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snowman
08-09-2004, 08:18 PM
Ok...I need to do a seeminly easy task. I need to machine the end of a piece of 1 1/4" CRS to 3/4" diameter, for a distance of 1.5"

The problem, it's on the end of a 24" piece of steel. I have tooling for a Mt3, my lathe is MT4...the tailstock is out of alignment, and I dont have a steady rest.

First, my normal method of aligning the tailstock is to put a ground mandrel between centers, then adjust tailstock until this is parallel with the carraige travel. I have lost my mandrel.

Second, I have no way of drilling a center hole in the end of the 24" CRS. If I had a steady rest, I'd chuck it up, "clamp it down" and drill the hole, then use my center as support to machine the end of the rod.

Any quick and dirty methods? My only thought is to get off my ass and make a steady rest because I need one anyway. Plus, I'm not too keen on paying 100+ bucks for one, which is what they seem to go for on Ebay.

-Jacob

yf
08-09-2004, 11:50 PM
Use a center head or hermaphrodite calipers to mark the center of the stock.

Center punch it.

Do the same to the other end.

Place a center drill in the headstock chuck.

Place a center in the tailstock quill.

Set the spindle to a speed suitable for the center drill.

Place the punch mark on one end of the stock on the point of the tail center.

Advance the tail quill while holding the stock and matching up the other punch mark to the center drill.

Turn the spindle by hand several revs. to start the center drill inthe stock while advancing the tail quill to follow.

When the point of the drill is buried in the stock, start the lathe and hold the stock and advance the tail quill until the center hole is deep enough.

Stop, back out tail quill, reverse stock and repeat.

Put center in headstock and turn.

http://bbs.homeshopmachinist.net//smile.gif

yf
08-09-2004, 11:51 PM
Or you can use a centering machine.

Which is what I do. http://bbs.homeshopmachinist.net//wink.gif

zl1byz
08-10-2004, 01:31 AM
<font face="Verdana, Arial" size="2">Originally posted by yf:
Or you can use a centering machine.

Which is what I do. http://bbs.homeshopmachinist.net//wink.gif</font>

Centering machine? pictures

Ryobiguy
08-10-2004, 01:52 AM
The description of center drilling sounds a lot like the picture in the "How to Run a Lathe" South Bend book, where the guy has this huge billet he's just holdin' on to with his hands while drilling. I saw that and chalked it up to people just being crazy back then (i.e. compare safety standards,) but perhaps that's demonstrated because it's the way that works when you don't have something better.
Snowman, let us all know how it goes when you decide on what to do.

John Stevenson
08-10-2004, 03:56 AM
Fix he damn lathe and you won't need a mandrel
Buy a 4Mt to 3Mt reducer.

If you don't do the simple things first you'll end upchasing your tail 'till you are either too old to chase it or dead.

Not much point owing a machine that's unuseable. Like coming out each morning to go to work and finding you have two slow punctures and your tyres are flat every morning.

You can get by without a steady by making one.
Get a piece of hardwood about 3" square and 1" thick and bore a hole in 1 1/4"
Turn a short piece of material up in the chuck to the same size.
Push the wood onto the stub and with a piece of angle iron in the toolpost screw the wood to the angle.

DON'T move the cross slide, wind down the bed, put your piece in the chuck and wind back to support it, run slow, plenty of oil and it works a treat.

If you setup on a stub close to the chuck it will remain parallel.
This is the quickest way to set a steady up, even a proper one.


------------------
John S.
Nottingham, England

RobDee
08-10-2004, 07:57 AM
The problem with running the stock between two centers is it must have no bow or warp because this would be reflected in the cut.
Are you saying you don't have an independ. chuck?
I agree with some of the other, get your lathe useful then do the job right.

snowman
08-10-2004, 02:38 PM
I entirely plan on ordering the MT converter, getting a steady rest, etc.

I need this part machined today. It's for my potters wheel, and I need to get work out so I can make money so I can buy a steady rest http://bbs.homeshopmachinist.net//smile.gif

For today, I'm using a friends lathe while I wait for my order to arrive.

I'll try the drilling between centers though. Unfortunately, I need to get a 5C collet block because my headstock chuck doesn't go small enough to grip a center drill. Again, I need to buy a proper chuck. All in good time. For now I'll fight myself. I'm only 24, I've got many years to get this lathe up and running properly. Or at least rebuilt so I can buy a bigger and better toy machine http://bbs.homeshopmachinist.net//smile.gif

THanks for your help,

-Jacob