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ronsmith100
06-03-2005, 11:18 PM
I have been teaching for quite some time but some things I teach poorly I guess. It seems no matter how much I emphasize it the faceplate is simply not used enough. I have seen students struggle with aligning something in a four jaw chuck four an hour. I then show them how, in five minutes they can clamp it to a face plate and indicate it in with the ease of tapping on it with a lead hammer. I have shown them how to make a simple fixture which mounts to a face plate so they can overcome the repeatability issues of a three jaw chuck. But no matter. The faceplate is simply not a very romantic tool and it sits on the bench unused.

MMurphy
06-03-2005, 11:26 PM
Ron..I for one I'm very interested in your "simple fixture". I do use my faceplate fairly frequently. I actually kind of like it. Takes longer to set up, but I like being able to take the work off for other work, then put it back on the lathe with no accuracy penalties

Mike

precisionworks
06-03-2005, 11:33 PM
Faceplate ARE underrated. Mine is used often on jobs that lend themselves to no other form of fixturing.

One job that comes in every month or two involves setting up a part on the lathe and widening an existing groove. The back of the part has a step of .080, there are three mounting holes, and the part shape is asymetrical. I made a fixture plate that mounts on the faceplate. It takes a minute or two to indicate the part to center and the chips fly. One of the more profitable jobs in the shop, pays about 3.5 times normal shop rate. Would be far less if I had to try to coax a 4-jaw into service.

Other parts get secured to the faceplate with milling machine hold downs. Really have to watch the balance.

Carpet tape on the faceplate works wonders for thin or fragile parts that will tolerate little clamping pressure. It helps if the tailstock live center can be brought up for support.

------------------
Barry Milton

chief
06-04-2005, 12:49 AM
It's human nature, they are just too lazy to change the chuck, I see it at work too.

Evan
06-04-2005, 03:27 AM
In most cases I find it much easier and safer to jig the work to the cross slide and let the tool do the revolving. I have a selection of tool holders made from 1" square bar stock that go in the four jaw and several different jigs to hold work on the cross slide. It also makes for easy positioning. Get the height with shims and dial in the front/back if necessary. Way better than stuff flinging about on the face plate. I use the face plate if it cannot be done any other way.

JCHannum
06-04-2005, 06:27 AM
The face plate should be considered a consumable tool. Do not be afraid to drill and tap holes in it for fixturing. Eventually, it will look like a piece of Swiss cheese. At that point, discard it and get a new one.

It can also help to put a second plate of aluminum on the faceplate to do the sacrificial duty.

With a few very simple fixtures, the faceplate can do anything possible with the three or four jaw chuck. I could live without the chucks if need be, but not the faceplate.

Metal Lathe Accessories sells a faceplate casting that has T slots and tapped holes for holding. It is worth taking a look at, and modifying your faceplate to match before drilling a bunch of random holes in it.

http://www.statecollegecentral.com/metallathe/S-5879.html No affiliation, but some good accessories.

pete913
06-04-2005, 06:33 AM
If given the choice between ANY chuck and a faceplate, I'd say it was a no brainer, give me the faceplate. You can do almost anything with a faceplate and only some of it with a chuck. Chucks are handy, but not a necessity.

DBW
06-04-2005, 08:21 AM
Our English cousins have been using a wonderful combination of a faceplate and what is known as a "Potts fixture" for years. It's basicaly a
V block and U clamp which can be bolted to a faceplate with the V parallel to the lathe ways. This combination allows easy part holding and centering with a light tap of a lead hammer. Much cheaper than a chuck.

QSIMDO
06-04-2005, 09:14 AM
Could someone explain how objects are held securely on a face plate?

Old hat to most but I find all this fascinating!

Spin Doctor
06-04-2005, 12:12 PM
Sometimes with strap clamps. Sometimes with hex or socket cap screws trough holes already in the part. But a lot of times for heavier parts it is easier to mount the part of the face plate off of the lathe and then put the whole thing on the spindle mount with a hoist. Another cousin to the faceplate is the 5C collet fixture. Basically a 5C collet body with a small face plate built in
http://img.photobucket.com/albums/v19/markandannie/P1010298.jpg
Extremely useful for specialized turning fixtures.

