Rotary Hammer Recommendation

[LopezBart]

How long do bits last and are name brand that much better?

I bought 2 12" long Bosch 9/16" SDS drill bits for drilling 40-odd holes for my shop's frame anchors. One got it done w/o any perceived slow down or dulling. Compared to the old hammer drill days 30 years ago, the performance of an SDS drill and good bits is pretty amazing.

 

[KnurledNut]

Next stupid question.
How long do bits last and are name brand that much better?

I need 12 holes for mounting my lift (Guessing 3/4")

Its almost impossible to give an exact number as there are lots of variables that affect longevity.
I would expect a quality 3/4 bit to drill 50-100 holes before closely inspecting. Of course, it could have an early failure or last much longer than those numbers. I've had them do both.
The sides of the carbide insert wear leading to reduced hole diameter, which can be an issue for certain types of anchors.
I've used many quality brands and they have all performed well. The only bits I would consider to be exceptionally better is HILTI.

 

[N_Jay]

Thanks all.
Sounds like a "brand name" is worth it, and I need one, but should have spare on hand.

 

[N_Jay]

I have used a hammer drill, but mostly for very small holes and breaking up concrete, but never a Rotary Hammer for wedge anchors.
Other than being carful to drill as cleanly as possible and blowing ay debris from the hole, any other tips to get a good solid anchor?

 

[MichaelP]

Frankly, you will hardly need to pay much attention to the debris (although it's always a good idea). As for drilling, Bosch has a depth gauge, so all you need is to choose a recommended for your anchor drill diameter and drill to the gauge stop. Nothing special.

 

[N_Jay]

Sounds good.
The engineer in me looks at those anchors and wonders . . .

 

[mike93lx]

Sounds good.
The engineer in me looks at those anchors and wonders . . .

Wonders what?

 

[Hakeem]

I have used a hammer drill, but mostly for very small holes and breaking up concrete, but never a Rotary Hammer for wedge anchors.
Other than being carful to drill as cleanly as possible and blowing ay debris from the hole, any other tips to get a good solid anchor?

Stick a zip tie or three into the hole to give the anchor more to bite into.

If you can’t get the wedge anchor to bite enough to spin the nut down, use an angle grinder + zip disc to cut a slot into the top of the wedge. now you can use a flat head screwdriver to hold the anchor steady while you torque the nut down.

 

[N_Jay]

Wonders what?

I am sure they hold, but they just look like there is not much holding it in.
Yes, I get they put the concrete into compression several inches below the surface.

Stick a zip tie or three into the hole to give the anchor more to bite into.

If you can’t get the wedge anchor to bite enough to spin the nut down, use an angle grinder + zip disc to cut a slot into the top of the wedge. now you can use a flat head screwdriver to hold the anchor steady while you torque the nut down.

ZIP-TIES????
Uhhhh, that sounds like a really bad idea (to fix an over diameter hole)
We are going to apply tones of force between the expansion piece and the concrete and you think adding a layer of (relatively) easily compressed plastic improves the situation?

Not sure why the anchor would turn if the hole is not oversized. Is that a big problem (only reference I saw about the anchor turning was concerning over tightening.
do you use a torque wrench?

 

[MichaelP]

Hakeem meant to use something to prevent anchor rotation until it expands and bites into concrete. You may need it if the hole is oversized a bit. I, personally, never needed it with concrete anchors I used, but this problem is not unheard of.

 

[N_Jay]

I think Hakeem meant to use something to prevent anchor rotation until it expands.

OK, but shouldn't it be snug to start?

 

[MichaelP]

It should, but in reality, you can often push the anchor in using you finger, and it's sufficient to provide temporary retention until anchor expands by fastener.

 

[dnschmidt]

For bits I like Diablo with the four chisel points.

 

[MichaelP]

NJay,

Don't forget that the anchor is not freely suspended in the hole: the hole has a bottom, and when you apply pressure vertically, the friction against the bottom helps preventing initial rotation of the anchor.

 

[N_Jay]

It should, but in reality, you can often push the anchor in using you finger, and it's sufficient to provide temporary retention until anchor expands by fastener.

All the instructions say to drive it in with a hammer, so wondering how easy it is to accidently over "ream" the hole when drilling?

NJay,

Don't forget that the anchor is not freely suspended in the hole: the hole has a bottom, and when you apply pressure vertically, the friction against the bottom helps preventing initial rotation of the anchor.

The instructions I have read say the hole should be 1/2 inch beyond the length of the anchor.

 

[MichaelP]

N_Jay, I think you need to temporarily turn off the engineer in you, drill a hole, put an anchor in and see how it works.
Then turn on the engineer and explain why it worked just fine.

P.S. I have to admit that I'm exactly like you in this respect. I have to understand how and why something works before attempting to do anything.

 

[N_Jay]

N_Jay, I think you need to temporarily turn off the engineer in you, drill a hole, put an anchor in and see how it works.
Then turn on the engineer and explain why it worked just fine.

P.S. I have to admit that I'm exactly like you in this respect. I have to understand how and why something works before attempting to do anything.

"See how it works" is irrelevant when failure is catastrophic.

