Loose fitting Torx/Star Security Bolts

[ccmdr]

Hi guys, before I start doing anything drastic and damaging my hub, does anyone have any experience with removing loctited and loose fitting/rounded T20 'Torx/Star Security' bolts, as google has failed me? This is by no means my first rounded bolt/screw, however I've yet to have issues with the Security type bolt, and the remaining 7 of 9 are stuck fast.

Had the common phase wire cut on HS3540 and trying to change the cables. I've purchased 'special' T20 titainium coated bits after my other ones shattered. Two bolts have come out with heavy lubrication and heating the hub. I've noticed however there is a clear type of loctite holding these bolts in. The bolt heads are sunken into the hub inhibiting any bolt extractor/socket/molegrip type attack.

Tried so far;
Lubrication soak - Heat - Hammer whilst turning - hub mounted nice and firmly on the horizontal axis with no means of escape = Two bolts removed
Modified my impact driver to fit Torx Security bits = Torx Bit twisted and warped... kind of expected that, shear ratings etc
On the worst fitting bolt 'encouraging' a T25 bit into place = need too much 'encouragment' to get a firm grip in the star
After the T25 tried the flatblade on its vertical/hammer rotation dance = just rounded one of the star points

Next action:
I can dremal a groove for a flat blade = hub damage
Attempt to drill out the Security Torx, although the pin in the middle of the star will create an offset hole = damage thread then retap...
Weld bolts onto the 7 stick bolts and try to remove = likely damage hub or worst case weld the stuck bolt to the hub

I'd like to shift the 'security pin' so a standard extraction is possible, but fear removing the pin via bend fatigue will just leave a smaller node to work around.

Any other ideas' from the mechanically minded?

 

[Drunkskunk]

Titanium coatings are only for tool longevity. It adds nothing for single use strength. What you need is just common hardened bits. They will be the dull black ones.

Welding the bits into the bolts would work, but I'd worry about the heat damaging the motor's magnets those bolt's shafts are less than 1mm from the back of the magnets. I wouldn't use heat to remove them for the same reason. It could also damage the glue holding the magnets. that's the kind of problem that might show up right away, or maybe not until next year.

I have not tried this, but you might try gluing the bits into the bolts with DP-420. Give it a few days to a week to cure all the way, then try.

 

[ccmdr]

Cheers Drunkskunk,

Believe I can liberate some DP-100 which seems to have a slightly higher shear rating 80-85, if I understand correctly.

I shall set, test and hopefully update positively in a weeks time.

Also, thank you for getting me to check the magnets integrity after semi successful heating attempt :wink:.

 

[Punx0r]

I would be *very* surprised if any kind of epoxy holds where a good quality torx bit has failed.

For those that round-out, I would grind the coating off the screw head with a dremel, place a hex nut over the head and weld it from the centre. It prevents damage to the surround material and the heat alone is usually enough to free off the stuck fastener (especially if there's Loctite). The heat from such a small amount of weld will easily be absorbed by the side cover and flux ring without heating the nearest magnet significantly.

 

[Drunkskunk]

I would be *very* surprised if any kind of epoxy holds where a good quality torx bit has failed.

The epoxy isn't to hold the bolt when it turns. The epoxy would be to fill in all the space left when a normal torx is inserted in the bolt cap. That will give a much larger surface area for the torx to apply pressure on, and hopefully let you put more pressure on the bolt before it strips.

 

[Punx0r]

Sorry, I did misunderstand you before. I'm still not optimistic it would work, though

 

[amberwolf]

Regarding the torx security pin in the center of the bolts, I've broken those out before on assorted kinds of casings to use a normal torx bit (because I didn't have that size security bit), using a small flatblade at an angle between the tip of the pin adn the side of the star, then whacking it with a hammer just hard enough to breakt he pin off (not very).

I don't know if that would help you at all, but it's a way I did it, long time back.

 

[ccmdr]

Cheers Guys,

amberwolf- I'll note that, the pins do seem excessively long and I've noticed the 'wear/purchase' marks on all 3 different type/brand of bits I've used are only 2mm, except the bit used with the impact driver 4mm.

Action plan - least destructive
Prep: Abrade and clean the bolt heads with IPA (the solvent not the ale :wink: )
1) I'll try the DP-100 scotch-weld first effectively 'adhering/welding' the bits to the bolts and filling the excess air gap.
2) Due to the shallow 'wear/purchase' marks, remove the centre pin and the DP-100 method.
3) Weld (Gasless hobby MIG is at hand) stainless steel M4 nuts from the threaded side to the stainless bolts.

@Punxor/All - I infrequently weld, shortening steel sidestands when turning enduro to sumo etc... These bolts appear to be stainless steel, although I have both stainless and your standard cheap steel M4 hex nuts. Am I right in assuuming I would need to purchase this type of stainless steel rod/wire or can I get away with utilizing the mild steel wire I already have?

 

[nutnspecial]

I like the idea of welding on the nut. I've welded mounts on my two bht motors and the case dissapates the heat quite well, although possibly some forced air cooling helped when I had the welder cranked up.

Does the bolt metal have any/much magnetic ability? I'm guessing if it's good quality ss there will be too much nickel and chrome for normal steel wire to work, but I never have tried it. A gasless mig uses flux core wire yes? I never heard of that in stainless, but with proper shielding gas, one could mig or tig it. It might be challenging to get the stud hot enough, but maybe brazing?

Hopefully epoxy and the bits work. Also, a true impact screwdriver might be better than air impact or electric drivers. http://www.ebay.com/itm/New-TEKTON-7-pc-1-2-in-Drive-Impact-Screwdriver-Set-2910-/111724556534?hash=item1a034d70f6:g:FkYAAMXQVT9TFlYP&item=111724556534&vxp=mtr

 

[speedmd]

Knock the center pins out as mentioned and drill the heads (only) out. They are soft and drill easy. Hopefully you have enough screw left to put a fresh toothed jaw vice grip on to get it out with out having to drill them. Heat (plumbers torch) will soften the loctite. Replace with good quality 10.9 screws.

 

[Punx0r]

Removing the head helps with bolts that won't turn because they are simply too tight: the tension in the thread is released and the remains are easily unwound. If the bolt is stuck because of corrosion or thread lock, though, I would not remove the head unless it's already mangled beyond use. While the head will take a tool it's probably your best chance of applying torque to the bolt.

That said, removing stuck fasteners is a subjective skill based on experience. One person will remove a stuck bolt in literally two minutes, while another person could spend several frustrating hours on it.

You can normally get a good-enough weld on stainless steel using mild wire and CO2 shielding gas

 

[Deafcat]

try a cold spray for loosening stuck bolts. works great in conjunction with heating parts... heat will expand aluminum particularly well and of course helps to loosen any threadlocking compound, get the female side warmed up with a heat gun then put a stainless sheet with a hole in it over the fastener for thermal deflection and blast the fastener with cold spray, and immediately give er a nice aggressive snap of torque with the required wrench. if it doesn't snap the head off you may succeed in removing it

 

[ccmdr]

Cheers for the info so far:

1) Failed instantly, the 3 bits were glued fast (24hr airing cupboard) with the correct mixing of DP-100. 1st with putting all my weight (ehm 60kg ) behind it slipped straight out. 2nd tried impact driver, again twisted bit. Its a mans driver which I use almost everyday at work, not an air or electric type.

2) Ha, the sodding pins are not soft. Flatblade has a nice big step in it now and the pin has barely budged a half mill. Tried drilling the security part of the torx bit to give better depth/purchase, but the same type HSS bits that worked fine drilling holes in an Akra Ti exhuast being repacked just get very, very warm (tip glowing).

3) Tried, but as the heads (8mm) are countersunk into the hub you have no external purchase. Placing the bolt on top, the thickness of the nut (3mm) and the thread of the nut create a convex shape that in the 3mm diameter hole inhibites the weld angle and the amount of fill needed. In the end the nuts were just fatigue/sheared off due to the 3mm purchase not the full 8mm with proper fill.

Tried filling the security torx head via weld to emulate a standard flush bolt head which has kind of worked, but the stainless is obviously much harder than the mild steel filler and the drill bits snagged on the pin and created an offset hole, which isn't cutting into the pin.

Dremaling the pins out is the next option and its going to damage the hub cover. Either that or use a large drill bit offset to center to 'drill' the pin away, which will make the cover completely useless.

I would never recommend security torx after this debarkle, yes allen or hex heads round off easier, but they take minutes to remove and 99% you don't need to sacrifice the surrounding area.

 

[speedmd]

It takes some luck and the correct shape tool to knock out the center pins. Worst case center punch it and drill (GOOD QUALITY BIT) at a suitable rpm. Once you weld or try to weld, your screwed unless you have carbide bits or a grinder that can get to it. Simple work. Frustrating learning however. Best luck with it.

