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View Full Version : New Bull Center What A Waste of Metal!



cybor462
05-06-2007, 11:18 PM
Well as we all saw in a previous post from CCWKEN he made a 4" live bull nose center. I needed one too and have started. I only had a piece of mild steel oblong roughly 11" dia. I need to cut it down to 5" I filled 2 barrels today with chips. Makes me wonder why!

Here it is so far.

PS dont look at the ugly weld. I welded the flange on and will bore it for the bearing.
http://mywebpages.comcast.net/cybor462/bull.jpg
http://mywebpages.comcast.net/cybor462/bull1.jpg

Yep, the top is what I started with and am now left with the bottom.
This really pushed the limits of my Grizzly lathe. The work I started with was from the scrap yard and it had a 1/2 cutout along the outside dia. Every time it came around it hammered the insert and the tool post/cross slide.

Amazingly the insert did not chip but the tool post was moving to the beat. I will not be so ready to do another like this again. I do not think it did my slide or post any good!

Any suggestions for a place to buy a bearing. Bruce gave me two the other day. One is too small and the other too large. Sorry Bruce I will give them back or use them on another project.

speedy
05-06-2007, 11:52 PM
Any suggestions for a place to buy a bearing. .

Headstock bearing?;)

Been there before, ugh! It feels nasty when hammering the lathe like that.
For future reference you could have machined a ring off that lump and avoided the cut out and hammering.

cybor462
05-07-2007, 12:00 AM
Ken.. no I need a bearing for the bull center. No thanks to a spindle bearing. So far it all seems fine.

When you say machined a ring off..do you mean plunge cut?
If not what other way might I have chosen?

speedy
05-07-2007, 12:32 AM
If it was an old bit of scrap that I wanted to utilise, as you did, I would have also welded 'outrigger' supports ( to support the outer ring) then machined in from the face. A facing cut back a tad from the finish size using a 'v' ground HSS tool. First cut maybe 1" wide and getting smaller as I machined deeper.
My first option would have been to gas cut to a diameter closer to the finished size. then cleaned up with the grinder before machining. However if you do not have O/A etc then that option is out.

torker
05-07-2007, 12:41 AM
I agree with cutting it smaller with a torch or you also could have welded the hole up to make the cut smoother. I do this a lot but usually heat the welded area up to cherry red (then let cool slowly) to get rid of the hard spot.
Russ

mark61
05-07-2007, 07:38 AM
>>>Any suggestions for a place to buy a bearing. Bruce gave me two the other day. One is too small and the other too large. Sorry Bruce I will give them back or use them on another project.[/QUOTE]<<<<<


Timkin wheel bearing set off of 1 of your "donor" parts storage machine in the yard? Put a couple of straight bearings behind it. Have to think more where to find those on the storage unit.....

mark61

jimmstruk
05-07-2007, 10:08 AM
For a taper bearing (timken type} go to auto supply and buy front wheel bearing for rear wheel drive car. Like a small Ford or chevy. They can carry 1000 pounds for many miles at speeds your lathe will never see. JIM

malbenbut
05-07-2007, 11:19 AM
Is there any reason you did not trepan the 5" dia out of the disc.If you felt the metal was to wide you could have reversed it in the chuck.
MBB

cybor462
05-07-2007, 01:51 PM
I agree with cutting it smaller with a torch or you also could have welded the hole up to make the cut smoother. I do this a lot but usually heat the welded area up to cherry red (then let cool slowly) to get rid of the hard spot.
Russ

That is if you have a torch. Momma don't let me play with fire!:o
So I did it the only way I could. I did it my way.....Melody!

cybor462
05-07-2007, 01:56 PM
Is there any reason you did not trepan the 5" dia out of the disc.If you felt the metal was to wide you could have reversed it in the chuck.
MBB
First I did not know what that meant. Googled it to find it is a form of boring. Not sure how that would have helped make the 11" disc 5" I had to bore the flange only for the bearing. I welded the flange on since my stock was not wide enough to mount the bearing.
If trepan has another meaning I do not know it nor do I know of the process. Sorry all Greek to me:confused:

brucepts
05-07-2007, 02:53 PM
Hey Klem, ah . . . why didn't you ask me if I had any 5-6" steel while you were at my place since we had no luck at the scrapyard? :)

Coulda beat that peice of steel senseless in my Big Ole American Iron Hendy, would not have even felt that interupted cut . . .

cybor462
05-07-2007, 03:03 PM
Actually I have a 6" piece but it was only 1/2" thick and I needed 3/4". But you already gave me bearings! Which I have to order them anyhow. How come you did not know they would not work? I relied on you and now you let me down:(

Ok hope your mad but... I still need to email the cad drawing so you can fix it so I can submit it. You can make it up to me by doing that.

I am a real *ss huh?:rolleyes:

But really I do need to get bearings. The flange I had to use had a larger bore than the one I had in your shop. The large bearing is way too large that I would have to bore into the drilled holes and the small one falls in so I am off to the new catalogs I just got.. Read the whopppiiieee post.

Joel
05-07-2007, 03:11 PM
Trepanning is taking a plunge cut on the face of the stock using a single point tool. The result leaves a groove or kerf like a holesaw.

Try searching for trepan and trepanning on this site. There should be no shortage of good information.

cybor462
05-07-2007, 03:19 PM
I had thought of plunge cutting it with a single point tool but did not know it was called trepan. I will search here and gather info on it. I also thought of welding the cutout but was afraid it would harden it.

Was well worth the beating to know I will not do it that way again.

Thanks for the info.

kc5ezc
05-07-2007, 07:20 PM
Trepanning is brain surgery. At least getting to the brain through the skull. And I have just about as much luck doing either. MEW #124 has an article that may help. I'm going to try it tomorrow. I need to learn this technique.
John Burchett
in Byng OK

torker
05-07-2007, 08:40 PM
That is if you have a torch. Momma don't let me play with fire!:o
So I did it the only way I could. I did it my way.....Melody!
Another thing you can do is pour the filler metal in as hot and quick as possible. This will heat it up enough. Just let it cool slow...dump wood ashes on it.
Russ

S_J_H
05-08-2007, 12:20 AM
I have trepanned on my 9x20 Grizzly. I had a need for some cast iron and a old 7x faceplate was used for the project. I just ground a HSS parting blade to work. It's basically face parting and it can save a lot of time if the part can be trepanned. It took just a few minutes to cut this free from the faceplate and leave me with the material I needed for the project.
http://i109.photobucket.com/albums/n48/S_J_H/7xcompoundconversion.jpg
Steve

cybor462
05-08-2007, 08:24 AM
That is cool. I will remember (I hope) to try it next time.

Heah Steve your lathe is way too clean!

Elninio
05-08-2007, 04:29 PM
what lathe is that?