Drilling set screw



I've solved a lot of stuck fastener problems just by using a propane torch and a can of LPS 1. Heat, spray, heat, spray, repeat as needed. Sometimes it takes more than just a few go-arounds to get things loosened up. In this case, I'd be heating the hole area, not the fastener. Doesn't have to be red heat, just enough to expand things. Then there was the nazi superbolt in the VW shock mount, drilled that one out until it shucked the flutes off the drill, then spent three days with a mini-die grinder and a handful of pink aluminum oxide points grinding it out to the hole threads and picked the bits out with a dental pick. I've had the most success with left- hand bits on wood screws. Rusted bolts usually will drill or will break the drill bit, but don't move until they're cored out.
Stan
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On Wed, 28 Sep 2011 09:02:00 -0700 (PDT), snipped-for-privacy@prolynx.com wrote:

I hadn't thought of the die grinder solution. I may try that before the chip-it-out exercise.
Thanks
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On Thu, 29 Sep 2011 07:38:46 -0500 snipped-for-privacy@aol.com wrote:
<snip>

I used a Dremel #9911 Tungsten Carbide Bit - Diameter 1/8" to bore through a snapped off "easy-out" successfully. It was slow, hard going and a lot of sparks flew... But it gouged it out and amazingly (to me anyway) didn't look any worse for wear afterwards. This page (don't know anything about the supplier, just for reference) shows some of the bits offered by Dremel:
http://www.mytoolstore.com/dremel/tungcrbi.html
It looks like you have a better view of things too, mine was in an area where I couldn't see down the hole for more than a 1/4 inch or so. Had to listen and feel my way around grinding it out...
--
Leon Fisk
Grand Rapids MI/Zone 5b
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On 9/28/2011 2:47, Phil Kangas wrote:

Stainless will also rust, just a different "rust".. Happens especially easily when the body is normal steel and a stainless fastener touches the steel body. Anybody using same tools for normal steel and stainless knows how easy it is to get rust spots to stainless..
Still, propably a normal carbon steel setscrew..
One neat drilling solution is to used the normally ground drills that are made like masonry drills - with a tungsten carbide (or such) insert.. These will drill quite hard materials..
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snipped-for-privacy@snyder.on.ca wrote:

Maybe in Canada but in the UK A2 and A4 are commonly used for stainless steel fasteners with no s on the end. The UK designation for the air hardening tool steel was BA2 according to my link.

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On Sep 24, 10:48am, snipped-for-privacy@aol.com wrote:

I would not be considering heat since it is pretty easy to get to the set screw as as you say seals could make for an interesting search.
If you don't have a small carbide drill, then what about a small masonry drill with carbide tips? Check the local hardware store as ours has them down to 1/8" for drilling mirrors and tiles etc. Slow and steady and wd40 as cutting fluid.
Dave
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I wouldn't worry much about the seals.. there are lots of replacement styles, or even a greased leather washer (riding on a polished shaft) held by a sheetmetal retainer will work effectively at keeping dirt out. This is assuming that the lube is gear lube, not a hydro transmission (you said 1964 machine). You may still need torch heat to pull the hub, since the hub may not have been removed for decades.
The primary disadvantage is needing to use a handheld drill, which can attribute a lot to rapid drill point failure.. using a steady position and forceful feed pressure are going to be to your advantage. The drum should be secured so it can't rotate. If you can clamp a bar or other steady support nearby, it would likely help keep the proper approach angle and position.
In awkward positions and using a handheld drill, it can be worthwhile to take some time to fabricate a mechanism to apply more feed force and steady positioning using a lever to increase the feed force while offering a very steady feed direction.
In this situation, even a Cole drill wouldn't be a simple solution due to the drum size and the angle of the screw, but maybe something as simple as a section of chain and a lever pressing on the back of the drill motor would be appropriate.
The masonry drill suggestion could be a good solution, and for as cheap as they are, grinding them to suit your needs should make them even more effective for your needs. I'd suggest using a proper steel cutting lubricant, not just anything that's handy and slow RPM.
With a steady and forceful feed mechanism, using a pin and high RPM (no lubricant), friction may generate enough heat in the screw to soften it, but this method would likely be more appropriate for a workpiece on a drill press.
An air chisel used as a hammer, hitting on (a hex or mating) driver, with the hub supported by a steady hard backup like a jack stand on a cement floor (not a block of wood on soil) may be enough to work the screw loose while saturated with penetrant of ATF or miracle product. Hex wrench material and some hardened drivers are likely to shatter, so, the use of some fuel hose or other protective shroud would/should prevent shards of metal from shooting out and injuring the operator.. and uncommon sense should dictate the use of all the personal protection/safety devices/apparel required for safe practices. With a series of impacts the screw may dig into the key a bit more, relieving the holding grip in the key slot, and a couple/few thousanths inch of relief would be adequate to loosen the grip of ordinary square keystock, so a stable puller could pull the hub/drum off. Having the part removed from the axle will give you more options for dealing with the screw if it hasn't loosened to the point of just winding it out (or inward into the hole).
An annular cutter just larger than the screw diameter should effectively cut away the softer iron without dealing with the hardened screw. It looks as though you'd need to prepare a flat surface *like a counterbore around the screw hole) for the cutter to start on, with a die grinder (Dremel/Foredom etc).
I don't have a source handy, but these tiny holesaw-type cutters are available for cutting thru spot welds (although not particularly deep capacity) and other purposes. Woodworkers use similar centerless cutters for cutting plugs and dowels, so cutting cast iron with a quality cutting lubricant and slow speed may accomplish the desired results.
--
WB
.........