 

[ecycler]

Will you take a few pics and let us know the end result to open that clam of a motor!? geez

 

[Punx0r]

Wow, seems like a stubborn job. Not being funny, but did you weld it HOT?

 

[ccmdr]

Again 'Punx0r' not a fabricator, welding skills go so far as if it passes the 'bash' or 'rubber mallet' test I'm happy .

Not overly sure by HOT, but the nut was glowing cherry red, like the colour you need to braze copper pipes together. I can't see the bolt head as it is countersunk and the tiny M4 nut completely obscures it. It's like trying to get the weld wire to touch the bottom edge of this nylock nut, you only really end up with 3mm of weld 'shaft' connecting the bolt head and the nut together.

Anyway to remove the pins from the center I used a 3mm HSS drill bit and used the star points and the pin as a guide, creating in effect a 'polo' shape on the head, this removed most of the weld 'filler'. Then with a 4mm HSS bit covered the same tracks and this took away the pin to a large extent, and a handy 'Stepped bit' (similar to this one) to start the process of cutting the head off completely.

'speedmd' your right, a carbide drill bit at the right speed is needed to overcome the hardness of the central pin, then with a pilot hole the stepped bit will do the rest and completely remove the head, all without damaging the hub . Only reason I'm using the stepped bit instead of a dedicated 10mm is the tip angle is similar to the chamfer angle of the countsunk head so I wont take an uneven amount of material from the hub once through the bolt head.

'ecycler' I have a mediocre phone at best and its picture taking ability is more for aesthetic purposes than actual function :lol:.

 

[Punx0r]

I only ask because the whole nut is usually orange by the time I've finished and I've not had the technique fail. However, I think the smallest nut I've tried it on was 6mm. I appreciate 4mm would be fiddly at best.

How far is the screw head sunk below the surface? If it's only a little bit I'd be tempered to lay a larger nut over the top (I.D. about the same as the screw head O.D.) and let the weld fill the gap. You might get a bit of damage to the surrounding aluminium, but it'd have a lot more purchase on the screw.

 

[ccmdr]

Update:

Carbide drill bits arrived today and worked a treat. Either or methods work for a Countersunk Security Torx/Star. As it'd attempted the nut weld, but the I.D of the nut was simply too small for the job. This worked for 8 bolts, although I did shear the head from one.

Pun0r's method of using a nut with a similar I.D to the nuts O.D. seems quite sound too!

Method 1
Step 1) Use a suitably sized HSS drill bit that fits between the star point and the center pin. Use the drill at an angle to got from star tip to star tip.
Step 2) Use a slightly bigger HSS drill bit to grind/drill away the remainder or the pin.
Step 3) Either use a high quality HSS or Carbide bit sized for your bolt extractor and centrally drill a 3-5mm deep hole.
Step 4) Hammer and rotate the extractor tool and all being well the bolt has either sheard the head or smoothly removing the bolt.

Method 2
Step 1) With a welder, suitably fill the Torx/Star head with a similar compound, steel for steel bolts etc...
Step 2) Grind the weld just enough to make it flat.
Step 3) Either use a high quality HSS or Carbide bit sized for your bolt extractor and centrally drill a 3-5mm deep hole.
Step 4) Hammer and rotate the extractor tool and all being well the bolt has either sheard the head or smoothly removing the bolt.

Now to squeeze 3 pieces of 12AWG Turnigy Silicone through the axel .

 

[ecycler]

Congrats on the successful clam opening! Make sure to clean to clean the magnet ring well in case any shavings made it down inside!
I had few problems stuffing 12awg teflon wire through a axle HS3540 recently. With that right wires, that will be child's play compared to what you just went through.

 

[ccmdr]

Cheers ecycler ,

That clam did it's best! Right at the bottom of the countersunk head one sheared. Couldn't nip it with anything, Carbide tip and a damn lot of luck and I managed to drill straight through the shaft of the bolt in the hub without damaging the threads . Was I a happy bunny, chest out, smug but unfortunately nobody to wind up :|. 'Did you see that! I'm GODLIKE!!!' fist pumping... Unreal Tournament unfortunately ingrained that.

The 12AWG only took 30 minutes, strip the 12AWG Turnigy Silicon bare, fit 3:1 6mm heatshrink, heat, solder to hub and connectors, check clearance in hub and voila. 1 week opening the hub for a 30 minute repair... Now to just replace the bearings.