Carl
06-04-2005, 12:23 PM
Here's an interesting faceplate setup for turning a large radius contour on a part:

http://www.nelsonslocomotive.com/Shay/Boiler/Smokebox/Faceplate.jpg

ronsmith100
06-04-2005, 01:10 PM
<font face="Verdana, Arial" size="2">Originally posted by QSIMDO:
Could someone explain how objects are held securely on a face plate?

Old hat to most but I find all this fascinating!</font>

I will try to explain here but promise to post a cad drawing of what I am talking about.

Picture a one inch thick steel plate 6" x 6"
Machine a V out of it at 45 degrees that goes all the way to the center.
Drill holes through it that match your face plate slots. Mount it to the face plate and snug the bolts.
Place a one-inch dia bar into the face plate fixture V slot with the other end supported by a center.
Use a toe clamp, mity bite or some other clamp to snug the bar into the V. Now indicate it in. When indicted dead on tighten the fixture *very* tight against the face plate and then tighten the toe clamp against the bar. You can now take the part in and out a hundred times and all machined diameters will remain concentric.

ronsmith100
06-04-2005, 01:37 PM
a simple centering fixture

http://www.jjjtrain.com/vms/face_plate_clamp.jpg

[This message has been edited by ronsmith100 (edited 06-04-2005).]

precisionworks
06-04-2005, 02:24 PM
http://www.sherline.com/images/lathfig5.gif

http://www.lathes.co.uk/labormil/img9.gif


http://iwr.ru.ac.za/~iwdf/lathe/qjr/qjr-03wheel.jpg




------------------
Barry Milton

Mark McGrath
06-04-2005, 07:54 PM
Ron,you must be teaching them badly if they struggle for hours with a four jaw (smile).I have been butchering metal for forty years and could count on one hand the number of times a faceplate was preferable to a four jaw chuck.Once the art of truing jobs in a four jaw is learned it is quicker and safer than a faceplate.No bits of packing to fly out.No extra out of balance loads to worry about.From the way you describe clamping a job to the faceplate and tapping about with a hammer to true it leads me to think you are setting up something thats already been machined on the back face in which case it can be sat back against the jaws of a four jaw and trued up very easily.By all means teach them to use a faceplate but also show them how to use a four jaw too.Another very useful setup which isn`t much used in the home shop is a three jaw chuck with soft jaws.Once you have tried that you will never leave it.
The angle plate us Brits use in the lathe is called a Keats angle bracket.It`s ok but you have to counterbalance it very carefully due to its weight.
Let the shouting commence.
regards,Mark.

Al Messer
06-04-2005, 08:27 PM
Sort of hard to turn locomotive wheels in a 4 jaw chuck, but it's a piece of cake with a faceplate, even to drilling and boring the holes for the crankpins off center.

wierdscience
06-04-2005, 10:05 PM
I have at work two steel plates(used to be blind pipe flanges)both are turned round and flat.
One has four tee slots milled in it,and the other is just a slick face.
Either one can be dropped in and indicated in a four jaw,or chucked in a three jaw with the jaws reversed.
The tee-slotted one is used as normal,the slick faced one you can tack weld your part to,them mount in the lathe.

A few bolt holes,some bolts and a stack of flat washers help for balancing.

wierdscience
06-04-2005, 10:07 PM
DDP!


[This message has been edited by wierdscience (edited 06-04-2005).]

ronsmith100
06-04-2005, 10:21 PM
<font face="Verdana, Arial" size="2">Originally posted by Mark McGrath:
Ron,you must be teaching them badly if they struggle for hours with a four jaw (smile).I have been butchering metal for forty years and could count on one hand the number of times a faceplate was preferable to a four jaw chuck.Once the art of truing jobs in a four jaw is learned it is quicker and safer than a faceplate.No bits of packing to fly out.No extra out of balance loads to worry about.From the way you describe clamping a job to the faceplate and tapping about with a hammer to true it leads me to think you are setting up something thats already been machined on the back face in which case it can be sat back against the jaws of a four jaw and trued up very easily.By all means teach them to use a faceplate but also show them how to use a four jaw too.Another very useful setup which isn`t much used in the home shop is a three jaw chuck with soft jaws.Once you have tried that you will never leave it.
The angle plate us Brits use in the lathe is called a Keats angle bracket.It`s ok but you have to counterbalance it very carefully due to its weight.
Let the shouting commence.
regards,Mark.</font>

I could be teaching four-jaws poorly too I guess. I could just be a poor teacher all the way around. However, I have not been butchering metal for 40 years so perhaps I have not seen things from your perspective. I *have* however been a tool and die machinist since 1960 so maybe that is where the confusion is http://bbs.homeshopmachinist.net//smile.gif

It is too bad you have used a faceplate less than five times in your lifetime else you would have noticed its utility. I suppose it depends on what sort of butchering you may have been doing but there *are* many irregular objects like castings that are more fit for a face plate than a 4-jaw.