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On 9/25/2011 7:53 AM, Wild_Bill wrote:

If there is any way to get the correct bit in a hand operated impact tool, it would allow a quick tighten and loosen movement on the set screw. A tool like this: http://www.lislecorp.com/divisions/products/?product 1
I know you can get a 3/8 socket drive Allen bit which can be driven by the tool.
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That is what I've been using. Mine is a little more heavy duty; 1/2" drive. Of course, I have to use a 1/2 to 3/8 reducer so I may be losing some torque in the extra joint. I'm twisting the barrel in the pre-loaded direction. The allen size is 5/32 so I can't get too heavy handed.
I went out earlier and heated them; waited until they cooled and smacked them again. No joy. They are now soaking in PB Blaster again.
If they are not loosened by towmorrow, I'll start drilling again.
Thanks for all the suggestions.
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If you are using a handheld drill and not getting any chips out, your next best bet would be to (borrow one if you don't have one) use a benchtop drill press set up on blocks, at the correct angle so the quill downfeed would be constant and steady.
My box-store Ryobi ~10" benchtop could be set up in place, and definitely has enough power to drill those screws out.
Those little 5-speed $50 drill presses probably aren't any better than (or even as good as) a decent hand drill. A friend suggested I could use his 5-speed recently while doing some fabricating at his place, and it was essentially powerless, with a sharp 3/16" drill in mild steel.
A quality cobalt drill or masonry carbide (and a good cutting lubricant) should cut the screws with a steady, constant feed, which is often difficult to do with a handheld drill.
--
WB
.........


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On Thu, 29 Sep 2011 08:39:54 -0400, "Wild_Bill"

I have a big drill press but I don't see any way this is happening. the "piece" I'm working on is 4' long, the axle is 3' wide. The whole assembly weighs over 200#. The set screw is at about a 45 degree angle.
I'm using a 1/2" drill at slow speed. I'm able to really lean into it so I think the pressure is there, at least as much as should be put on 1/8 and 3/16 bits.
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Here's my strong vote for "heat and quench 3 times". I am sure you got the right idea from all the previous posts on this subject, but you need an OA torch with a really small tip, say a #1, in order to heat just the set screw. Get it glowing and have a squirt bottle of water handy. Once the set screw is glowing, squirt water on it until it is cool to the touch. Do this 3 times. Then, gently remove the set screw. A year or so ago I was faced with a couple dozen different kinds of stuck/broken off bolts in an Onan genset and I asked for help everyplace I could think of. The above was one of the suggestions I received late in the game and hadn't tried it myself until a few weeks ago. A guy brought in a front wheel drive car hub for bearing replacement. It had a sheet metal guard held on by 3 10-32 (or metric equivalent) screws that had been there since 1995. None of my normal stuff worked so I tried the above. It worked 3 out of 3 times. I am a convert. But, you have to be able to really focus the heat, I think. Note: one of the reasons you can heat the screw alone is that the rust/corrosion between the screw and the hub acts as an insulator so the screw heats faster than the hub (the hub having more mass). But, if you use too broad a flame, or a torch with a much lower flame temperature(think hardware store propane torch) the set screw will take longer to get glowing and the hub will be closer behind in temperature, so the set screw won't be crushing the rust as much.
See: http://www.spaco.org/MachineShop/StuckFasteners.html if you are interested in a range of solutions to this kind of problem. Long time lurkers: I haven't added to this page since Jan 23, 2010, when I posted its existence here.
Pete Stanaitis ---------------
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On Sat, 24 Sep 2011 12:48:04 -0500, snipped-for-privacy@aol.com wrote:

Update. After heating, more PB, let it cool, still won't budge. 1/4" masonry bit took off just a little bit. Used a 3/16 punch in the socket a few licks. The allen wrench still fit perfectly but it won't move even a little.
The carbide bits I'm finding are for masonry, hammer drills or spearpoint for glass and tile.
Maybe I'll continue heating and removing a little at a time
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snipped-for-privacy@aol.com wrote:
(...)

Can the assembly be submerged in a plastic bucket so you could use electrolytic derusting to fix the first- order problem?
Pete has a nice writeup here: http://www.spaco.org/Blacksmithing/Rust/ElectrolyticDerusting.htm
--Winston
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I understood the size/scale of the workpiece when it was described as a garden tractor.
My suggestion was to take a manageable size drill press to the tractor, and mounting/supporting it in a way that it could feed a drill steadily into the screw at the proper angle.
The same could also be accomplished with a Cole drill and some metal parts and clamps. Benchtop drill presses are generally more common than Cole drills. You could, possibly, borrow either type.
With either method, the drill feed could be from the top, bottom or sideways, whichever is more convenient. The mechanical advantage of a steady quill feed will create chips.
--
WB
.........


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