Where did you purchase it?

Any tips or advice since I have never used one or installed handrails that way?

Hopefully this thread can serve as a reference for others interested in handrails.

Thank you in advance for sound, thoughtful advice.

[ronsii]

I have bought several core drills all import... if I did more of these jobs that need corring I'd probably get a better(name brand) core rig.

The first one I bought oh I don't know 10-12 years ago....I think it was about 100-120 bux delivered and then I bought an assortment of bits I thought would work 1-1/2, 1-15/8, 1-3/4... all too small for 1.5 railing unless you're the greatest fabber out there I found that a minimum of 2.5inch preferably 3 inch will suffice for measuring errors and minor adjustment.. however it'll take more 'setting compound' but it's worth it not to have other issues
I think the bits ran about 30-50 bux for anything up to 3-4 inch OD and 16+ inches long and unless you're constantly going through big rebar you'll probably get 100 holes out of a standard bit(import).

On one of my first jobs the power switch fried itself fortunately I only had a few holes to go and after half an hour of core rig surgery I had it fixed(hardwired the switch on) so I had to unplug it to stop it!!! was interesting when it would jam!!! that night I ordered a backup of course if wouldn't be til the next job a few weeks later that I would find out about the different core rig threads and how my backup drill had metric threads for the bits instead of the standard 1-1/4 that night I ordered another backup.... but soon found out that even when they say the drill is using standard threads it isn't (they lied!!!)

So the other day I had to do some bigger holes and ordered up a couple more big rigs these will handle up to 10 inch and I got a few bits to go with them... the bits 100-200 ea. depending on quality the drills were ~200-230 ea. they seem to work good.. little different setup - these come with an inline gfci breaker and an actual circuit breaker euro style for the on/off switch.. but they aren't mag switches.. so watch out if you trip something one other thing... these are metric!!! except for the bit arbor it is the 1-1/4 standard but the rest is metric!!!.... a problem which I plan to rectify on mine when I get time... I will drill all the threads out and helicoil them out to standard stuff.... makes things a lot simpler when you need to 'improvise' to get a job done

Lastly, I NEVER buy from AMZ(they're evil) most of my stuff is from ebay sellers or direct importers on the west coast.. usually cali.

[ronsii]

Here is one of the last drills I bought... it's a bigger one so has mounting plate.. for handrails I just did them freehand with the cheaper hand drill rigs.
I think these guys sell the smaller ones also...
https://www.ebay.com/itm/4450W-Diamo...72.m2749.l2649

[ronsii]

Oh.... one other thing(again) as long as I'm here I probably put this in other threads long ago but for placement of the holes I would just put my boots in a 'V' shape to get the bit started where I wanted it and then push down for a minute or three depending on how big you're boring and how deep... I had also made up some plywood guides with a 'V' cut out of the ends that you could stand on if there was enough room, this would hold the bit completely immovable so it could not wander if the holes had to be very precise!!! most aren't so I doubt you'll have an issue there

Oh, you're gonna get a little wet

One more thing I just remembered is so far all these import drills do NOT use stainless in their wet parts... so if you don't run oil...something through them after use they will rust and take out the seal for the water swivel... and then you WILL get a lot wetter the next job you do... again I learned this the hard way


Oh... and when I'm hand drilling I usually rest the handle on my leg so if it stalls I can control it! the smaller hand drills aren't like a good old black and decker hole hawg where it can break your leg but they aren't wussies either they can get away from you if you're just using hands to control them... for straight drilling in 4-6 inch sidewalk you shouldn't have issues... it's when you start drilling in stub walls with rebar layers and plates that can get grabby! I also like to drill all the way through sidewalks as it gives a place for the water to drain and not break the walk when freezing and the railing fills up with water on stub walls you can't do this so you have to have other plans about keeping the water out of the core hole!!! at least around here and other places it freezes good. of course most everyone that does this doesn't have any means to keep water out....and it shows after a few seasons... the walls start blowing apart from the inside

[walker]

I bought a big Milwaukee years ago, and it has more than paid for itself. Before I bought one, and even now if I am busy, or the flooring is super expensive, I just hire it out. It usually comes to about $25 per hole.

