Auto Doc's
Well-Known Member
- Joined
- Sep 7, 2024
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Hello All,
One of the most frustrating fasteners to deal with can be an Allen head retainer screw. They are often recessed down deep into the holes of pulleys and control handles.
Soaking overnight with "Panther Piss" helps but can often take days to creep into the rust and soften it. Much worse than the rust is these screws often have a tapered point tip design with a "grip cup" at the end. This ensures they "Bite" into the shaft the component is being attached to.
I had one such example over the weekend on a John Deere 757 zero turn deck adjuster knob. It had a very stuck 3mm Allen wrench size set screw down in a recess area.
I tried the typical soaking and pliers on the end of the Allen wrench, but this thing not going to give. When I put a 10mm box end wrench on the "L" of the Allen, I could watch the thin wrench shaft begin to twist and that was not good. (I don't used cheap Allen wrenches)
What I ended up doing was using the 10mm box end wrench to apply mild twisting leverage to the "L" end of the Allen wrench on the screw, then at the same time I used a 12oz ball peen hammer on top of the turn knob to firmly strike (Shock) it. After about 3 firm hits, the screw broke loose. From there I just kept soaking it and turning back and forth until I could lift the knob off the shaft with a few "love taps" on the underside of the knob.
Later in the day, I had a V-pulley on an engine shaft that was badly stuck in a similar way. I resorted to using and air hammer with a blunt punch bit so I would not break the pulley flange. Just using steady pressure on the Allen wrench and shocking it with the air hammer bit worked like a charm.
The Allen fasteners used on pulleys and handles design has been around for many years because it is so reliable.
My point of this post is to let people know that they have to think about how an Allen screw physically holds. When you run into one, you are not just contending with tight, rusted threads, you are also fighting to loosen the pinning force of the tight Allen screw to the shaft. By "shocking" the component in the area around the Allen screw it persuades it to let go so the threads of the screw can finally turn to back the screw out.
If you don't have an air hammer, any decent hammer and a dull punch will work well for "shocking" the component so the Allen screw(s) will loosen.
I've rounded out Allen screws and likely broke a drawer full Allen wrench in years past before I started using this approach.
One of the most frustrating fasteners to deal with can be an Allen head retainer screw. They are often recessed down deep into the holes of pulleys and control handles.
Soaking overnight with "Panther Piss" helps but can often take days to creep into the rust and soften it. Much worse than the rust is these screws often have a tapered point tip design with a "grip cup" at the end. This ensures they "Bite" into the shaft the component is being attached to.
I had one such example over the weekend on a John Deere 757 zero turn deck adjuster knob. It had a very stuck 3mm Allen wrench size set screw down in a recess area.
I tried the typical soaking and pliers on the end of the Allen wrench, but this thing not going to give. When I put a 10mm box end wrench on the "L" of the Allen, I could watch the thin wrench shaft begin to twist and that was not good. (I don't used cheap Allen wrenches)
What I ended up doing was using the 10mm box end wrench to apply mild twisting leverage to the "L" end of the Allen wrench on the screw, then at the same time I used a 12oz ball peen hammer on top of the turn knob to firmly strike (Shock) it. After about 3 firm hits, the screw broke loose. From there I just kept soaking it and turning back and forth until I could lift the knob off the shaft with a few "love taps" on the underside of the knob.
Later in the day, I had a V-pulley on an engine shaft that was badly stuck in a similar way. I resorted to using and air hammer with a blunt punch bit so I would not break the pulley flange. Just using steady pressure on the Allen wrench and shocking it with the air hammer bit worked like a charm.
The Allen fasteners used on pulleys and handles design has been around for many years because it is so reliable.
My point of this post is to let people know that they have to think about how an Allen screw physically holds. When you run into one, you are not just contending with tight, rusted threads, you are also fighting to loosen the pinning force of the tight Allen screw to the shaft. By "shocking" the component in the area around the Allen screw it persuades it to let go so the threads of the screw can finally turn to back the screw out.
If you don't have an air hammer, any decent hammer and a dull punch will work well for "shocking" the component so the Allen screw(s) will loosen.
I've rounded out Allen screws and likely broke a drawer full Allen wrench in years past before I started using this approach.