Cold Rolled Steel Suppliers...

[skhawley]

I made mine with 1x1 Cold Rolled steel using penrose instructions.
- Buy a bunch of C clamps, put them on and don't take more than one off until your done drilling.
- File both side flats, it will extend the range of tapers you can make. (yes I cut my first side to deep)
- Email Mr. Swearingen he knows more about this than all of us combined.
- Don't worry about the thousands of an inch perfection , get in there and file it flat with a random pattern
- You don't need shoulder bolts but they look Cool.
- Don't use Blind Holes Penrose has them and it looks nice, but you don't need them, ask any machinist they will tell you the same I drilled mineout and taped them later.
- A triangle file is a 60 deg angle.
- Find a friend to help file, it will take a while.

[joehudock]

Check the tolerances. PDF]Carbon Steel and Alloy Bars - Ryerson
https://www.ryerson.com › s2693referencetolerancescarbonalloybarsfinal
NOTE — Straightness tolerances do not apply to hot rolled alloy steel bars if any ... After Cold. Cold. Inches or less .55% incl. Finishing. Finishing. 11⁄2 or under.

I found that Ryerson site pretty inscrutable for finding the tolerances on steel bar. McMaster-Carr https://www.mcmaster.com/standard-steel-sheets gives a tolerance of 6 thousandths on cold rolled 1018 and 2 thousandths on 12l14 for 3/4 inch square bar. But that's for all bars not for over the length of a given bar. Then there is allowable bend and twist in a bar. I haven't found any supplier yet able to give an answer on that.

[canerodscom]

It’s been a long time since I made forms but I seem to remember that the lion’s share of the filing flat was because each corner of the bar stock is slightly rounded. Perhaps 1/64” radius? That matters when you’re only cutting a few thousandths off the corners to cut the groove.


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[JimmyB11]

I have made a number of planing forms from 1018, the tolerances are very good on this material and will yield an excellent result. The tolerances are not an issue. If you are hand planing a groove how can you expect close tolerances on that aspect? As I mentioned in a earlier post, the drilling of the holes for the dowel pin is the most critical aspect of getting the left and right side aligned. If you buy a 10' or 12' bar and mark the sides then cut it in half your "half bars" will VERY close in tolerance as they came from the same "master" bar. Then do your drilling on the same side of bar as it was made as in top, bottom, left, right orientation. Mark the master bar with a Sharpie before you cut it. Again, the drilling for the pins require careful execution and set up, this will give you a fighting chance to have decent homemade forms. If after your forms are pinned and the left right is wonky no amount of draw filing will get you where you need to be. You should not have to spend time draw filling if you get it pinned correctly.

[joehudock]

It’s been a long time since I made forms but I seem to remember that the lion’s share of the filing flat was because each corner of the bar stock is slightly rounded. Perhaps 1/64” radius? That matters when you’re only cutting a few thousandths off the corners to cut the groove.


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Here's a photo showing the depth between the clamped bars I worked on.


Assuming my geometry is OK it looks like the bar corners have around 1/32" radius so there was a lot of filing to be done on the tip end of the form to have a 0.020" tip depth 60 degree V-groove at the first station. It was about 90% or more of the total filing needed on the forms to get those rounded corners down to size.

[joehudock]

When it comes to flat filing the planing form I found this bit of arcane technology from the century before last a help in taking down the steel surface and keeping it flat:


The file holder also reduces wear and tear on hands and gloves. Combined with a sharp Vixen file it worked like a charm for me first time I tried it. I do have a couple of 14 inch bastard cut hand files but the above combination worked so well I stayed with the Vixen file.
Here is the 19th century description of the devise by Col. Sam Nicholson, a civil war veteran who was running the business back then (it didn't hurt that his dad owned the company).

[LeeO]

I think I walked about 2000 miles draw filing my forms. About three feet at a time