Hurricane Drill Intrest?

I don't know how I would swap out the bit without major herky jerky

Why not embrace something that is simple rather than drooling over something that is unnecessarily complex.

Sounds like some folks are happy with the Roc Pec. Maybe Minerals and a Roc Pec advocate could have a drill-off. My money would be on Minerals, regardless of the drill holder!

Greg, I used to grind down the SDS 3/8" bits so the carbide tips were sharp like a chisel bit. We used a diamond wheel on a regular grinder to do them.

One idea we never fully tested was to create some sort of knurled nut at the end that one could simple hand tighten.

But as a fan of the rocpec and its simplicity, why doesnt someone get into making HSS style bits that have the SDS style connection?

I don't reckon the keyless chuck would work: heavy, and not really designed to be impacted.

As far as the drill chuck design, I have tried this as well, they work ok but are heavy and big....

Bosch makes shorter 3/8" SDS bits.

Are there any collet systems in existence that can be tightened by hand...

“The nice thing about the hurricane is that the longer locknut comes real close to the wrench flats. Helps level out the drill.”

Edit: Eric what are your thoughts on heat treatment?
So if that was the base price par the collet holder and lock nut, you would still need to add grips, 2 swages, 3/32" cable, PVC tube, Collet, grip glue, Hardened insert, heat treatment and time.

Just seeing howtotal cost would compare to a hurricane.

“I propose that the Hurricanes (D5 Drill) be the one to go with as it is all set up and ready to go.”

All this collet chat has me wondering: Can anyone place a link to the type of collet you would use in a Hurricane Drill as currently designed? I have one but have no idea where to get collets for different size bits.

http://www1.mscdirect.com/CGI/GSDRVSM?PMTYPE=KEY&SISMNO=18557730&SISHNO=0&SIZZNO=70580037&SISRCH=1&SILEVL=2&SILSEQ=3&SIT4NO=99662410&SISRC=KG

Look for 200DA or DA200 type - there are a large number of sizes listed.

“…In fact the ER collet will actually pull it in slightly when tightening, so there should be a bit of pressure between the bolt and the drill once it's tightened. Which leads to my next thought, which is that if the bolt is bearing directly on the drill there isn't much reason for so much meat on the collet chuck shank.”

Aric, I’m not sure I completely follow what you are saying. With stuck bit problems that arise from time to time when using dull bits, as described above, I think it’s good that the collet grab as much of the bit as possible so that the bit is less likely to spin in the holder should a wrench be needed to torque a stuck bit loose. Does that make sense, or am I on a different page?

With your drill holder design, a pre-made cable wrist-loop could be swapped out for a damaged one, simply by removing the grade-8 bolt, switching the wrist-loops, and then replacing the grade 8-bolt. To replace a damaged wrist-loop on a Hurricane, a swager setup is needed.

If there are no wrench flats on the holder itself, then one wrench is used on the hex end of the grade-8 bolt and one on the collet nut, in order to tighten the collet, correct?

Does the grade-8 bolt need to be doused in red loctite to prevent it from loosening before the collet nut loosens, when trying to remove a drill bit? If the collet nut is tighter than the grade-8 bolt, then the bolt will loosen before the collet nut loosens, meaning that you can’t get the bit out of the holder. Yes? No?

“One thing I neglected to mention is that the socket for the collet has a hard stop at the end, which provides a solid connection between the shaft and drill for increased efficiency while hammering (and hopefully less tenancy for loosening of the nut/collet).”

“A picture _AND_ a thousand words!”

“EDIT- Actually, it looks like Theron spec'd 4340 @ HRC46-48 for the D5 hammers, so it would probably work just fine for the striking face if dropped down a bit to something like HRC35-40. Unless you have another suggestion I think that's the way I'll go with it.”

Will the ID/OD tolerances be tight enough on the striking piece and shank such that the end of the shank cannot mushroom within the striking piece, making it very difficult to remove?

With respect to vibration dampening...

One thing that might be of concern is the thinner cross-section of the shank....

HRC35-40 seems pretty soft, but if the piece is replaceable, then why create additional wear to the hammer?

I think the BD hammer is too soft...