But, yes, I am overthinking the 5 to 10 bolts protecting me from death.

 

[MichaelP]

Time to think about somebody bonded and insured who earns living doing it. At least, you'll rest assured your widow gets some money after your early departure.

By the way, when they speak about extra hole depth they take drill tip/anchor tip geometry into consideration. The anchor should rest against the bottom when fully inserted.

 

[Hakeem]

I am sure they hold, but they just look like there is not much holding it in.
Yes, I get they put the concrete into compression several inches below the surface.


ZIP-TIES????
Uhhhh, that sounds like a really bad idea (to fix an over diameter hole)
We are going to apply tones of force between the expansion piece and the concrete and you think adding a layer of (relatively) easily compressed plastic improves the situation?

Not sure why the anchor would turn if the hole is not oversized. Is that a big problem (only reference I saw about the anchor turning was concerning over tightening.
do you use a torque wrench?

Yes, the easily compressible plastic improves the interface between the metal anchor and the concrete. Gives the smooth shank of the anchor something to bite into before the wedge expands. It won’t impact strength, just prevents the “oh **** I can’t tighten my anchor because it won’t stop spinning and I can’t pull it out either” moments.

Use epoxy if you prefer, or even nothing. Just sharing a “tradesman secret” that I learned from an old timer.

 

[N_Jay]

Time to think about somebody bonded and insured who earns living doing it. At least, you'll rest assured your widow gets some money after your early departure.

By the way, when they speak about extra hole depth they take drill tip/anchor tip geometry into consideration. The anchor should rest against the bottom when fully inserted.

How to Install Wedge Anchors | Concrete Anchor Instructions | Fastco Inc.

www.fastcoinc.com

Read step 3

And another:

How to Install Concrete Wedge Anchors

A quick overview of the types of concrete wedge anchors, the correct depth to drill, and steps for installation.

www.forconstructionpros.com

 

[N_Jay]

Yes, the easily compressible plastic improves the interface between the metal anchor and the concrete. Gives the smooth shank of the anchor something to bite into before the wedge expands. It won’t impact strength, just prevents the “oh **** I can’t tighten my anchor because it won’t stop spinning and I can’t pull it out either” moments.

Use epoxy if you prefer, or even nothing. Just sharing a “tradesman secret” that I learned from an old timer.

Seems that someone on some site that makes or sells anchors would have mentioned that. (or made a fastener with a nylon covering.)

I'm no expert, but do know lots of "old-timers" with lots of bad advice

 

[MichaelP]

Hakeem,
I tend to use ConFast Concrete Drop-In Anchors for almost all my machinery/devices anchoring needs. My suggestions above are based on use of this type of anchors, and it should've been definitely mentioned. Other anchor types may require slightly different technique. My fault.

 

[mike93lx]

Time to think about somebody bonded and insured who earns living doing it. At least, you'll rest assured your widow gets some money after your early departure.

By the way, when they speak about extra hole depth they take drill tip/anchor tip geometry into consideration. The anchor should rest against the bottom when fully inserted.

"bonded and insured" is a phrase used too often.

No one is getting a bond for something like this and bonds are something very rare in residential anyway. Insurance is valid but a settlement doesn't bring you back to life.


/rant off

 

[MichaelP]

But it brings new opportunities to the widow.

 

[mike93lx]

But it brings new opportunities to the widow.

Hopefully she can enjoy a new boat with her boyfriend

 

[N_Jay]

Hakeem,
I tend to use ConFast Concrete Drop-In Anchors for almost all my machinery/devices anchoring needs. My suggestions above are based on use of this type of anchors, and I should've definitely mentioned. Other anchor types may require slightly different technique. My fault.

Thanks.

These forum make it too easy to get confused.

 

[N_Jay]

. . . . a settlement doesn't bring you back to life.


/rant off

When I bought me under-lift stands, the manager at HF asked if I wanted to buy the extended warranty.
I said; "If they fail my wife won't know where to return them".
She gave me a odd look. Not sure she understood.

 

[bcradio]

Thanks.

These forum make it too easy to get confused.

You just need to follow the advice above and drill a practice hole out of the way and insert the fastener to see how it works. Once you see first-hand, you will know and have the confidence to do the rest. Stop overthinking these... 99.99999% of the tradespeople who install these haven't put 1/100th of the amount of mental effort you have into this and all of their fasteners are holding up great. Get-r-done son!

 

[N_Jay]

You just need to follow the advice above and drill a practice hole out of the way and insert the fastener to see how it works. Once you see first-hand, you will know and have the confidence to do the rest. Stop overthinking these... 99.99999% of the tradespeople who install these haven't put 1/100th of the amount of mental effort you have into this and all of their fasteners are holding up great. Get-r-done son!

Unfortunately they don't provide spare "Practice" fasteners.
I have some smaller ones left over form building the shop (the ones used around the sill, but unless we have a tornado those are not going to experience any stress at all.
I will probably used them to anchor some small equipment once I am sure I know where I want it.