[forhire]

Have you tried the SDS style drills? Generally you can run them free hand. I don't do hand rails so maybe someone who uses these will chime in.

The smallest core drill I have is 5". The issue with a core drill is the need to anchor it. I generally sink anchors but my Milwaukee also has a vacuum foot that I use when I do not want to leave anchor holes. I picked up my drill used and it paid has easily paid for itself.

[wb4rt]

Have you tried the SDS style drills? Generally you can run them free hand. I don't do hand rails so maybe someone who uses these will chime in.

The smallest core drill I have is 5". The issue with a core drill is the need to anchor it. I generally sink anchors but my Milwaukee also has a vacuum foot that I use when I do not want to leave anchor holes. I picked up my drill used and it paid has easily paid for itself.

That is a good point about the SDS. I have a nice Bosch SDS plus and I see adapters that will work. I considered that but don’t know about keeping the core wet and it doesn’t have a clutch in case it gets hung up.

Has anybody drilled cores with SDS? Any issues or tips on how well it works? Might be easier than I think. And cheaper.

[ronsii]

That is a good point about the SDS. I have a nice Bosch SDS plus and I see adapters that will work. I considered that but don’t know about keeping the core wet and it doesn’t have a clutch in case it gets hung up.

Has anybody drilled cores with SDS? Any issues or tips on how well it works? Might be easier than I think. And cheaper.

I haven't tried any of the sds core bits... but do use regular sds up to 1-1/8th a lot!!! the only hangup I could see would be if you get into rebar although regular bits will chew their way(sometimes) through a little rebar when you hit anything over 1/4-3/8th inch bar square on your done with the hole!!! or you sit there til the tips break off BTDT

[ronsii]

I have 5-6 bosch sds drills and all of them have clutches if you stick the bit....I am curious which model you have that doesn't have one? or maybe it just takes a *lot* of force to open the clutch up!!! I know I can break 1/4 inch bits all day long if I'm not careful!!! and have broke 3/8 bits but usually they will trip the clutch

[wb4rt]

I have 5-6 bosch sds drills and all of them have clutches if you stick the bit....I am curious which model you have that doesn't have one? or maybe it just takes a *lot* of force to open the clutch up!!! I know I can break 1/4 inch bits all day long if I'm not careful!!! and have broke 3/8 bits but usually they will trip the clutch

I’m not certain there is no clutch, but never had it trip if there is one. I was concerned of the torque if it hangs up.

Thanks for the reply!

[Stick-man]

I’m not certain there is no clutch, but never had it trip if there is one. I was concerned of the torque if it hangs up.

Thanks for the reply!

I use a Hilti SDS for coring 3" quite often. It's very manageable when it locks up. The one I use won't break a leg, maybe just a bruise or something. Also, the bits we use have a center bit to keep it straight. But, they're only maybe 3" deep so if you will core thru you will have to find a longer bit.

[tapwelder]

How long does it take to drill a hole with a percussion core bit? Into solid concrete. I wouldn't suggest using one on brick steps. It could move them or crack them. Especially near the edge.

I have an adaptor to use a core saw on for a regular large drill. Issue I had... the adapter adds about 2 inches in length. And creates a weak point with the small shaft, it readily bent. Wobbly saw = no good.

9" Angle grinders work well , plenty of leverage for safety. Speed might be a bit high for smaller bits. But it will work and fast. Just not economical on saw consumption, comparable to lower rpm tools. I get about 70 holes with my WEKA drill, failure due to straight teeth wear.
With my angle grinder 30, mostly due to broken teeth or saw core being abraded away.

It is not easy on the grinder either. Not sure why...perhaps there is a lot more torque than it feels. Though I never started with a new grinder I just bought second hand grinders.

A large core rig is not for general rail install. Heavy loading and unloading, lots of shimming, limited access against walls. And lots of position and adjusting.

[wb4rt]

I’m fine buying one of the Chinese handheld core drills (about $250). I think I will go that route.

Here is my next dilemma- the jobsite is brick pavers on a concrete block foundation. There is not a layer of concrete between the block and pavers. I am thinking they used the block as concrete form and maybe filled in the blocks. Any issues core drilling and installing in this?

