This chuck needs some TLC because the activation lever is far too stiff to use. Once thrown, it has reasonable (but not stunning) holding power, so it's worth seeing if the chuck can be resurrected instead of replacing it.
Some views of the chuck as found.
Although the nameplate has been sanded clean of almost all the paint/ink, some googling around turned up chucks with enough similarities to this one to establish it as having been made by Eclipse, a UK company. Good to know since it may mean metric fasteners, etc.
Some views of the chuck as found.
Although the nameplate has been sanded clean of almost all the paint/ink, some googling around turned up chucks with enough similarities to this one to establish it as having been made by Eclipse, a UK company. Good to know since it may mean metric fasteners, etc.
Filled all the recesses for the screw heads with Kroil and let it soak for a few days while I waited for the 1/2" & ~3/8" wide screwdriver bits to arrive.
Oil port plug came out easily with Kroil and the 1/2" wide screwdriver bit. I had to reduce the thickness of the bit at the tip to make it fit the slot.
Plug is threaded M13 x 1.5mm Note ragged rim of tapped hole and chewed up crush washer. Not too surprising, then, that the inside of the chuck is bone dry. Maybe just rinsing out any residual crud and refilling the chuck with oil will be enough to loosen things up and I can avoid the question of "to open or not to open". Need to fix things up so the plug will seal again. |
Oil port after clean up with a fine grinding stone point and an extra fine (gray green) Cratex point in the flex shaft. Had to stuff a rag into the port and then vacuum up the grinding swarf before removing the rag to keep the swarf out of the chuck. Not a beautiful sealing surface, but light years ahead of where it started. If it still doesn't seal well, I can always do more work on it. If that doesn' do it, there's always Permatex. |
Plug and port cleaned up with new copper crush washer ready to go.
Washer came out of an assortment from Harbor Freight. 12mm ID x 18mm OD x 1mm(?) thick. The old aluminum washer was M13-ish x 18mm-ish but it's hard to tell given how chewed up it was. The new copper washer was opened up with a half-round needle file and a flap sander until it fit over the M13 threads. |
Next step was to try to clean out any residual gunk in the chuck prior to filling it with new oil. I poured in about a cup of WD-40 and sloshed it around. That amount didn't fill the chuck body completely but it was plenty to make gurgling noises as I turned the chuck on and off repeatedly. Initial hopes of the chuck acutation becomeing miraculously better after the intro of some sort of lubricant were dashed. The lever works a little more easily, but it's still very stiff. I replaced the plug using the old mashed up Al crush washer just to see if it would seal. It did, as far as any gross leaks anyway. After flipping the chuck over right way up, I cycled the chuck a bunch more. No real change. |
I chose 140 wt gear oil based on information in a post by Malc-Y on homeshopmachinist.net. There he gave the following specification for oil as having come from Eclipse:
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"Specific gravity at 60 degrees F (15.6 degrees C) 0.924
Open flash point 525 degrees F (273 degrees C) Redwood viscosity No.1 at 70 degrees F (21 degrees C) 10,000 secs 100 degrees F (37.7 degrees C) 2,700 secs 140 degrees F (60 degrees C) 720 secs 200 degrees F (93 degrees C) 176 secs Kinematic viscosity 100 degrees F (37.7 degrees C) 693 centistokes 210 degrees F (99 degrees C) 34.7 centistokes" |
According to this table from The Dolittle Oil Company, Inc. website, 693 cSt at 40˚C is at the upper end of the kinematic viscosity spec range for SAE 140 gear oil. |