Bridgeport for Beginners!

Thought it was time to toss something in the thread here. I picked up some cheap indicators and made these two handy tools.
Pete, my youtube shop teacher told me I should make these! What a good student I am!

After you calibrate this, it makes tramming in a head a breeze and highly accurate! In addition, it could also be used with a sine bar
to setup angles too! ( I almost sound like I know what I'm talking about! )



And a handy tool for the lathe too! This is a smaller indicator, funny how they cost way more than it's bigger brother.

 

More of a lathe question and I am still sorting this taper thing out in my head I have something that has pissed me off enough I want to deal with.
Here is my jacobs chuck with an MT3 stuck in it. It works well in my tailstock as it should. The manual says it's MT3. So far so good.
Now I have a nice running live center that came with the machine. While it fits the tail stock fine and works well, it doesn't do the extendo trick when I retract
the tail stock. So to get it out, I always have to whack it with a rubber mallet. Is there anything that can be done with this live center like change some part of
it or am I just stuck with this method until I get another live center??? What's the deal with the tang? I see some MT3 with it and others without? What gives?
Thanks!
On a good note, I found a really nice little 11n Jacobs chuck in great condition that came with the lathe. I learned it's a 2jt and found a 2jt to MT3 thingamabobber on fleabay.
Now I can put it to work. Wonderful!

Live center at the top. Looks like it's one piece to me. I can't see how it would come apart. Is that possible?




Ass end of live center. I think there is a bearing in there, but no screw or hex. :-/


Front of live center with pointy thing removed. Nothing there either.


Nice little 11n chuck. I like finding crap some poor sap ponied up the bucks for. If it's free, it's for me! I'll take THREE!
Behind the chuck is a bunch of airplane jack tops.

 

Found a great page here on Morse tapers for anyone scratching the itch. http://www.beautifuliron.com/mttaper.htm

 

Your live center might be like mine and have a small parallel roller bearing in the morse taper end. You may be missing an end cap over that bearing with the feature that ensures it ejects from the tailstock. I have a similar live center and it was threaded for a bolt so I put a slotted dome head screw in there so it comes out.

 

Good idea Mark. I cant really see it being that hard to make some kind of plug for the back end there so the pusher ejects it. This live center is silk smooth, but I imagine I'm not doing it any favors beating it's ass out of my tail stock each time I remove it.

 

A short term fix is a bit of hard wood or plastic that wedges between the live center and the tailstock casting as the tailstock quill is withdrawn into the iron housing. For me it's a strip of soft 1/4" thick aluminium extrusion that catches the live center as the tailstock quill is cranked into the tailstock (hope this makes sense).

 

My Live center was too short for my SB to eject it as well. It's an import and has no provisions for a cap so I just epoxied a nut to the end of it. Just something for the ejector to push on.

 

You have a lathe, just machine up an end piece. I'm guessing an inch or less will bottom out the tail. 80 thou under the taper and press fit?

 

Perfect! I'll get the engineering dept on a fix this afternoon!

 

Ok. So mines not as pretty, but it works great ejecting the live center! Thanks guys. Nice fix for a bullshit annoying problem.

 

Amazing what you can do when you have the machines to do it I'm just getting pee'd off with the mill being tied up by one of our guys 'oh it's set up to do this job' which has taken about a week so far and hasn't even happened........

 

Very true mate! If a guy has a mill and a lathe, giving enough time, skills and materials, a bloke can make just about anything. Not being too reliant on others is always a good thing!

I figure if this aluminum plug has an issue, I'll make a steel version. Seems people are on the fence how much work this thing does preventing it slipping in the tapper.

 

I've got the exact issue with a drill chuck. I had cut the tang off because my clausing mill manual recommends not putting a tang-ed taper in it (not sure why) and now it's too short to eject from the lathe tailstock. I'm thinking I can cut that taper shorter, drill and tap for 3/8 threads, and add a screw-on extension. Then I can utilize the threads to fit a drawbar when using it on the mill. Currently the taper friction is the only thing that holds it in the mill, and it doesn't spin (yet), but it seems like a good idea. I rarely use the mill for drilling unless it's a standard collet sized fit, but when I do mount up the drill chuck I raise and lower the knee instead of utilizing the head gears. They are notoriously delicate in that machine, have been repaired before, and I think one of them might even be broken again.
But, while I'm here.... That Jacobs chuck I mentioned above does not run true. It's not loose and does not appear to be worn out. Any tips on diagnosing?

Pete

 

You might try to remove your Jacob's off its taper attachment and reinstalling it. Maybe it got cockeyed when someone installed it? If it's still out of whack, you can buy MT tapers stuff cheap online. The MT3 to 2jt cost me 10bucks on fleabay. At least those are replaceable unlike the taper on my live center.

 

I know this is REALLY LAME, but why not?? 3/8"-16 using the blondihacks single point beginner method.
Baby steps!

 

Woohoo!, there's no turning back now!.

 

Hey mark. So this was a 3/8" thread and I started with a diameter of .373 Blondi said to go 2thou undersize, chamfer the end and start threading until the blue was almost gone.
Is this good standard practice to shoot for? My nut here threads on beautiful and when I try to wiggle it, there is no discernible slop on the nut. Sound right?

 

Any hardware store rolled steel bolt is always undersize on the major diameter (outside diameter)of the thread. What I do is go bang on the correct diameter, thread it until the thread depth is getting close and measure the minor diameter with the sharp tips of the digital calipers (ballpark figure). The crests should still be a bit flat on top, not a razor sharp edge and start testing the sample nut to see if it threads on half a turn or so. A triangle file can be used to round off the crest and put a fine radius on the thread crest, I have had a sample nut go from only threading on half a turn to fully threading on the cut thread with a small amount of filing the rotating thread crest to radius it with a few gentle strokes. I use a fine triangle file 10" long with a handle on it so it can't stab you in the wrist if it digs in and gets flicked out (described in lathe safety articles). The 60 degree file can also knock off any fine irregularities or slight tears you get when threading on steel while machining metric thread flanks.

No wiggle is pretty darn good when you compared it with mass produced hardware.

 

Gotcha! I'll try going bang on next time when I try to make a matching internal thread. I got some carbide threading tools. No way am I shaping jack squat if I dont have to.