I appreciate everyone’s comments as I want to do a good job installing. I have always used baseplates but I am convinced drilling is a better installation.

[ronsii]

I’m fine buying one of the Chinese handheld core drills (about $250). I think I will go that route.

Here is my next dilemma- the jobsite is brick pavers on a concrete block foundation. There is not a layer of concrete between the block and pavers. I am thinking they used the block as concrete form and maybe filled in the blocks. Any issues core drilling and installing in this?

I appreciate everyone’s comments as I want to do a good job installing. I have always used baseplates but I am convinced drilling is a better installation.

Not quite sure what you mean by not a layer of concrete between them...???

We have ran into walkways where they poured a rat slab on the dirt(rough uneven unlevel in... everything) then they poured between 3/4inch and 4 inch of some kind of cementious semisoft??? Then a layer of grout the pavers were set into. Not a big deal but very disturbing when trying to core it.

[wb4rt]

Not quite sure what you mean by not a layer of concrete between them...???

We have ran into walkways where they poured a rat slab on the dirt(rough uneven unlevel in... everything) then they poured between 3/4inch and 4 inch of some kind of cementious semisoft??? Then a layer of grout the pavers were set into. Not a big deal but very disturbing when trying to core it.

Hey Ronsil,

I mean there is not a 2”-3” layer of concrete on top of the blocks, then mortar bed for pavers. It’s possible they used sawn blocks as form with concrete flush with top of blocks. Of course it could be the holes of blocks are filled and concrete swung level with blocks across the porch.

My concern is if I drill through pavers, thin mortar bed, and into blocks if that will be strong for handrails? Kind of like you said about the “rat slab”. If only mortar in block holes that may not be as solid as needed. I may be overly cautious but just don’t want to cause any problem.

[ronsii]

Hey Ronsil,

I mean there is not a 2”-3” layer of concrete on top of the blocks, then mortar bed for pavers. It’s possible they used sawn blocks as form with concrete flush with top of blocks. Of course it could be the holes of blocks are filled and concrete swung level with blocks across the porch.

My concern is if I drill through pavers, thin mortar bed, and into blocks if that will be strong for handrails? Kind of like you said about the “rat slab”. If only mortar in block holes that may not be as solid as needed. I may be overly cautious but just don’t want to cause any problem.

I think mortar inside of block holes would be fine...I'm guessing you mean CMU's when you say blocks... most of the railings we cored were done at about 5 foot spacing and down into at least 4 inches of cement.. if you can't achieve that kind of depth I would try to drill deeper and use more setting compound just to get strength against leverage... And if you mean there may be hollow under there then same thing I would get into it and fill it with mortar or something similar.

[Brett]

We core drill every day .
Usually 2 1/2 " , some 50mm and some 75mm
You cannot go past a Weka DK1603
Highly recommend if available in US

[William McCormick]

I always used the handheld Eibenstock, I think you can get it for about $800.00 I like the longer one with two speeds. I use it at high speed with a two-inch bit, to core for 1 1/4" I.D. pipe with a 1 5/8" O.D. You can mark and core six to eight 2" diameter holes 4' deep in about 15 minutes. I usually get 30 to 40 holes out of a 2" diamond bit, the last ten bind more while coring. I use QuickRock to fill the holes. https://www.jansensupply.com/product...spx?dataid=QRK

Do not under any circumstances listen to the directions on the QuickRock. When you mix it you want a thick chocolate milk consistency, I put a little water into the small container I want to mix it in, and then the QuickRock and then slowly add more water it does not need much water. I mix enough to pour one or two holes at a time. It sets so fast especially in the summer that is all you can get done. I mix it in a large coffee cup and do one and a half holes at a time, or if I have plastic paint cups I do two holes at a time. Get the soft paint cups so you can bend them into a point to pour from. You put your container up against the railing and let it run down the rail into the hole.