As for the jig shown in my sketch, it has a pretty clear advantage over a three jaw for repeatability (meaning taking it out and putting it back several times) and it has utility for production runs where the parts all have the same diameter where they contact in the V.

I would not want to trust a four jaw to repeat as well unless I could lock down two adjacent jaws after master runout positioning so that they cannot move. In that I could use some instruction myself as I don’t know how to do it with any ease at all!

As for balance, I can see where this would be a problem for the small lathes used by hobbyists but a small amount of throw on a 14" lathe should not be a problem should it? I may be wrong about this too though! &lt;smile&gt; Maybe I have left many ruined lathes in my wake over the last 45 years and don't even know it! hahahaha

Thanks for your input, Mark

Ron

Arcane
06-04-2005, 11:12 PM
Is a heavy faceplate preferable to a lightweight one, or something in between? I am thinking of making a second faceplate suitably sized for my 9" SB and I have a chunk of round steel plate about an inch thick, maybe a little more, that I was planning to use and I thought I would put T-slots in it and several tapped holes as well.

wierdscience
06-04-2005, 11:25 PM
<font face="Verdana, Arial" size="2">Originally posted by ronsmith100:


As for the jig shown in my sketch, it has a pretty clear advantage over a three jaw for repeatability (meaning taking it out and putting it back several times) and it has utility for production runs where the parts all have the same diameter where they contact in the V.


As for balance, I can see where this would be a problem for the small lathes used by hobbyists but a small amount of throw on a 14" lathe should not be a problem should it? I may be wrong about this too though! &lt;smile&gt; Maybe I have left many ruined lathes in my wake over the last 45 years and don't even know it! hahahaha

Thanks for your input, Mark

Ron</font>

Well two points,for the three jaw to repeat just from the part being removed and replaced a marks-a-lot takes care of that.Mark the master pinion and the part where the two meet,put it back in the same spot everytime.

Second,I have had a 6,000lb gearhead start to shimmy with a 3lb offset,couldn't see it,but you could feel it.

Orrin
06-05-2005, 08:47 AM
Quote:

"Is a heavy faceplate preferable to a lightweight one, or something in between? I am thinking of making a second faceplate suitably sized for my 9" SB and I have a chunk of round steel plate about an inch thick, maybe a little more, that I was planning to use and I thought I would put T-slots in it and several tapped holes as well."

IMHO, the faceplate that Metal Lathe Accessories sells is ideal for your 9" SB. I had one on mine and couldn't get along without it. So, the first thing I did when I moved up to a bigger and better lathe was to get some more of them.

The nice thing about the MLA faceplate casting is that the center boss is large enough to accommodate a 2-1/4" X 8TPI spindle.

http://www.statecollegecentral.com/metallathe/

I recently had the job of rebuilding an antique engine "mixer" (primitive carburetor). After trying every which way to mount it in a four-jaw, I decided the only way possible to do the job was by using a face plate. Piece of cake.

Orrin

ronsmith100
06-05-2005, 09:40 AM
<font face="Verdana, Arial" size="2">Originally posted by wierdscience:
Well two points,for the three jaw to repeat just from the part being removed and replaced a marks-a-lot takes care of that.Mark the master pinion and the part where the two meet,put it back in the same spot everytime.

Second,I have had a 6,000lb gearhead start to shimmy with a 3lb offset,couldn't see it,but you could feel it.

</font>

It is not a matter of orientation of the part being machined on a three-jaw chuck. It is a matter of a three-jaw being able to put it back on the spindle centerline each time within .0005 or so. Try this: put a one-inch dia piece in your three-jaw. Machine it to something near .500 on one end. Put an indicator on it and it is going to run as true as your spindle bearings (maybe .0002 TIR). Now do your marking number on it, remove it and replace it. Put the indicator on it again and see if it is within .0002 TIR. It wont be I am sure.

