Bridgeport for Beginners!

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So the dirty old yuasa 550-007 is giving me the stink eye so I decided to rip her apart for a clean and lube. Found an old fart on YT with a very similar cushman that was invaluable for ripping it down. Thank god for YT some days. Now I'm down to the 3jaw chuck. I've pulled every screw and the 3 gears out of it. what's the magic word to get this last bit apart?



is this one of those where you screw into these holes and jack it off by tightening?
Or should I hammer on the scroll ring from the other side?? I dont really wanna F this up. thanks!

 

Assembled by bozo the clown!


I'm pointing at number one. I catch the scroll as it goes by and the same for 2 and 3. My number 3 is missing its first tooth on its jaw so I let the scroll pass one revolution. Strange, how number 1 beats 2 and 3 to the center.. Wonder if you can still get parts. New this thing is a couple of grand!

FWIW, I learned where those rings go on this thing! I've got 6 of them. Pretty cool how it works.

 

TA DAAA! Turns out 1 is ALSO missing its first tooth! How does this stuff happen? Probably doesn't matter at the end of the day. Not like this thing is spinning it's ass off. As long as they meet in the middle and can hold something, I bet it's good. Besides, new ones are STUPID money.

 

It is sometimes a progression of threads and they get damaged or fixed. Sometimes the fix is wash them out with a 90° do-more grinder. I personally don’t like it, but I do work with it, Or I will make it work. Pick up Pitch needs to be uniform. Timing of a disk/scroll plate thread to 3 jaws, needs to be uniform. Tracking needs to be identified. This is the 1,2,3.

Truing the jaws after proper tracking is a little more advanced but soft jaw applications will get you into truing Jaw applications.

Understand concentric before you chase the rabbit hole of soft jaws.

 

"do-More grinder" lol That's a good one and an idea. Just lose #2's first tooth. Not really a big deal I suppose as long as I remember this issue when installing them. Got any clue how to get the chuck apart to clean the hard grease out of it?

 

The scroll plate does come out. Usually there is 3-4 screws and two dowels. Make sure you pull the dowels first. more pictures of the back of the chuck would be helpful.

Sometimes the dowels can be set screw locked with half blind through hole,also known as a dowel seat. The drilled hole is through, but reamed to a depth/shoulder. They only knock out one way. Most modern machinery never has tapered dowels anymore.

 

ahhh... I bet these are them. There are 3 of then, each accessible I believe through the gear holes.

 

The pins came out easy. Short little suckers. It's still tight and nothing is moving.
They pushed THROUGH from inside to outside the chuck. Didn't see that one coming.
You were right, they only go one way.

 

Shes moving!! It requires to be jacked off with 3 screws. Gold star for you Matt! Thanks buddy!

 

Nasty! Too bad you cant SMELL this thing! I'm glad I'm taking the time to open this up.
I'm probably adding years to it's life.

 

In Post #249, The little bits in your hand look like they are broken off dog screws. A dog screw is somewhat of a nominal dowel that is turned the lead of a screw (one size under the root diameter).

This is a dog setscrew. 1/4-28 with 3/16 x 3/16 dog.

 

I also hope you made a mark for lineup location. Good chances being, that back plate will only lineup one way. The dowels you can mix them up. But the hole to hole alignment has to be put together the same way it was taken apart.

 

Thanks Matt... No dog screws on the pins. Just pins, they tappy tap tap easily right out the gear hole. (probably called a pinion)
Yes I marked them! I bet they only go back together one way.

 

I got this little prick outta there. Took a few tries and it has to be lined up perfectly. Best 12bucks I've ever spent on a handful of magnets. That magnet cannot be any larger than 1/4" in diameter or it will never fit. I suggest 1 inch in length at a minimum.



Making progress on this thing. Lots of scrubbing, but it's coming back. Needs a coat of paint.
Doesn't smell anymore.

 

Jason you're in a world of hurt when your wife finds out that you're using the good white bath towels to protect that barstool. Almost no amount of bleach will fix that!

 

lol.. I'll wash it in some avgas. That stuff will clean anything!

 

You know the discoverer of Tetra Ethyl lead for use as an octane booster, Thomas Midgely held a 1924 press conference to show the safety of the stuff after several workers in the chemical plant went insane and five died in the first two months of operation. Thomas washed his hands with the stuff and sniffed it, and promptly after, had to take time off from work due to lead poisoning and was relieved of his position at the company making the stuff in 1925. Tetraethyl lead could be patented as an octane booster but ethanol which was tested by the US Army for use in gasoline could not.

Thomas is also responsible for the invention of freon gas for use in refrigerators whereas butane which works just as well could not be patented. There are modern fridges that use about a cigarette lighter's worth of butane gas to run.

Speaking of rags, I scored a couple of ute loads of cotton sheets and towels from a hotel laundry company that went bust. I try and use them several times each before they get used for soaking up oil spills or greasy stuff. The towels just get washed all the time and stay at a fixed level of stain but still work ok in the workshop.

 

Interesting stuff Mark.
So ya saying I should stop bathing in the stuff? They have been trying to outlaw avgas for years. Kinda tough to tell the average airplane owner they need to spend 50grand to dump their engine just to keep the tree huggers happy. Personally, I love the stuff. When it evaporates out of equipment such as lawnmowers and carburetors, it doesnt gum up and I've never seen it turn to varnish. It will however collect water like no bodies business. I've flown some piston aircraft converted to run on automotive gas and they are DISGUSTING! That smell never goes away. I hope they never outlaw 100LL.

 

Yep keep using it but don't smell it or lather it all over your arms. E85 or 85% ethanol is 108 octane so I expect engines could run off the stuff so long as the fuel system seals are compatible. Pure toluene thinner is 114 octane and fuel system compatible, i think it's used as a booster for lead free fuel. The only problem with ethanol is the energy content is lower so less range.

As a kid one of my jobs was to get a sharpened hacksaw blade and scrape yellow lead oxide and metallic lead out of used aeroplane spark plugs, then give em a blast on the Champion plug blaster, regap them on an arbor press and give em a test on the Champion.