What I do is lay my rail in place and level it, sometimes I use the double handled wooden clamps to hold it up and hold it level if I am alone. and then, with a nice new four-inch soapstone up against the vertical, I create a mark on the stoop and steps below the rail, some verticles might be off the stoop the reason for the 4-inch soapstone. You do not need to trace around the pipe just mark four sides 90 degrees apart. When you first core you should bring a piece of plywood with a two-inch hole in it that you can line up and stand on while you start the core. After a while, and from forgetting to bring the plywood you get very good at figuring out how to start it between the tips of your boots. Once the hole is started you do not need the plywood or your boots.

I have heard there are some decent core drills out there, I just haven't found them yet. But it has been a while since I looked for one. The core rigs are somewhat useless for rails on a stoop and most move too slowly for a two-inch bit. The QuickRock recommends a four to a six-inch core for a 1 1/4" pipe, that is just insane and looks like such crap that you cannot even imagine. I actually get cement dye and add some to the quick rock so it looks like the rail grew out of the stone. But I cheat I pour the pure QuickRock to 3/4" or 5/8" below the surface on all the holes, and then at the end, I go back with the dyed QuickRock and finish it off. I also pour the dyed cement high, wait till it sets a little, and shape it, like a weld around the vertical. All this sounds mind-boggling however I am usually finished totally within an hour from when I arrive for a simple set of steps. The directions on the QuickRock say it is good to use below freezing this is not the case. Never try it in the cold unless you have a kerosene space heater with you to preheat the stoop and steps. In the sun on a hot day use ice water to mix it and only do one hole at a time and pour anything left in the next hole.

You do not want to pour the quick rock on the stoop as it will find the pores of the brick, stone, or cement and stay there. I carry a little stainless steel wire brush to clean off any unwanted stuff. Your best bet is to pour it, do any dying if you like that, and then quickly clean up any material before it hardens fully. QuickRock is grey like cement. You can use a hose with low pressure to help wash away the contamination you remove because the material around the verticles usually gets hard fast, except on cold days.

Start coring on the bottom step, so you are not standing in water the whole time you core.

Sincerely,

William McCormick

[William McCormick]

I always used the handheld Eibenstock, I think you can get it for about $800.00 I like the longer one with two speeds. I use it at high speed with a two-inch bit, to core for 1 1/4" I.D. pipe with a 1 5/8" O.D. You can mark and core six to eight 2" diameter holes 4' deep in about 15 minutes. I usually get 30 to 40 holes out of a 2" diamond bit, the last ten bind more while coring. I use QuickRock to fill the holes. https://www.jansensupply.com/product...spx?dataid=QRK

Do not under any circumstances listen to the directions on the QuickRock. When you mix it you want a thick chocolate milk consistency, I put a little water into the small container I want to mix it in, and then the QuickRock and then slowly add more water it does not need much water. I mix enough to pour one or two holes at a time. It sets so fast especially in the summer that is all you can get done. I mix it in a large coffee cup and do one and a half holes at a time, or if I have plastic paint cups I do two holes at a time. Get the soft paint cups so you can bend them into a point to pour from. You put your container up against the railing and let it run down the rail into the hole.

What I do is lay my rail in place and level it, sometimes I use the double handled wooden clamps to hold it up and hold it level if I am alone. and then, with a nice new four-inch soapstone up against the vertical, I create a mark on the stoop and steps below the rail, some verticles might be off the stoop the reason for the 4-inch soapstone. You do not need to trace around the pipe just mark four sides 90 degrees apart. When you first core you should bring a piece of plywood with a two-inch hole in it that you can line up and stand on while you start the core. After a while, and from forgetting to bring the plywood you get very good at figuring out how to start it between the tips of your boots. Once the hole is started you do not need the plywood or your boots.

I have heard there are some decent core drills out there, I just haven't found them yet. But it has been a while since I looked for one. The core rigs are somewhat useless for rails on a stoop and most move too slowly for a two-inch bit. The QuickRock recommends a four to a six-inch core for a 1 1/4" pipe, that is just insane and looks like such crap that you cannot even imagine. I actually get cement dye and add some to the quick rock so it looks like the rail grew out of the stone. But I cheat I pour the pure QuickRock to 3/4" or 5/8" below the surface on all the holes, and then at the end, I go back with the dyed QuickRock and finish it off. I also pour the dyed cement high, wait till it sets a little, and shape it, like a weld around the vertical. All this sounds mind-boggling however I am usually finished totally within an hour from when I arrive for a simple set of steps. The directions on the QuickRock say it is good to use below freezing this is not the case. Never try it in the cold unless you have a kerosene space heater with you to preheat the stoop and steps. In the sun on a hot day use ice water to mix it and only do one hole at a time and pour anything left in the next hole.