What’s the hardness of the insert in the Hurricane? And, what, approximately, does H900 in stainless translate to in HRC, for say, 4130, if that makes sense? From insert, to holder, to hammer… what kind of hardness range are we talking about?

And SDS... how about Students for a Democratic Society?

“By going with the lazer cutting, we could have a double ended set up and have a custom size. One end for the drill and the other for bolts.”

“Shown is a 3/8 and a 1/4 ER16 collet.”

“I need to get a 1/4 collet for my drill.”

“The SDS bit was developed by Bosch in 1975 and the name comes from the German "Steck – Dreh – Sitz" (Insert – Twist – Stay). German-speaking countries may use "Spannen durch System" (Clamping System), though Bosch uses "Special Direct System" for international purposes.”

“Overall it's 4.80" long and should come in ~10 ounces with collet and leash.”

A few questions: ....

OK, I thought those were wrench flats behind the collet nut threads but wondered about access, considering the grip. Looks like the grip has to be pulled just about all the way off to replace the striking piece, or to tighten it up.

Is there enough clearance on the grip such that the collet nut and collet can be easily removed, without messing with the grip?

If a bit becomes stuck in the rock and a wrench is required on the drill holder, the holder should be cranked in a clockwise direction, to avoid loosening the striking piece. (EDIT: I guess you could also use a wrench on the collet nut to loosen a stuck bit, but would then have to turn the wrench in a counter-clockwise direction in order to keep the collet nut tight on the holder.)

Still wondering if the grip will stay put without any sort of glue. But that’s where the fun part comes in – testing!

Thanks, Aric!

“It's hard to tell in that pic, but yup, the flats on the collet nut are fully exposed when the grip/sleeve is in the forward position. Here's a view that makes it clearer...”

I’m wondering… if the collet nut is completely removed, is it difficult to get the collet out of the holder because it is recessed within the rubber grip, or does it pop right out?

So, I assume that the tag hole washer sits loose, in the ~1/4” slot between the flange of the aluminum sleeve and the flange of the striking piece. Yes?

So um.... without sounding like a prick but.... um.....do you guys have like an extended warranty on this rig?

If you try to pound a 3/8” 5-piece into a hole drilled with a 3/8” HSS bit, you will also have problems. The hole is again too tight and the cone may get stuck. A 25/64” HSS bit is required for proper hole diameter.

“In an attempt to protect the threads from deforming the end of the shaft is turned down to a smaller diameter, which is a tight fit into a corresponding recess in the striking piece.”

“There's also a small fillet around the underside of the striking piece, which should help strengthen the joint as well.”

“If you were going to size up from 25/64 for an HSS bit, what size, smaller than .400, would you pick?”

Maybe something metric? I dunno. The next step up from 25/64” would be 13/32” but that translates to .406”, which is apparently a hair too big for the 5-piece cone.

In an attempt to protect the threads from deforming the end of the shaft is turned down to a smaller diameter, which is a tight fit into a corresponding recess in the striking piece.

The "tight fit into corresponding recess" is asking for trouble. This will almost certainly swage together permanently under the impact. Ditto the threads if they are tight. Your idea is in the right direction. The diametrical clearance should at least be a loose fit.

Other possibilities: combine loose cut threads (minimize load bearing surface) with a broad (30 - 45 degrees?) conical taper mating surface. Your loctite will hold the striker in.

Or do you mean to never remove the striker? In which case forget what I just said.

As a mechanical engineer I'd be worried about stress risers at all corners. Have a generous radius on all load bearing inside corners and a 45 degree chamfer on all outside corners. Not shown on your drawings.

I imagine you'll be going through 2 or 3 design changes and will need lots of field testers.

I'm surprised how soft the BD hammer head was. Theron is making the D5 hammers about 46 RC, same as your good ball peen hammers. Got another BD to test?

Your striker should be somewhat less (obviously). I'd make all the other impact bearing components at least hammer hard. For the intended use I don't see what advantages stainless steel has over tool steel except it looks prettier longer.

Lots of Monday Morning quarterbacking from me.

Caveat Emptor: I'm not a rock drilling expert, actually a novice.

“And seeing as ER collets aren't available in stainless anyway…”

Hmmmm.

The DA series collets (Hurricane) are stainless, correct?

Yeah, I missed the bump too.