Making a face plate, what steel to use?

[n9viw]

First off, I know I'm doing this backwards. I know that the 'right' way to make a faceplate would be to clamp it in a chuck, face it, flip it, turn a shoulder, clamp the shoulder, turn the rim, bore it, and thread it. At least, that's the way I've seen it done in a number of videos and posts.

However...

I don't have a chuck, nor have I money for one. This is a hobby, and gets the hind tit for funding. Also, my 10R has the prewar 1-7/8"-8 spindle thread, which is difficult to impossible to find chucks and plates for. And as I'm greener than grass squitters, I don't know how to turn threads yet.

I found (and purchased) nuts from McMaster in that thread, bored them for the thread register, and faced them. They fit great, and my facing is true to within a thousandth, which is a) all I can measure with a Fowler dial, and b) the best I can do for now.

My plan is to buy a steel blank, weld it to the nut, then turn and face it true. Once done, I plan to borrow the use of a neighbor's mill to cut radial slots in it for clamps, dog tails, etc. I can also make basic jaws to hold work as a quasi-chuck until I've saved enough to get a real one.

My question is, for the work done on a face plate, as well as for ease of machining, what kind of steel should I look for to make the plate? I was planning to use HRS from a local metal yard, but I've read a few threads about how HRS is gummy and doesn't face cleanly, and the mill scale is abusive to HSS bits. I have access to CRS there as well, and they can order other stuff if I know what I want. But I don't, so was hoping you might.

Thanks for any suggestions.

 

[Ulma Doctor]

ideally, face plates should be made from cast iron.
if you could braze or otherwise weld the nut you have fabricated to whatever material you can get,
then machine the faceplate in situ, that's gonna be good enough for non nasa contract work

 

[rabler]

I'm no expert so I won't pretend to have the best answer. I think cast iron is preferred to steel for absorbing vibrations? But my gut feeling is that given it is being welded, HRS or CRS are your options. Lots of other alloys can be welded but it gets more complicated, and given limited funding I think your better off going with one of these two and saving your money, just about any other steel is going to be more expensive. You can take the mill scale off HRS with a flap disk on an angle grinder, which will help your tooling. It doesn't machine the nicest but it is machinable.

Not sure about the forces on welded nut face plate. Wouldn't want it to fail on an off-center load. I'll revise that, 1-7/8" nut is a fairly good size. How were you going to weld? MIG, TIG, stick, gas .... that might make some difference in what alloys could work.

 

[Nesse1]

I have a Taiwan made 6" 3 jaw you can have for shipping cost. It came on my 1994 Tida made 12x36 machine. Not much more to say, but it's got to be better than making your own chuck...

Pretty sure it would fit into a USPS flat rate box of some size, so that should be $25 or so.

 

[markba633csi]

For threaded spindles traditionally cast iron is used because it is less likely to seize up or gall, which can make the plate very hard to remove

 

[den-den]

My face-plate is made of hot rolled steel welded to a heavy nut similar to what you propose to do. After welding, I heated it up and cooled it slowly for stress relief and when cool, machined it flat on the lathe. I do have a chuck, so don't use the face-plate often but it has met my needs so far. It should work for you (use never-sieze on the threads).

 

[Jake M]

First off, I know I'm doing this backwards. I know that the 'right' way to make a faceplate would be to clamp it in a chuck, face it, flip it, turn a shoulder, clamp the shoulder, turn the rim, bore it, and thread it. At least, that's the way I've seen it done in a number of videos and posts.

However...

I don't have a chuck, nor have I money for one. This is a hobby, and gets the hind tit for funding. Also, my 10R has the prewar 1-7/8"-8 spindle thread, which is difficult to impossible to find chucks and plates for. And as I'm greener than grass squitters, I don't know how to turn threads yet.

I found (and purchased) nuts from McMaster in that thread, bored them for the thread register, and faced them. They fit great, and my facing is true to within a thousandth, which is a) all I can measure with a Fowler dial, and b) the best I can do for now.

My plan is to buy a steel blank, weld it to the nut, then turn and face it true. Once done, I plan to borrow the use of a neighbor's mill to cut radial slots in it for clamps, dog tails, etc. I can also make basic jaws to hold work as a quasi-chuck until I've saved enough to get a real one.

My question is, for the work done on a face plate, as well as for ease of machining, what kind of steel should I look for to make the plate? I was planning to use HRS from a local metal yard, but I've read a few threads about how HRS is gummy and doesn't face cleanly, and the mill scale is abusive to HSS bits. I have access to CRS there as well, and they can order other stuff if I know what I want. But I don't, so was hoping you might.

Thanks for any suggestions.

Cast iron and cast steel are used typically for a couple of reasons. You're welding a nut onto a flat round. Both of those reasons just flew out the window. Whatever you can get your hands on will be great.

Mild steel (cold or hot rolled) will give you fits with surface finish. You're not building a church here (at least not yet), and the huge diameter will give you fits trying to get a good finish on anything from the beginning to the end, just due to the diameter change. If it doesn't come out good, move the carriage back, cover the ways, and dust off the high spots with a sander. So long as you get it flat on an average, ugly won't bother anything.

I'd say you just want whatever they're selling as mild steel. Cold rolled if they're cutting a circle from flat stock, as that's a LOT of material to peel mill scale off of. Aside from being hard on cutters, it's not good on the bed ways either. If you end up with a slab of bar stock, that smaller amount of mill scale is a lot more manageable, I'd save a buck.

I'd also get it thicker than you need, probably at least a half inch. Maybe three quarters depending on how big you're making it. Welding a nut in there is gonna make everything crooked. You're going to have to take off more than you'd expect. it may well (but not necessarily) be enough that you need to take a skim off of the back side too, just to keep it balanced. And you'll still want some pretty tangible metal there if you're boing to bolt things to it.

Or maybe you get lucky and something factory made shows up out of the blue.....

 

[savarin]

I used HRS for a back plate for my 4 jaw, welded a large chunk of bar on the back, bored and threaded for the spindle, screwed back on to the spindle and trued up front and back and dia.
I dont think you will have any problems welding the nut on and truing up afterwards.
use an angle grinder with a cut off disk to remove the corners if your plate is square as the interrupted cuts really jar the system.

 

[machPete99]

Face plates are typically not used very often. You would be better served by saving up for a decent chuck.

 

[francist]

Given the choice between hot or cold rolled I think I would go with the hot. For one; I find it turns a little more predictably than cold rolled which can have hard zones right next to soft spots and two; cold rolled can have a real tendency to warp if you remove more metal from one side than the other. Might make for a nightmare trying to true the face.

If you’re worried about the mill scale, an hour or so in muriatic acid takes care of that nicely. Just do it outside and not near any tools or machines you care about. Supposedly vinegar works too, just slower.