Thread: Hammer A3 31 Torx screw problem - won't come out

Originally Posted by Pat

Brett, you "set" the bit with a percussive device and then use a 1/4 socket or ring spanner to back the screw out . . . Righty tighty . . .

They are supposed to be set to xxNm (Chris Parks knows the number, and he has a special torx T-wrench for it). I was talking to a Felder guy on Saturday at the Sturt show and described my method of finding the unscrewing clutch number, and then using that number to re-tighten. He liked it. The problem with this last screw is that it has obviously been bruted on - all the others cam off with clutch 11 or 12. I think there might have a couple that required 13 or 14. They were all re-tightened with clutch 9.

Anyhoo, I'll pick up some more bits from somewhere tomorrow, and try some more techniques (hammer, socket, and then heat if required) when I get back. I'll try to get some non-Sutton bits because I have a suspicion that they are just a bit too cheesy for the job.

Thanks to all for the input thus far.

I’m with Rustynail re the wack! If you don’t want to hit the bit, you can use a parallel punch on the head of the faster and hit that with the hammer. One or two good hits only as you can damage the torx hole shape.
i would then use the Torx bit in a ratchet or other hand operated item rather than keep using the electric impact driver.
If all else fails, see if you can find a mechanical impact driver and use that - one hit gives a downward wack plus a slight rotational force at the same time, rather than a rapid, repeated wack from the electric impact.

Brett, I wrecked 3 separate T-20 T handled drivers rotating the cutters on the club Thicky

I think it is the combination of the size of the head and over tightening.

My suspicion is that it's rusted in the thread, I've had a few do that but the impact gets them out.

4 years of rust would have it pretty well seized, try the torch and then immediately quench the hot screw with WD40 or similar

Originally Posted by elanjacobs

My suspicion is that it's rusted in the thread, I've had a few do that but the impact gets them out.

4 years of rust would have it pretty well seized, try the torch and then immediately quench the hot screw with WD40 or similar

It may be, but it's the only one of the 63, and I just don't have a general rust problem up here. The humidity is almost always very low. My planes and chisels hang on a board exposed to the atmosphere of the shed and there is nil rust to speak of. (I was actually concerned last week because I hadn't checked some of them for rust in perhaps a year - nuthin there though).


The only thing that concerns me about whacking the bit with a hammer is the brittleness of TC. Perhaps it's not an issue as the screw can't actually move more than perhaps microns. However, I do have a full set of replacement cutters +10 as spares.

We don't have a rust problem either, but a few random screws are rusted in. The offending holes tend to have some swarf at the bottom from tapping the thread that didn't get cleared out before the inserts were installed at the factory.

The torque number is 24 thingos (I'll have to check) and bike shops sell a pre set tool that sets them to that figure, there are several different types on this page
wiggle.com.au | Topeak Compact Torque Wrench | Workshop Tools

I will drop a proper impact gun over to you in the morning if you want, if it doesn't move it nothing will. The other obvious thing to do is cover the cutter with a rag and break it from under the clamping screw using a hammer and chisel and then the torque will be off the screw. If it has been done up as hard as it seems then it might be good idea to replace it as the threads could be stretched in the screw. Don't worry about a tension wrench as I have one you can use.

I think I'll try the candle trick, plus using the impact driver to tighten a tiny bit. Sometime when you do that, it actually breaks the seal and then you can undo it afterwards.

Originally Posted by FenceFurniture

They are supposed to be set to xxNm (Chris Parks knows the number, and he has a special torx T-wrench for it). I was talking to a Felder guy on Saturday at the Sturt show and described my method of finding the unscrewing clutch number, and then using that number to re-tighten. He liked it. The problem with this last screw is that it has obviously been bruted on - all the others cam off with clutch 11 or 12. I think there might have a couple that required 13 or 14. They were all re-tightened with clutch 9.

Anyhoo, I'll pick up some more bits from somewhere tomorrow, and try some more techniques (hammer, socket, and then heat if required) when I get back. I'll try to get some non-Sutton bits because I have a suspicion that they are just a bit too cheesy for the job.

Thanks to all for the input thus far.

That is not a good method. Once the screw is tightened to a torque figure it takes more than that torque number to release it for a whole lot of reasons. That is why when the figures for an impact gun are looked at the unscrewing torque exceeds the number it will tighten a fastener to and usually by a good margin.

Brett, I am horrified at your methods. Firstly, use PB Blaster to release the screw.

PB B’laster Penetrant | The B'laster Corporation

https://www.ebay.com.au/itm/PB-Blast...MAAOSwLEtYfuH1

Secondly, put away your power drill and only use a torque wrench. I use one with the correct torque setting.

I have turned all my faces, and they were tight, but opened up without a fight. They went back at the correct torque.

Regards from Perth

Derek

Originally Posted by Chris Parks

That is not a good method. Once the screw is tightened to a torque figure it takes more than that torque number to release it for a whole lot of reasons. That is why when the figures for an impact gun are looked at the unscrewing torque exceeds the number it will tighten a fastener to and usually by a good margin.

Well I have been using "9" to re-tighten, and had cause to change a couple to a different position on the head. They came off with 9, but I think I had to use 10 for one of them. This is less than i had to use for quite a few when first undoing them, so the torque must be reasonable, I would have thought.

Just heat it up and give it a sharp whack with a hammer while the Torx bit is in it.

Worst case, just use a nail punch on the size of the CT bit and shatter it. If your replacements are slightly off or leave a line, take a bit from the outside of the head and put it in the middle.... put the new one of the side.

Once you get the wretched thing out, here's a neat tip I got from an old car mechanic but it only works on bare steel.
Before you replace the screws, remove any oil, penetrant etc and paint the threads with a concentrated CuSO4 solution and let it sit for at least 10 minutes. This will precipitate a layer of metallic copper onto any bare steel parts of the threads and makes it a lot easier to remove next time. I have sometimes cleaned the screws and dropped them into some conc CuSO4.

Originally Posted by derekcohen

Brett, I am horrified at your methods....
Secondly, put away your power drill and only use a torque wrench.

Prepare to be horrified some more.

Torque wrenches are 100% not necessary here.

The torque numbers are non-critical and firm hand tight will do just fine. I have done thousands of inserts with an impact driver to the precise torque of "a few clunks" and have never snapped a bit or cracked an insert. Just go slowly with the driver and there's no issue.