rotary hammer for general drill

[Krokodil]

I'd like to upgrade my ryobi hammer drill to something with a bit more beef for steel drilling. I would also love to get a rotary hammer as I also do a lor of drlling into concrete. Will a rotary hammer with chuck adapter be ok for this purpose? I've heard there might be alignment issues from sds to tri chuch conversions.

 

[Packard V8]

Yes, a rotary hammer can be used for occasional drilling in steel.

No, as you surmise, the extra length of the chuck adapter makes it less strong and accurate than a standard drill motor.

Maybe, no, definitely, you need both. Used corded 1/2" drill motors are so dirt cheap these days, you can pick up a Milwaukee, older B&D, Skil, Thor, DeWalt or other quality tool for less than the cost of a chuck conversion for an SDS.

FWIW, after quite a bit of looking, I picked up an old Hilti TE-22 SDS hammer drill for cheap this week. This fills in that gap, as I already have an old 1/2" DeWalt and Craftsman, three 3/8" Craftsman, old Thor 1/4". None of these cost much of anything.

I sold a old beast of a B&D 1/2" drill for $15 last week. It was geared down so it would walk a sharp 1/2" drill through steel as quickly as most cheap 3/8" would drill through aluminum.

Bottom line, take your time. Good used power tools are so cheap these days, you can have several instead of trying to do everything with one.

jack vines

 

[Krokodil]

Thanks for the info!

 

[A_Pmech]

Depends on the hammer drill...

The larger hammer drills have overload clutches in them so they won't snap your wrist when the 6" core drill you're running seizes up in the hole.

Personally, if you need a heavy portable drill, it's best to purchase a magnetic drill press. A guy can do a lot of drilling with an old man and a 3/4" pipe handle, but the cost of a mistake is usually a broken arm or wrist. If you can't drill it with a 3/8" hand drill and a Unibit, get yourself a mag drill.

 

[pipsters]

The HF SDS drills have great reviews and there is a youtube video of someone using it, looks like it cuts thru rock like butter.

 

[Krokodil]

Looks like I have to get two drills then. Even if all the manufacturers advertise their rotary hammers with steel and wood capacity, it is not really made for that purpose.

Anybody use the makita Li-ion drills?

 

[Packard V8]

Personally, if you need a heavy portable drill, it's best to purchase a magnetic drill press. A guy can do a lot of drilling with an old man and a 3/4" pipe handle, but the cost of a mistake is usually a broken arm or wrist. If you can't drill it with a 3/8" hand drill and a Unibit, get yourself a mag drill.

Yes, a mag drill would be a great addition to any shop, but it is a limited use, very special purpose drill.
No, they are not an all-purpose drill. I can't count the hundreds of times I've had to put a 1/2" hole in steel in a place where a mag drill couldn't possibly have done it. Just in the corner of a truck frame channel last week, for one.
Maybe, a mag drill can be next on the quest list. However, I've never seen one for sale cheap.

Unibit - what's that? Never owned one and given the hundred pounds or so of twist drills already in the box, don't expect to be buying one any time soon.

jack vines

 

[A_Pmech]

Yes, a mag drill would be a great addition to any shop, but it is a limited use, very special purpose drill.
No, they are not an all-purpose drill. I can't count the hundreds of times I've had to put a 1/2" hole in steel in a place where a mag drill couldn't possibly have done it. Just in the corner of a truck frame channel last week, for one.
Maybe, a mag drill can be next on the quest list. However, I've never seen one for sale cheap.

Unibit - what's that? Never owned one and given the hundred pounds or so of twist drills already in the box, don't expect to be buying one any time soon.

jack vines

I don't think an all-purpose solution exists. But, having broken body parts when large drills hung up I have a tendency to be conservative in the "big hand drill" department.

What is a Unibit? It's a single-point drill patented in the 70's by Harry Oakes for drilling perfectly round holes in sheet metal. But, they also happen to be the answer to drilling a perfectly round 1" hole with a 3/8" hand drill and not breaking a sweat.

Irwin owns the trademark now and sells them under the Irwin name in hardware stores nationwide for an exorbitant price. I make mine for pennies and resharpen them with a die grinder.

 

[Packard V8]

But, having broken body parts when large drills hung up I have a tendency to be conservative in the "big hand drill" department.

When I was eighteen, I spent my one and only summer as a union-card-carrying helper in a steel bridge fabricating plant. Part of that job was on one end of a two-man power reamer. I saw one guy flung off a 20-foot-high bridge section when he wasn't braced before he pulled the trigger.

What is a Unibit? It's a single-point drill patented in the 70's by Harry Oakes for drilling perfectly round holes in sheet metal.

Does the unibit work on thicker-than-sheet-metal?

I make mine for pennies and resharpen them with a die grinder.

Care to share your techniques?

jack vines

 

[Krokodil]

Every one here is saying that a cordless cannot take the place of a corded drill, yet the drilling capacity in steel is the same for most 18v and ±650w drills. How can I convert between battery power and ac?

 

[Packard V8]

Today's battery powered drills are every bit as strong as the AC drills - UNTIL THE BATTERY DIES.

I just passed on an older Hilti battery rotary hammer for $50 because it only had one battery, which was a little weak and a new from-Hilti-only battery is $250!

jack vines

 

[Krokodil]

If there is no real difference in the power between a corded drill and a battery one, I might as well get a mobile one.

Currently thinking of a Makita 18V Li-ion drill driver (no hammer) and a small rotary hammer. Maybe a Bosch or also a Makita that can be cordless as they use the same battery.

 

[A_Pmech]

Jack,

I can imagine that was pretty common in a place like that. Most of the bridge reaming I've seen was done with air impacts but I think that's a fairly recent development.

The thickness limit on standard Unibits is about 1/8" to 1/4" depending on the bit. You can drill deeper than that, but the hole becomes stepped just like the bit. To drill thicker materials all you need is to make a Unibit with a deeper step distance, say 10% greater than the thickness of the material so no more than one step is engaged at a time.

A little Unibit story:

One afternoon I needed to rent a large trailer in an emergency. Unfortunately, it took something like a 2" ball, which I didn't have. All the stores in town had the correct ball, but not in a 3/4" shank to fit the bumper on my truck. All they had were 1" and 1.25" shanks in that ball size.

Rather than drive home, drill it out and drive all the way back up town (killing an hour), I bought a 1" Unibit at the hardware store and went back to the rental place. At the rental place, I borrowed one of their drills and proceeded to enlarge the hole in the bumper to 1" in about 30 seconds, much to the amazement of the store owner and staff.

Next time I make one I'll try to take some photos. They're very easy to make, the only critical dimensions are the cutting angle and the end relief. Have a look at one in a hardware store and you'll see what I mean. The ones I make require a pilot hole for simplicity.

When I was eighteen, I spent my one and only summer as a union-card-carrying helper in a steel bridge fabricating plant. Part of that job was on one end of a two-man power reamer. I saw one guy flung off a 20-foot-high bridge section when he wasn't braced before he pulled the trigger.

Does the unibit work on thicker-than-sheet-metal?



Care to share your techniques?

jack vines

 

[foolishpride]

Here's a picture of a Unibit: