Converting my Engine Lathe to an 8-Station Turret Lathe!

[widgitmaster]

Last week while surfing through eBay, I stumbled across a used 8-station turret like the ones on a Hardinge Chucker! Immidiately I placed a bid and slapped a massive MAX bid on top of that to ensure I would win this little gem! And I did!

It arrived today, and when I opend the box it looked perfect! Upon a more serious examination, I saw that the previous owner had taken a 2" diameter pnumatic sanding disk and pollished all the external surfaces to make it nice and shiny!

Well, that proceduer had distroyed all the precision surfaces, so I disassembed the turret, and proceeded to remachine all the parts to restore it's precision! The octagonal turret fit nicely in my 3-jaw chuck, and with a dial indicator through the center hole I was able to dial in the precision surface on the inside! Then I took a .005" face cut ant now it looks perfect! The micrometer shows a .0003" out of parallel condition.

The overall quality is fantastic, as every part is chrome plated and ground and heat treated! The underside of the cast iron turret and it's mating part is also Chrome plated and ground! This turret has a pneumatic valve to relax the turret for manual indexing in either direction!

All I need to get is a few new rubber o-rings!

The base plate is also cast iron, chrome plated on the top side and heavily sanded by the previous owner, resulting in a tapered surface of .006" So I put it in my mill, and took a skim cut across the butchered surface!

Total cost with shipping was: $145.67

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[widgitmaster]

Next I removed the compound from my lathe's cross slide, to see how this turret would fit! The cross slide has a round t-slot groove, with a steel boss protruding in the center. The is proving to make this a little complicated! Fortunately, the turret is best located in the center of the cross slide, and that is far enough away from the boss to eliminate any conflict with the internal air ports!

I looked at it closly for several minutes, thinking how an adapter plate can be made to fit between the cross slide and the base of the turret!

The other option is to replace the exsisting base plate with one that is customized to fit on top of my lathe's cross slide! A nice cast iron plate would do the job just fine!

Tonight I'll play around with my CAD program to see what size plate to order!

Does anyone know what the distance from the spindle center to the top of the turret is on a hardinge chucker? I would like to make mine standard, so I can use all the pre-existing tooling instead of having to make my own!

to be continued . . . . .

[LUCKY13]

Nice score on the turret, it funny what people will do to things. Sanding a surface like that just so it looks good for there pics. Oh well, atleast it was fixable, and the price was right to.

Should make things a little quicker for you when you go making those batches of little goodies I have seen you post about.


Is that turret made to switch with air, or does the air just lock it in place & you turn it manually after unlocking?

I cant help you with the measurments you need, but your right, a little pre planing on the setup will make things a bit easier & cheaper if it works out to whats already out there.


Just wandering, what kinda lathe is your? Its not CNC is it?


Jess

[widgitmaster]

No, the AIR just locks it down, a really slick design too!
As for the measurement, I remembered way back when I ran a Hardinge Chucker, we used to place 3/8" tool bits right on the top of the turret, and they were centered perfectly! And by flipping the tool bits upside down, you can measure the distance from the tip as it gets ground back, and add little shims to correct the center line! (that's an old memory too! 1975 !!)

I have entered most of my data into the CAD, and it looks like a 2 1/2 x 6 x 12 piece of cast iron is what I need! I can't wait to use it, as I have so many little parts to make out of 303-SS and bronze!

The only problem is when I made my carrage stop, it has 5 positions, NOT 8 like the turret! It looks like a replacement part for the stop is inorder too!

My lathe is a 13x40 geared head Gap Bed lathe, made by Birmingham!

Widgit

[keithorr]

I tracked that on ebay. Really good price. I've only seen a couple of them before.
I also wondered how to mount one. I figured I'd just mill off the compound boss. If the unit is mounted mid cross slide, how will you set tools for turning? Looks like you'd only be set up for face and drill operations.

[widgitmaster]

Actually it's a pain to mount, as the exsisting compound has a post to mount on! I will be making a plate which straddles the top of the carrage, and fits over the boss. Then I'll add a few SHCS to fasten it to the carrage.

Most turret lathes use long solid tool holders to turn long diameters, but after 5 or 6 inches they are not very accurate and the part requires a support center!

The turret will be an accessory, and with a few screws is ready to go!

I have been wanting a turret lathe, as I've been running off lots of 50 pcs of little parts, and the Quick change tools I use have not been very efficient!

It seemed to be more economical to make a turret lathe than to buy one!
I hope I don't eat my words!!

Widgit

[widgitmaster]

This morning I called Speedy Metals 1-888-744-4140 and ordered one piece of cast iron for the adapter base plate!

A 12 1/4 x 6 1/4 x 2 1/4 piece of cast iron cost me $85.98 including UPS shipping!

That's still cheaper than buying a used Turrel Lathe!

Widgit

[jackson]

This morning I called Speedy Metals 1-888-744-4140 and ordered one piece of cast iron for the adapter base plate!

A 12 1/4 x 6 1/4 x 2 1/4 piece of cast iron cost me $85.98 including UPS shipping!

That's still cheaper than buying a used Turrel Lathe!

Widgit

your are going to have to show us when you get it all going

[Mcgyver]

nice find Eric, way to go.

[widgitmaster]

Today I did a little reverse engineering!

After finding all the pins that fit the holes in the base plate, I set the part on an angle plate on my surface plate. Then I used my little height gage to calculate all the distances and center locations of all the holes!

But first I made a full scale sketch on some graph paper and added the dimensions as they were calculated!

All I need now is that big slab of cast iron!

Widgit

[jackson]

Today I did a little reverse engineering!

After finding all the pins that fit the holes in the base plate, I set the part on an angle plate on my surface plate. Then I used my little height gage to calculate all the distances and center locations of all the holes!

But first I made a full scale sketch on some graph paper and added the dimensions as they were calculated!

All I need now is that big slab of cast iron!

Widgit

Cant wait to see it in action

[bill south]

Eric;
That's probably one of the cleanest lathes I've ever seen!!! I think this thread is going to be fun to follow. Keep up the good work.
Bill from Spartanburg.

[LUCKY13]

It took me awail to understand how the turret worked ( by looking at your pics of the pieces). But I think I understand now. The locking part is bolted down to the base, inside of it is a piston, the piston has a arbor that goes threw & bolts to the turret(top). So when air pressure hits it, the piston raises the turret top, which lets the eight(I believe it was eight) regesters seperate so it can be rotated.


That looks like a pretty good design. It has a lot of regester surface to keep it in possition. So it should be very accurate (repetable) when rotated.


One thing I am not understanding is your use of the pins ( when making the gragh for the base plate). Are these pins in holes that are used to attach to the base plate that your making? I understand how your using the pins to find the center of the holes. But, what are the holes for?



Also, someone else meantioned about the type turning that could be done with this setup. It is pretty much like any other turret lathe. But after thinking about it I got to wandering if there is things that you would be limited with this type setup. ( remember I am not with expeirance of lathes). Anyway this got me wandering about having it mounted as a rear tool post. I guess one thing that is not known for me is how the cutters/tools attach to the post. So I dont understand the possition of the tool. So what kinda tool holder attaches to a turret of this type?



Jess

[widgitmaster]

LOL Bill!
That is a picture of my lathe when it was brand spanking new! It didn't even have power connected, fresh off the forklift!

As for the turret's function, there is a large diameter piston inside which when air pressure is applied, pulls down on the top turret and locks it into position on the eight alignment rails.

There are many types of tool holders for this turret, ranging from turning to facing to boring and angle turning! Then there is a holder with a 5/8 bore which can hold Geometric Die Heads and large boring bars! Also the basic drill chucks!

[BobWarfield]

Same tooling fits gang tool plates for Hardinge CNC's as well as Omniturns. There is another thread where we're discussing building such a plate for mini-lathes. I like that style of tooling. It also looks like it wouldn't be that hard to make your own holders, especially for the Widgitmaster!

Eric, from your photos above, I am inferring that you used your surface plate and height gage to measure coordinates for all the features on the base plate and then transferred that to a drawing on graph paper. Did you literally measure X and Y with the plate rotated 90 degrees?

FWIW, a list of those coordinates would make doing a drawing in most any CAD program super easy. I happen to prefer Rhino, but there are many available, and it seems like it would save you some time.

Best,

BW

[widgitmaster]

Thanks Bob!
Yes, I clamped the plate to angle plate so I could lay it on it's side and measure the other direction!

Not all the dimensions were direct transfers to the new plate, as the origonal plate was goofy and had the turret sitting on an angle????

So I calculated all the bolt circles and rotated it so one flat edge of the octagon was perpendicular to the spindle! Then I had to relocate all the air porting and re-design the valve assemble! Challenging, but fun


Widgit

[widgitmaster]

Made a little progress today!
I found 4 out of 5 O-Rings in ACE Hardware!

Now the search is on for the big 4 3/4" OD O-Ring for the main piston, it has a thickness of .145" (but it is very worn and disfigured)

I have been told that the "Make-Your-Own" O-Rings don't hold up well within a sliding mechanism, so I will search for a direct replacement!

Yesterday I re machined the small bearing surfaces that contact the thrust bearings when the turret is lifted and rotated, those surfaces had slight wear grooves in them. About .005" deep.

The CAD file is finished, and waiting for the slab of cast iron!

Widgit

[lerman]

Mcmaster (www.mcmaster.com) will have a replacement o-ring for you. .145 doesn't seem to be a standard size, but a nominal 1/8 o-ring measures .139 and should be close enough. Just pick a material that is suitable for the lubricant you are using and it should be fine.

Ken

[Runner4404spd]

the original size was .125. seals always swell when coated in lubricant.

[LUCKY13]

Widget, you might make a trip to your local Transmision repair guy to find a good Oring that will work. You could even machine the piston to work with the lip type seals they use in a lot of the tranny pistons. It might hold up a lot better than a normal Oring. It would be something to fall back on if you cant find what you need anyway.


Jess