You do not want to pour the quick rock on the stoop as it will find the pores of the brick, stone, or cement and stay there. I carry a little stainless steel wire brush to clean off any unwanted stuff. Your best bet is to pour it, do any dying if you like that, and then quickly clean up any material before it hardens fully. QuickRock is grey like cement. You can use a hose with low pressure to help wash away the contamination you remove because the material around the verticles usually gets hard fast, except on cold days.

Start coring on the bottom step, so you are not standing in water the whole time you core.

Sincerely,

William McCormick

To start the hole you start with no water. I start all the holes dry I go about 1/4" to 3/8" deep, then hit the water and start coring the bottom holes of both left and right rails first. If you turn on the water you can wash away your soapstone or other markings. The bit does not get hurt because it does not heat up going in 3/8" deep.

Sincerely,

William McCormick

[William McCormick]

https://www.contractorsdirect.com/Ei...Wet-Core-Drill

A Turkey baster works great for removing water in the core hole. You cannot leave water in the core it will mess up the Quickrock. Most cores in brick are not waterproof, so the water slowly drains away, but some do not drain and have to be dried out. You can use a rag to suck it up, and then ring it out too. If you are on a stoop that the cores are leaking you can mix up a thick batch of quick rock and just pour a little into all the holes that are leaking not filling them but just to seal the hole. Then finish them with the chocolate milk consistency QuickRock. It takes some practice before you can tell if you have a leaker or if you have sealed it or not. The trick is not to panic, better to waste a cup of QuickRock than to spill it all over or set the rail incorrectly.

Bring lots of paper cups and or soft paint cups.

The reason I like the long Eibenstock is that you can more easily see your core angle as you are coring.

Sincerely,

William McCormick

[Munkul]

For handrailing? A few times a year? I'd rather just weld base plates on, use a normal SDS drill and anchor bolts. I certainly wouldn't want a specific core drilling machine... maybe a combined SDS drill with a clutch or anti-kickback for a core drill bit.

[William McCormick]

Also with the long Eibenstock, you can let the side handle rest up against your leg to keep it from spinning. And stand upright not bending over for the whole duration of the core. It is so much easier to see the core angle when you are not bending over. This alone is well worth any price.

Sincerely,

William McCormick

[tapwelder]

For handrailing? A few times a year? I'd rather just weld base plates on, use a normal SDS drill and anchor bolts. I certainly wouldn't want a specific core drilling machine... maybe a combined SDS drill with a clutch or anti-kickback for a core drill bit.

My thought, too.

[ronsii]

Also with the long Eibenstock, you can let the side handle rest up against your leg to keep it from spinning. And stand upright not bending over for the whole duration of the core. It is so much easier to see the core angle when you are not bending over. This alone is well worth any price.

Sincerely,

William McCormick

Yep, this is exactly how I do my cores with the handheld


Also I usually have my shopvac running to take care of water/slurry running places it shouldn't... and for sucking out the holes

[wb4rt]

For handrailing? A few times a year? I'd rather just weld base plates on, use a normal SDS drill and anchor bolts. I certainly wouldn't want a specific core drilling machine... maybe a combined SDS drill with a clutch or anti-kickback for a core drill bit.

This is what I have done for the last 4 years but I always believed drilling was a better technique than baseplates. I continue to get these handrail jobs so at some point you have to make the investment, learn new skills, and improve your business. I’m not planning to spend $1000, but for around $400 it’s doable. My latest job is more detailed than a simple rail and I’ll make more than enough to justify the investment.

Thanks to everyone for very good and needed advice. Please continue posting your recommendations and experience as it will help me and others who may be interested. I do not recall any other threads on this topic.