picked up a second Unimat SL and their is a a dead Center jammed in the tailstock ram.?
Tried really high quality oil to loosen, not budged so far. Held dead centre in bench vise soft jaws, still couldn¡¯t budge. Not much leverage mind since ram is out of tailstock. May have to reinstall ram in TS cast clamp tight and use for leverage with dead center held by vise¡? Anyone been here? Turns out tailstock ram is partly solid. thinking of heating the ram some hoping it expands faster than dead center and loosen that way¡ ?
Use a piece of ice, or dry ice if you can find it, heat the tailstock ram, and use the ice to cool the center. Or take the patient way, and spray it with copious amounts of WD-40, or PB Blaster, and let it sit. Try to twist it every now and then. If it give, great! If not, spray it again! Then wait a few hours and try to move it again. Twisting force is most likely to help. Back and forth until it comes loose. Might take a week or so of alternate spraying with penetrating oil or something to dissolve the rust that may have formed, and trying to move it. Took a couple of weeks on tailstock for my lathe hitting it with alternating WD-40 & PB-Blaster, and twisting the center.?
Guy who documented his travails with this on a larger lathe hung a weight off a lever clamped to the center, and eventually the spraying penetrating oil loosened it enough that one morning he came out to find the center had twisted from the hanging weight.?
You could cycle through both methods, if it's a really old, really stuck center.?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.?
SEMPER GUMBY!
Improvise, Adapt, and Overcome. Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better.
Expect in one hand, expectorate in the other. See which one gets full first.
On Monday, April 17, 2023 at 03:38:56 PM CDT, rcjge <jgpedwards@...> wrote:
Hey Folks
picked up a second Unimat SL and their is a a dead Center jammed in the tailstock ram.?
Tried really high quality oil to loosen, not budged so far. Held dead centre in bench vise soft jaws, still couldn¡¯t budge. Not much leverage mind since ram is out of tailstock. May have to reinstall ram in TS cast clamp tight and use for leverage with dead center held by vise¡? Anyone been here? Turns out tailstock ram is partly solid. thinking of heating the ram some hoping it expands faster than dead center and loosen that way¡ ?
Sometimes with these old machines the old oil drys and acts a bit like glue. Try soaking the part in petrol (gasoline) or paint thinners. This will dissolve the oil pretty quickly.
If it is still stuck its likely to be rusted in place. In that case try some heat to the outside.
Was actually thinking of drilling a small bore hole through from the back of the ram, and tapping it out with a small drift¡ Issue would be how hard is the ram itself gonna be, can it be easily drilled. It¡¯s probably surface hardened as it¡¯s a sliding surface, but perhaps not through?
Make 2 wedges approx 10¡ã? with a slot in the middle the same diameter as the? exposed dead center. Squeeze them towards each in a vise between the dead center head and the tailstock barrel and they will force the center out. Here is a video from Mr Pete showing everything. https://youtu.be/AtNM8-VUvrg
Bill in OKC too suggested : "... dry ice if you can find it ..."
Or, some electronics parts stores sell a spray-on cooling agent for testing the temperature behaviour of small electronic parts.? Some of these are quite good, although they might not induce as low a temperature as dry ice.? Sorry that I don't know the brand names or models of any of them, but one of them might be a good enough substitute for dry ice.
Anything that evaporates quickly will work in a pinch. A quick search for "spray cooler for electronics" brought up several from MG Chemical & others. Dad used ether cold starting spray a few times when I was a kid. Check Amazon, your local electronics store, et cetera. The spray coolers in the search won't leave a residue. Almost essential for electronics.
If so, you might be able to fit a metric grease zerk to it, and pump the tailstock ram full of grease, which would push the center out... Maybe. ;) It could get messy, and possibly shoot it and grease across the room.
Grip the center with vise grip pliers. Tap the pliers with small hammer. Center should pop right out. ?You can also use small flairing tool to grip center for same process.?
Good luck. -- Steve Jaynes Unimat owner/collector since 1995, all generations.
rcjge
Bill in OKC too
Unimat Matt
David James
Steve Jaynes