Source for ground mild steel plates

[Patrick Chase]

In my previous thread somebody asked about a source for ground mild steel or cast iron plates. I answered that I've gone through a friend's machine shop, but somebody else brought up Speedy Metals and Online Metals.

It turns out that Online Metals in particular sells Blanchard-ground 1018 (mild steel) plates in appropriate thicknesses (https://www.onlinemetals.com/merchant.cfm?id=1160&step=2&top_cat=197).

With shipping they end up more expensive than the Veritas plates per unit area, but I think the Online Metals ones may be better with fine-grit (1 micron and below) diamond compound, for two reasons:

Roughness. The Veritas plates are milled rather than ground, and the surface texture looks like the aftermath of a fly cutter, though I doubt that's what they used. Veritas claims that the texture helps the plates hold diamond particles, and I think that's true for coarse grits, but they mostly seem to scratch tools when used with fine-grit paste. Back when I was using the Veritas plates exclusively I ended up lapping the ones that I paired with finer-grit pastes on sandpaper to "soften" the milling marks. Blanchard-ground plates should be smooth enough for fine-grit paste out of the box.

Flatness. The Veritas plates have a 4-mil flatness spec, and I've seen examples that are warped by a few mils lengthwise. That translates to a couple tenths of a mil across the width of a 2" chisel or plane blade, which is a nonissue for coarse particle sizes because the next grit down will be aggressive enough to quickly fix that sort of mismatch. It becomes a problem with very fine pastes because they take forever to remove any geometry mismatch from the next plate up. Fine-grit lapping plates have to be dead flat or at least identically warped, and blanchard-ground plates should also do well in this respect. As I noted in my previous post, MDF also has enough "give" to mitigate small flatness mismatches, so the other option is to just use that for your finest grits.

I ordered a 3/8" thick 8x8 plate for kicks to see how they work. I'll probably cut it into a pair of 4x8s.

Online Metals is the retail arm of Thyssen-Krupp, so they're extremely reputable.

[Gerry Grzadzinski]

McMaster-Carr has a 3/8" 4"x12" precision ground plate for about $37.

They don't specify a flatness tolerance, but the thickness tolerance is ±.001"

[Nicholas Lingg]

https://na.dmecompany.com/Catalog/CatalogListing.aspx?CatalogId=DME&CatalogDetailId=1031

[Tom Bussey]

There is a difference between flat and parallel. It can be bowed like a banana and still be the same thickness. However precision ground plate should be flat enough for most woodworkers.

[george wilson]

Enco and MSC Co. sell precision ground low carbon steel. Looks just like precision ground tool steel as far as looks go. A nice,pretty finely ground surface. Much nicer than Blanchard ground. Oh,my friends at Victor Machinery Exchange in Brooklyn.New York probably sell it cheaper.

To tell the truth,by the time a guy beats the dovetails together on a plane,he possibly will have wasted the nice surface,and will have to file and sand the whole thing to get the surface finished again. I have found cold rolled mild steel sheet to be quite useful. And cheaper.

[Mark Fisher]

Precision ground plate is probably annealed prior to final grind......should be pretty darn flat.

[george wilson]

It is as accurate as any other tool steel. But,it may not be as true after having the dovetails peened together.

[Paul Saffold]

Lee Valley has them but only size is about like a sharpening stone.

[Patrick Chase]

Lee Valley has them but only size is about like a sharpening stone.

See my original post - the Veritas plates are milled rather than ground, and that has both advantages and drawbacks depending on the use (LV and Veritas are one and the same)

[Paul Saffold]

Wow, I certainly was asleep at the wheel on that one.

[lowell holmes]

I have to assume you fellows are talking about flat plates for lapping and sharpening.:)

I am completely happy with wet sandpaper on my granite plate that I bought from Woodcraft. It is indeed flat.
I only mention as an alternative to flat.

[Patrick Chase]

I have to assume you fellows are talking about flat plates for lapping and sharpening.:)

I am completely happy with wet sandpaper on my granite plate that I bought from Woodcraft. It is indeed flat.
I only mention as an alternative to flat.