As for you 6000 lb gearhead shimmy with a three pounds of offset there are many factors in play three of which may be:
1) How far off center is the three pounds? A three pound offset a short distance from spindle centerline is certainly different than the same weight placed 10 inches off centerline
2) What RPM are you turning? If you think about it you will see that the radius of the cut determines RPM and RPM determines what effect the three pounds (multiplied by the offset) has on the spindle bearings.
3) spindle bearing could have been in bad shape on your 6000 pounder and it was never evident until you offset the load.

In sum, a commercial engine lathe is not worth its weight in rocks if cannot setup and run a small offset load on a face plate. Sometimes counter balances are bolted on if it is a large load.. I would say most machinists just look at the mass, note the RPM, and counter weight as seems reasonable . However, you guys here are such sticklers for ultimate engineering exactness I am sure you would counter balance to within ounces!
Hahahahaha.
See the above picture (five or six posts up) of a small lathe turning a significant offset mass. That is very common and should not kill spindle bearings for just a part or two.

Ron

precisionworks
06-05-2005, 10:37 AM
Sounds like Thrud is back, using a different name http://bbs.homeshopmachinist.net//smile.gif

Evan
06-05-2005, 10:59 AM
I find that rpm makes all the difference when turning an offset weight in the spindle. It really depends on the resonance of the lathe. At certain rpms the lathe will do the funky chicken. Faster or slower it is no problem.

GreenWillyPeter
06-05-2005, 11:29 AM
Be sure to lock down the dog tails to the faceplate before applying power, as a safety consideration, too keep from having any unpleasant suprises. I know that tying down is something everyone does as a matter of course and shouldn't have to be restated...But...

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

wierdscience
06-05-2005, 12:41 PM
<font face="Verdana, Arial" size="2">Originally posted by ronsmith100:
It is not a matter of orientation of the part being machined on a three-jaw chuck. It is a matter of a three-jaw being able to put it back on the spindle centerline each time within .0005 or so. Try this: put a one-inch dia piece in your three-jaw. Machine it to something near .500 on one end. Put an indicator on it and it is going to run as true as your spindle bearings (maybe .0002 TIR). Now do your marking number on it, remove it and replace it. Put the indicator on it again and see if it is within .0002 TIR. It wont be I am sure.

Ron</font>

Nope,same jaw,same pinion,same wear in the scroll,they always indicate within .0002"unless the chuck happens to be packed full of crap.I'm not knocking your setup,but the common three jaw is fully cabable of being repeatable if maintained.

Offset turning is not an issue on a 6,000# gearhead with modern rolling element bearings,but on a plain bearing spindle which relies on oil film only for lubrication it can be a disaster.Babbit and bronze bearings may fair better than cast iron like in the SouthBends.
There is a big difference between a lathe that's hopping up and down and one that is shimmying for sure,but if the machine is shimmying is it also deflecting,as the speed increases so does the deflection.That deflection is more than you might think possible.

I turn out eccentric shafts for gravel shakers on a regular basis.9" od 1045 8'long with a 3" offset bearing journal on each end.
It can't be balanced and can't be spun up more than 80 rpm or the 15,000# lathe will jump,so the rough turning is done at 60 rpm and 1" doc and the finish pass is done at 18 rpm and .02" doc.Why not finish at 60 rpm? Because after checking the deflection at the tailstock it was found to be .015" http://bbs.homeshopmachinist.net//eek.gifThat's the tailstock casting,not the part.

I also about 10 years ago watched a machinist destroy a 16" Monarch with an out of balance load.He pushed the lathe up one speed change thinking it would run smoother which it did,it also instantly caused the reverse gear clutches to spall on the shaft which destroyed everything in the headstock but the cast iron cover.Shame was if he had either #1 run the lathe slower or #2 counterbalanced the load a perfectly good lathe would not have been sent to the scrap.



[This message has been edited by wierdscience (edited 06-05-2005).]

ronsmith100
06-05-2005, 03:51 PM
<font face="Verdana, Arial" size="2">Originally posted by wierdscience:
Nope,same jaw,same pinion,same wear in the scroll,they always indicate within .0002"unless the chuck happens to be packed full of crap.I'm not knocking your setup,but the common three jaw is fully cabable of being repeatable if maintained. </font>

Incredible