Turning down a long shaft on a short lathe

[Superbowl]

I have used roller box tools on my turret lathes and they do a good job once you get the tool ground properly and get them adjusted to the desired diameter. The catch is that they are meant to be turret mounted and are normally used for relatively short work limited by the turret travel. For this job, you need to mount a big box tool with a 7/8" or larger hole through the shank to your top slide, probably with a custom adapter of some sort. The box tool has to be centered and parallel with the lathe spindle, of course.

I have box tools, but none with that big a hole in the shank. You will need at least a 1.25" shank and you will need to be sure the cutting diameter capacity will do your job.

This one might work, but the 1.5" shank is not drilled all the way through. Hole size not given, but it looks pretty big. Selling in a few hours, low bid at present.

https://www.ebay.com/itm/354884102347?hash=item52a0bda8cb:gRkAAOSwnbxknzdY&amdata=enc:AQAIAAAA0FxkWEdtEpGF0/CfCROOzKbQTpsYOzYWj4AZNN5EQglTXR5M+raubLtDINKSSHJgcA5TZ1GqjwEQW8eloOPq894K3k0z3x09hGBDw/I2zodC9UDO2EGeh38SPN0KdSRvzbsUAAraSPg++v+sJQ5EivANnCElfPILtk4BmG+Rw/kpDPUmdnJI02aLfDt2ouwaC8RG+oyfc937S+Lbv6qYPS/ScZEl3zpWvYaTpLlXfEyActT+ys/w9UMQtk99WLYtcJtDhvqPap/njlsbwBN7hYU=|tkp:Bk9SR-6MtJKmYg

You might find a shop that does custom centerless grinding and save a lot of aggravation.

Or get wheels with 7/8" bores.

Larry

Thanks for the link Larry. I just bought that box tool on ebay. It seemed a better use of my time to modify it than to start from scratch and make something like the nifty custom tools others have posted photos of.
Dave

 

[L Vanice]

Thanks for the link Larry. I just bought that box tool on ebay. It seemed a better use of my time to modify it than to start from scratch and make something like the nifty custom tools others have posted photos of.
Dave

Now you need a 3/4" tool bit. You can use a brazed carbide bit with a square end. I mostly turned 12L14 with HSS tools. A plain end grind that follows the factory shape on a new tool bit can work on brass, but I learned how to do the chip breaker grind that apparently was much used in real factories for turning steel. Here are a couple pictures of one of my Hardinge-size roller box tools with the bit in place to give you an idea of what works really well.

Larry

 

[Nmbmxer]

I cut the shank off my box tool and welded on some 3/4” sq cold rolled to fit in my toolpost.

 

[Superbowl]

Now you need a 3/4" tool bit. You can use a brazed carbide bit with a square end. I mostly turned 12L14 with HSS tools. A plain end grind that follows the factory shape on a new tool bit can work on brass, but I learned how to do the chip breaker grind that apparently was much used in real factories for turning steel. Here are a couple pictures of one of my Hardinge-size roller box tools with the bit in place to give you an idea of what works really well.

Larry

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Thanks. I will have to look around in my stuff. I may have a 3/4" tool bit somewhere.

 

[Superbowl]

I cut the shank off my box tool and welded on some 3/4” sq cold rolled to fit in my toolpost.

I am thinking maybe I can adapt the box tool to an Aloris tool holder. Then I can easily adjust the height.

 

[jims]

I am thinking maybe I can adapt the box tool to an Aloris tool holder. Then I can easily adjust the height.

Box tools are mostly used in turret lathes. And they are put on centerline by inserting them in the turret On centerline.There are two ways to use them. One is to set the rollers on the stock dia. And the other is set the rollers on dia you are cutting. Best way for you is to set them on od of material you are cutting. It is tricky to grind a box tool because you are grinding the end of a tool. And it looks different than a standart tool grind. Micro100 sells tools made for box tools. But they can be pricy. But looking at their catolog can give you an idea of how to grind them. I can grind them in just a few minutes on my bench grinder by hand but that is because I have been using them for 70 years. In fact I made a video showing how they worked on the Hobby Machine forum.
BUT BEFORE YOU TRY TO LEARN A NEW TOOL I WOULD SEE IF YOU CAN FIND A COMPANY NAMED. LONG BAR
GRINDING. IN LOS ANGELES AREA.
They grind 12 foot bars all day long .

I found Longbar Grindings phone # 562 921-1983
they are in Santa Fe Springs Ca.

 

[rons]

When I bar feed on my DSM-59, I use a piece of DOM tubing to contain the rotating bar and lash the DOM to one or two heavy V-head pipe stands depending on length. The worst the rotating bar can do is slide around the inside of the DOM, stopping the positive feedback that turns it into a people killer, machine smasher, and floor gouger.

As long as you are getting the right people...
What about drilling out the center and then mounting the hanging end into a live center held securely.

 

[michiganbuck]

We had a video posted a time ago that had a long stick-out accident,
Even a 1/2" hard whack might break an arm or kill someone.
Guess one could park the hi lo at the out end with a steady..but the parts mid-section could whip.
I have fudged up tall fixtures to brace tall grinding parts.
For gun barrels, I used the right tool rake angle to assure the least amount of pressure and used a steady.

 

[MrWhoopee]

No need to turn the whole thing to size. Determine the locations of the bearings and turn those segements individually. Concentricity is not important. Undercut the sections between slightly.

 

[michiganbuck]

I think 24" out on the clausing with the aid of the steady to take .020 or so should be a piece of cake on a 32" clausing....pretty quick easy job

 

[Superbowl]

Box tools are mostly used in turret lathes. And they are put on centerline by inserting them in the turret On centerline.There are two ways to use them. One is to set the rollers on the stock dia. And the other is set the rollers on dia you are cutting. Best way for you is to set them on od of material you are cutting. It is tricky to grind a box tool because you are grinding the end of a tool. And it looks different than a standart tool grind. Micro100 sells tools made for box tools. But they can be pricy. But looking at their catolog can give you an idea of how to grind them. I can grind them in just a few minutes on my bench grinder by hand but that is because I have been using them for 70 years. In fact I made a video showing how they worked on the Hobby Machine forum.
BUT BEFORE YOU TRY TO LEARN A NEW TOOL I WOULD SEE IF YOU CAN FIND A COMPANY NAMED. LONG BAR
GRINDING. IN LOS ANGELES AREA.
They grind 12 foot bars all day long .

I found Longbar Grindings phone # 562 921-1983
they are in Santa Fe Springs Ca.

Hi Jim's. Do you have a link to your video?

 

[jims]

I have a 7/8" (22.15 mm) diameter rod of mild steel 48" long that I need to turn down to 21.75 mm.

I have two lathes, a 10ee with about 18"-20" of working length to the tail stock and a Clausing 6300 with about 30"-32" of working length to the tail stock. I have steady rests for both but no traveling rests.

I am wrestling with the best way to approach this job as I have never worked with something this long.

The 10ee is clearly the most rigid lathe but has the smaller working length. If I use it I could start by facing one end and center drilling it using a helper steadying the other end with a piece of pipe to keep to it from whipping around. Then extend it to a live center in the tail stock and turn down a section. I could then flip it around and do the other end the same way. This leaves the middle section which would have to be done using a steady rest instead of the tail stock.

If I go with the Clausing I could do it in only two sections but with no traveling rest I might have more deflection to deal with and this lathe is much less rigid.

Anybody have experienced in working with long shafts have a recommendation?

Hi Jim's. Do you have a link to your video?

Email me your email and I will email the vid to you.
[email protected]

 

[Superbowl]

Email me your email and I will email the vid to you.
[email protected]

Will do, thanks.