Making a face plate, what steel to use?

[verbotenwhisky]

Discs

Dia.

Dia. Tolerance

Yield Strength

Hardness

Max. Hardness After Heat Treatment

Specifications Met

1/2" Lg.

Each

1" Lg.

Each

3" Lg.

Each

6" Lg.

Each

2"

-0.003" to 0"

Not Rated

Rockwell B70 (Medium)

Rockwell C60

ASTM A108

7786T12

$4.55

7786T14

$6.84

7786T16

$16.13

7786T18

$29.28

2 1/2"

-0.003" to 0"

Not Rated

Rockwell B70 (Medium)

Not Rated

__

7786T211

5.42

7786T212

8.06

7786T213

21.07

7786T214

41.27

3"

-0.004" to 0"

Not Rated

Rockwell B70 (Medium)

Rockwell C60

ASTM A108

7786T32

8.18

7786T34

13.06

7786T36

35.09

7786T38

69.30

3 1/2"

-0.004" to 0"

Not Rated

Rockwell B70 (Medium)

Not Rated

__

7786T221

10.77

7786T222

16.00

7786T223

41.84

7786T224

81.95

4"

-0.004" to 0"

Not Rated

Rockwell B70 (Medium)

Rockwell C60

ASTM A108

7786T52

14.34

7786T54

21.31

7786T56

55.70

7786T58

109.10

4 1/2"

-0.005" to 0"

Not Rated

Rockwell B70 (Medium)

Not Rated

__

7786T231

18.75

7786T232

27.87

7786T233

72.84

7786T234

142.68

5"

-0.005" to 0"

Not Rated

Rockwell B70 (Medium)

Rockwell C60

ASTM A108

7786T62

21.05

7786T64

33.05

7786T66

94.90

7786T68

186.63

5 1/2"

-0.005" to 0"

Not Rated

Rockwell B70 (Medium)

Not Rated

__

7786T241

27.41

7786T242

40.73

7786T243

106.47

7786T244

208.57

6"

-0.005" to 0"

Not Rated

Rockwell B70 (Medium)

Rockwell C60

ASTM A108

7786T72

25.77

7786T74

46.86

7786T86

128.87

7786T78

234.30

6 1/2"

0" to 0.125"

Not Rated

Rockwell B80 (Medium)

Not Rated

__

7786T251

26.30

7786T252

47.34

7786T253

131.49

______

__

7"

0" to 0.156"

Not Rated

Rockwell B80 (Medium)

Not Rated

__

7786T261

31.19

7786T262

56.15

7786T263

155.97

______

__

8"

0" to 0.156"

Not Rated

Rockwell B80 (Medium)

Not Rated

__

7786T271

36.44

7786T272

65.58

7786T273

182.18

______

__

9"

0" to 0.188"

Not Rated

Rockwell B80 (Medium)

Not Rated

__

7786T281

43.74

7786T282

78.72

7786T283

218.68

______

__

10"

0" to 0.25"

Not Rated

Rockwell B80 (Medium)

Not Rated

__

7786T291

49

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[n9viw]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

And only twice what I paid for two of them! Glory, I'm in the wrong business.

 

[verbotenwhisky]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

And only twice what I paid for two of them! Glory, I'm in the wrong business.

Yeah, I do not buy metal from McMaster but they are a very good sounding board for what is available and if I didn't have a saw and needed a large disk it would be a good resource because their disk are at least cut square with the edges and the faces.

 

[WobblyHand]

And to think, all this nonsense would have been obviated if I had just bought a blank iron backplate and learned to thread come hell or high water...

There's no good reason, you can't learn to single point thread (on a functional lathe with lead screw). I've seen a lot of people be totally intimidated by this, who do a lot harder things. It's not that hard. It takes some seat time, to develop muscle memory, but if you can stand and chew gum at the same time, you can single point thread. If I could learn it, anyone can.

Get yourself some 1/2" PVC pipe, you know, the cheap stuff. Chuck it up and try cutting a fine thread. Say, like 28 or 32 TPI. This will slow down the process and give you time to react. Practice the timing of getting the lead screw to engage correctly. That and when to disengage the lead screw. Start out at the lowest speed and work at it until you get things right. Then as you get more comfortable, try a new piece, but use a coarser thread (at the same slow spindle RPM). Try 10 or 13 TPI. You will have to practice getting the disengagement consistent in the middle of the thread gutter. That cutter is moving a lot faster, so you need to develop the correct reflex. Work on that a bit. Once you become more comfortable, try some aluminum, like 6061, and try that. Before you know it, you'll be fairly proficient and you will wonder why on earth you were avoiding learning this skill. If you run into problems - make a post on it and people will help you.