Sandpaper is only an alternative to very coarse (large-particle-size) diamond pastes. I have 45, 15, 3, 1, and 0.25 pastes in common use. 15 is #1000, so that's the finest one that overlaps sandpaper. In my experience the economics in terms of sandpaper/paste expended per grinding session are comparable (and both lose badly to waterstones in that respect), but diamonds are a lot faster and do better with really hard steels.

[Tony Zaffuto]

The LV Spring 2016 catalog arrived today and the Veritas honing plates are pictured. Definitely have the look of a fly cutter, with a flatness tolerance of .005" over the entire 3" X 8" plate. On page 148 of their 2015-2016 LV has pictured their Veritas lapping plate, which is ground to a tolerance of .001" over the entire 4" X 12" surface. The lapping plate also has grease grooves milled into the surface.

For my purposes, I use a granite plate, but not with loose diamond or Sc grit: IF I use it, a quick spray of 3M #77 adhesive, with a sheet of 3M Sc paper affixed is it. I don't get too anal on flattening or lapping (but then again, I have a full machine & tool making shop in my plant, and on occasion, I have had one of my tool makers grind plane soles flat and/or square).

[John K Jordan]

I have ordered several times from Online Metals and found them to be fair and prompt and the products as advertised. I bought steel, aluminum, and brass.

JKJ

[lowell holmes]

I will have a set of planer knives sharpened and Back on the planer in 20-30 minutes. It suits my needs. I often make rocking chairs and tables, so micro flat is not necessary. All of my grandchildren are rocked in chairs I made.:) My chairs are 40% machine made and the rest chisles, shaves, and knives.

I'm glad Tony spoke up and let me know I'm not the only one using granite.

It also is a good reference surface for visual check flatness of a surface. It's large enough to accommodate checking large surfaces for flatness.

[Tony Zaffuto]

I will have a set of planer knives sharpened and Back on the planer in 20-30 minutes. It suits my needs. I often make rocking chairs and tables, so micro flat is not necessary. All of my grandchildren are rocked in chairs I made.:) My chairs are 40% machine made and the rest chisles, shaves, and knives.

I'm glad Tony spoke up and let me know I'm not the only one using granite.

It also is a good reference surface for visual check flatness of a surface. It's large enough to accommodate checking large surfaces for flatness.

Be careful following anything I say Lowell: if my chairs rock, it's not because I made them that way!

[Patrick Chase]

Enco and MSC Co. sell precision ground low carbon steel. Looks just like precision ground tool steel as far as looks go. A nice,pretty finely ground surface. Much nicer than Blanchard ground. Oh,my friends at Victor Machinery Exchange in Brooklyn.New York probably sell it cheaper.

For a lapping plate a finely ground surface isn't automatically better. For finer-grit compounds I sometimes condition my plates by lapping them on 60-grit SiC.

[george wilson]

Oh,I read the 1st post just after I got up. I thought he wanted to make dovetailed planes from it!!:)

I have had a bad night,taking my wife to the emergency room,and getting home at 5:00 AM. Long story short,she took a new sleeping pill her Dr. prescribed. Passed out in the bathroom and crashed face first into the bathtub. Luckily she broke nothing.

[Tony Zaffuto]

Oh,I read the 1st post just after I got up. I thought he wanted to make dovetailed planes from it!!:)

I have had a bad night,taking my wife to the emergency room,and getting home at 5:00 AM. Long story short,she took a new sleeping pill her Dr. prescribed. Passed out in the bathroom and crashed face first into the bathtub. Luckily she broke nothing.

What was she prescribed George? My dooc prescribed (IIRC) Lunesta for me. Took it once, wife threw the rest out, after she had to put up with a night of me babbling about slaying dragons and other stuff!

[Patrick Chase]

Oh,I read the 1st post just after I got up. I thought he wanted to make dovetailed planes from it!!:)

I have had a bad night,taking my wife to the emergency room,and getting home at 5:00 AM. Long story short,she took a new sleeping pill her Dr. prescribed. Passed out in the bathroom and crashed face first into the bathtub. Luckily she broke nothing.

Eek, sorry to hear that! I hope everyone is doing OK now.

[george wilson]

I don't remember,but she isn't going to take any more sleeping pills!

[lowell holmes]

Well, suddenly this string is not very important. I'm sorry George, we will have you in our prayers.