Polishing metal and heat treating

I don't see what the problem is really with doing it with a file. It just needs a simple exercise to learn the skill. Start with a 3" cube of mild steel and have a surface and angle plates handy plus some blue although I use raddle, a mix of very find lead oxide and oil. The only other tool needed at this stage is a 10" 2nd cut file.

Work one side flat, then one square to that and so on to make up a perfect cube. After a few weeks of 8 hours a day using plasters to cover blisters things will begin to be looking good. At that point measure it and pick a size to work to. The cube will probably be around 1.8" per side so pick 1.7". Now work it down to that size retaining a perfect cube. Then use radius gauges to add a rad to all edges - when the guage is on it no light let through allowed. At this point may as well make it into something - a dice. So with a height gauge lightly scribe out boxes to mark the position of the dots exactly at some drill size. Then take it to a drilling machine and pull the drill as it's going in so that it breaks the scribed lines on all sides indicating positioning to 0.001" or better. While there drill and tap a corner so that it can be mounted on a base. End result

I've tried to keep the scribed lines visible. It's as good as the surface and angle plate. I aught to throw it away really as it most definitely isn't the one I made. They go away for chroming and get mixed up when they come back and this one has more dots errors than mine. The rads are worse too in places as is one of the dimensions.

Then make a base. This time it can be loosely sized with a hacksaw and cold chisel that also has to be made but it has to be filed to exact sizes this time and bought true on the plates.

Next is a bit of fitting. A square within a square. Corners drilled at 1/8" to make it easier. Inner square exactly 1" outer 1 3/4 with chamfered edges. All 1/2" thick. The aim is a light force fit even with the inner square rotated with an even pressure as it's pushed through from either side.

Then a bit of press tool fitting. Make an oblong template say 1 3/4 by 1 with a 1/4 concave rad on on corner and a convex one on the adjacent corner using a shadowgraph at a rather high maginfication. The aim is to size to a thou or so. Then fit this to an aperture in block of steel 1 1/2 thick.

Band saw out the rough shape of each side of a pair of engineers pliers and file to shape, drill the pivot area and send away for case hardening. Bit of light relief at one point - make a 3 draw toolmakers cabinet out of 16 swg sheet. Cut, File to split scribed lines, bending, brazing and riveting etc. They get thrown onto the floor very firmly to check the brazing.

Can I still do it. Not to the same extent. If I had several years of work like this I probably could but strength and stamina would be a problem.

John

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Thank you all. I guess I will be learning how to hand scrape. I have just fly cut and occasionally used a surface grinder. The Whitworth book is all about scraping and the Gelbart videos show more about it. I will make the vise first and get an estimate of how much is taken off in this operation.

Special Note. Thank you David for the Gelbart videos!!! I like his explanations and did learn some interesting things. I cringed when he used a caliper to scrape the steel. The Laser Indicator, I WANT, WANT, WANT!!! I have ordered the LED's and am trying to figure out how it stays on the chuck. It would have saved me a days work over the last couple of months building work fixtures. Many, many times I need to drill back from the edge and in the center. I would only have to make one measurement instead of two. In particular, I have to take some stamped Chinese steel plates and enlarge the hole from 1-11/32" to 2.120". I can use this to locate center quickly for setup. I'm going to put this at the top of the list to do for the drill press first and mill second.

Thanks everyone for the ideas. Charles

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Charles,

Recommended reading on Dan Gelbert's laser 'centre finder'

**LINK**

MichaelG.