Machine Gloat

[Paul39]

For several years I have been assembling parts to build a BIG bowl lathe - 36 to 48 inch swing.

I have a 2 3/8 inch shaft and two ball bearing pillow blocks, cast iron 3 V sheave, new Baldor 3 HP 3 phase motor, and a pile of steel. All acquired for 25 cents a pound from my local scrap yard. I also have a tailstock from a big metal lathe with #2 Morse taper.

I have been pricing big 4 step pulleys for a countershaft to slow down the motor 1725 rpm to about 50 rpm or less at the slowest speed. I suffered from sticker shock, and thought I could make them as I have a 10 inch swing metal lathe.

Today I was looking at a classified paper and found an Isuzu 5 speed pick up truck transmission for $50, called the owner, zinged 40 miles to his house and bought it.

I am so pleased I can barely stand it. Now I have to get to work, pour a slab and start welding and bolting stuff together.

I will buy a variable frequency drive to convert my 240 volt single phase to three phase, and have variable speed to boot.

[Pat]

Paul, you forgot a minor thing - the pics:U

[Paul39]

I KNEW that was coming!

Go to your nearest tranny shop and ask to see a greasy 5 speed on the floor.

Patience, patience.

[Tim the Timber Turner]

Hi Paul

I suspect that 3 HP will not be enough by the time you allow for power loss through a gearbox.

My uneducated guess is that you will need at least double that.

I once saw a prototype lathe that had a gearbox with a 3 Hp variable speed motor.
It would not run at more than 1500 rpm without load, before it cut out on overload.
This was due power loss through the gearbox.

Without doubt not enough power would be avaliable to turn 4ft (1200mm), even geared right down slow.

Step pullys, belt drive and electronic variable speed is the way go.

Sorry to be a Kill Joy.

I'll follow your journey with interest.

Cheers

Tim:)

[Big Shed]

Maybe you should have bought the engine with the gearbox:D:rolleyes:

[hughie]

I shall follow this with interest as have thought about doing the same. :2tsup:

[TTIT]

The lathe my old man made for himself used a gearbox for the speeds - bloody noisy mongrel thing :C:~. Needless to say when he went to the big shed in the sky, I offered the lathe to the rest of the family. BIL used it for a while and is holding on to it in case one of the grandkids wants it but he went out and bought an MC900 to use instead. Making your own stepped pulleys would be a much better idea!!:; (IMHO)

[dr4g0nfly]

I've seen enough greasy lumps sat on workshop floors in my time - just flogged an old MG BGT!

However WiP pics as the job progresses might be a damn fine idea. I find the idea of a vehicle transmission as a speed changer quite unusual.:;

Given any thought to leaving the V8 on the other end and rigging up a foot throttle? - Nahh, bad idea!:no::no:

[Paul39]

my inspiration is 's bowl lathe:


<hr style="color:#F0E9D0; background-color:#F0E9D0" size="1"> Nah! 's got a bowl lathe to play with now. We have dubbed it the "VB72" cos it cost him 3 slabs of <acronym title="vBulletin">VB</acronym>. Its got a truck gear box and bloody enormouse face plates. Don't ask me any other technical questions. Its blue is all I know.
__________________
anne-maria.

And Rude Osolnik's bowl lathe, photo here:

http://rudeosolnik.com/?q=studio (http://rudeosolnik.com/sites/default/themes/rude_osolnik/images/studio_01.jpg)

Note the transmission shift lever to the right of the big stepped pulley.

Turning the input shaft by hand on the Isuzu transmission in any gear takes just a bit more effort than turning a radio dial, so I don't think there will be much friction loss.

Some of the newer transmissions use auto transmission fluid rather than 90 weight gear lube. I am sure that makes a difference.

I have a 1967 one ton truck. In winter when it is below freezing it takes both hands to get the tranny in gear because of the 90 weight oil.

Not a new idea, 1937 Popular Mechanics:

Popular Science - Google Books (http://books.google.com/books?id=bSgDAAAAMBAJ&pg=PA90&lpg=PA90&dq=lathes+using+auto+transmission&source=bl&ots=Uf3gfcb7LD&sig=S69YAMEL21GNAPnZZBTFmQvjcQ8&hl=en&sa=X&ei=TYwlT7f5Bqng0QGe3ei1CA&sqi=2&ved=0CIYBEOgBMAU#v=onepage&q=lathes%20using%20auto%20transmission&f=false)

[Grumpy John]

my inspiration is 's bowl lathe:


<HR style="BACKGROUND-COLOR: #f0e9d0; COLOR: #f0e9d0" SIZE=1>Nah! 's got a bowl lathe to play with now. We have dubbed it the "VB72" cos it cost him 3 slabs of <ACRONYM title=vBulletin>VB</ACRONYM>. Its got a truck gear box and bloody enormouse face plates. Don't ask me any other technical questions. Its blue is all I know.

.............................................


has since converted the "VB72" into a spindle lathe, just like nature abhors a vacuum, abhors bowl turning :D :stirthepot:. I know he changed the motor over and put a new start switch on it, not sure if he kept the gearbox or not :shrug:.

[Harry72]

A gearbox from a motor bike would suck less HP.