 

[sparky 1971]

Wow. If it were me I would drill the holes, install the anchors and get it over with. If, for some reason, an anchor would slip upon attempting to tighten it I would do what I always do and use a stripped piece of 14 gauge stranded wire to make a shim. The wire will get smashed and nobody will ever know the difference. I would also know that it's a lift, it's heavy, and it's bolted to the floor, so it's not going to fall up even if one of the anchors did start to slip on installation and I had to improvise a way to get it tight. Use a new bit, drill it straight and there should be no problem.

 

[N_Jay]

Well, it is a two-post lift so there is always leverage force on the columns.

If one doesn't tighten, I can go up one size or epoxy in a threaded bar.

 

[Hakeem]

Seems that someone on some site that makes or sells anchors would have mentioned that. (or made a fastener with a nylon covering.)

I'm no expert, but do know lots of "old-timers" with lots of bad advice

Absolutely. On a similar note, I know plenty of “theorists” with zero practical experience who know better than the guys who go out and do it everyday. Good luck with your lift.

Wow. If it were me I would drill the holes, install the anchors and get it over with. If, for some reason, an anchor would slip upon attempting to tighten it I would do what I always do and use a stripped piece of 14 gauge stranded wire to make a shim. The wire will get smashed and nobody will ever know the difference. I would also know that it's a lift, it's heavy, and it's bolted to the floor, so it's not going to fall up even if one of the anchors did start to slip on installation and I had to improvise a way to get it tight. Use a new bit, drill it straight and there should be no problem.

Bingo. This guy has clearly sunk a few concrete anchors in his day. A piece of stranded wire goes into every tapcon hole I drill for conduit strapping, unistrut, etc. Metal or plastic are code compliant

 

[Hakeem]

Hakeem,
I tend to use ConFast Concrete Drop-In Anchors for almost all my machinery/devices anchoring needs. My suggestions above are based on use of this type of anchors, and it should've been definitely mentioned. Other anchor types may require slightly different technique. My fault.

Ahh, never used those. Around here it’s all wedge anchor for bigger stuff. I really should try the sleeve anchors for kicks, if nothing else. I know traditionally lead sleeves were used. It’s all operating on the same principle as the zip tie or wire - some type of soft, malleable substrate that conforms to the concrete hole to provide a better interface for the anchor.

 

[mike93lx]

Absolutely. On a similar note, I know plenty of “theorists” with zero practical experience who know better than the guys who go out and do it everyday. Good luck with your lift.



Bingo. This guy has clearly sunk a few concrete anchors in his day. A piece of stranded wire goes into every tapcon hole I drill for conduit strapping, unistrut, etc. Metal or plastic are code compliant

Shenanigans. If the hole isn't perfect, you cut out the section and repour

 

[N_Jay]

Absolutely. On a similar note, I know plenty of “theorists” with zero practical experience who know better than the guys who go out and do it everyday. Good luck with your lift.

It's the balancing act.

Theoretical Experts don't always know how, but usually know why.
Practical Experts often know how, but sometimes don't know why.

I like asking both to get a full picture.

Also, my stress level just went down because a guy who has done a few lifts is coming by to help.

 

[MichaelP]

Good decision! Just try to talk to the guys he installed the lifts for. Just to make sure all of them still answer the phone.

 

[N_Jay]

Good decision! Just try to talk to the guys he installed the lifts for. Just to make sure all of them still answer the phone.

Well he did his own and is still around.

 

[MichaelP]

Who knows. He may not like having competitors.

 

[pizza]

i was trying to decide between bosch GBH2-28L (bulldog xtreme max) and RH328VC sds-plus roto hammers...

Product comparison | Bosch Professional

www.boschtools.com

anyone know which is the newer product?

very similar price, weight, and other specs. aside from the obvious form factor difference (straight vs 90° build)...

GBH2-28L has slight edge in: amps, bpm, rpm, weight
RH328VC has slight edge in: max core bit diameter, and maybe build quality (claims to have metal+plastic housing vs just plastic on the bulldog)?

they have clearly different anti-vibration mechanisms. the RH328VC has a shock absorber looking thing on it, and the bulldog has some internal mechanism you can't see.

different anti-kickback tech also. the bulldog's is electric ("uses an integrated sensor to stop tool rotation during bit bind-up situations"), and the RH328VC has a clutch ("clutch disengages torque transmission if the bit gets into a bind situation").

unlike the RH328VC, the bulldog can reverse direction.

anyway, i ended up going with bulldog xtreme max because i could get into it for cheaper, and it's not a tool i use that often.
i got it for like $120 shipped as a refurb from cpo (bought direct). used the new customer $20 coupon thing if you sign up for their spam. plus apparently 5% rakuten cash back.

 

[mike93lx]

Their manuals both have 2017 revision dates in them, so neither are recent releases.

I have a 11255vsr bulldog extreme and its been great. Drilled a dozen 3/4" holes in a slab for one project and handled it fine. It doesn't hit super hard, but it removes tile faster than doing it with a hammer and chisel. I now also have a larger Sds max rotary hammer and a 35lb jackhammer, so the bosch won't be doing much demo, but it's my go to for drilling a hole as Sds plus bit are a lot cheaper than sdsmax