initial machining of a Denis Foster Featherlight 12 x 30 x 4" box square

With a ton of help from my friend Bryan and his Haas VF-5SS vertical machining center, I got a great start on machining my Featherlight square. I am excited about how it is turning out and I am really looking forward to working on scraping it in. I will bring it to the Richard King scraping class in Olympia, Washington next week. Here is my little article:

http://nwnative.us/Grant/shop articles/featherlight

metalmagpie

I updated my project blog with pictures of the sides after milling. You can see them by clicking on the link in the previous post or here:

Metalmagpie,

It looks like you are doing a first-class machining job on this square. Nice that you have access to a large enough VMC to be able o do all four sides and one set of minor edges in one setup. Assuming (a good assumption I think) that the VMC ways are in good condition, you should end up with very good perpendicularity and and parallelness right off the bat. So, you should have to do minimal planar corrections of the major faces when you are scraping. The way you approached the initial setup with the pucks and jack was excellent. It would be nice If I could say that the raw casting would/should be plumb and true and perpendicular as cast. Wishful thinking of course as this is a casting first of all and secondly, to get the thickened edges of the faces while allowing for the web of the faces to be thinner requires the use of loose pieces in the pattern and they simply will not locate perfectly parallel to the main body of the casting. So they introduce some mild irregularity of the minor edges---a fair price to pay for saving nearly half the weight that the casting would otherwise be.

It will be interesting to follow your scraping progress as well. You will be going straight from flat scraping to adjusting plane angles in all three axes. Good for you.

And thanks for posting about your machine work. Lots and lots of folks have posted here about simple straight edge machining and scraping. But, I don't think anyone has posted about machining and scraping a cast square.

Denis

I will be teaching him to scrape it and check for squareness before we scrape it and during. Hopefully he will be able to remove all the machining marks during the class to square .0001 or less per foot. 30 to 40 points per inch. I will show him and the other students how to ring vibration stress relieve it too. We will blue it, check it for square, ring it and then re-check it before scraping. It will move a little I am sure. That will be a case study... The class starts Wednesday in Olympia Washington. The host has a granite square we will use to square it too. The class is full with 12 students. I have another class in Vermont in September we have room and some in CA in October and November. If it is safe. We will be wearing masks an sterilizing everything daily.

Thanks, Rich. I can't wait for class to start!

I finished the part of the project blog linked to above. It now shows the completed part.

metalmagpie

Sure looks like a very nice user friendly design and casting!

Scraping a project like this will be much more challenging than a straight edge. Good on the OP for taking it on. Will be following with interest.

Lucky7

Woops, it's Featherweight not Featherlight. Sorry, Denis! New link:

http://nwnative.us/Grant/shop articles/featherweight

Day 1 of class went just great! Excellent bunch of guys and a wonderful teacher!

metalmagpie

I got a chance to see Grant's Featherweight in person and the machining looks really nice and consistent. This will be an excellent tool when we are done with the scraping class.

Dennis, do you have a website with your available castings?


Matt Rulla

metalmagpie said:

With a ton of help from my friend Bryan and his Haas VF-5SS vertical machining center, I got a great start on machining my Featherlight square. I am excited about how it is turning out and I am really looking forward to working on scraping it in. I will bring it to the Richard King scraping class in Olympia, Washington next week. Here is my little article:

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metalmagpie

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If I may ask : what is this Featherlight square and what is used for ? In the pictures looks very nice. What is it made from ? Stainless steel I guess.

Truebor, it's cast iron, not stainless. Denis does his own patternmaking, molding, and casting. As to what it's for, it's a large square and typically would be used for machine alignment where a smaller square is inadequate. Because of its size, it could also double as a short precision straightedge as a scraping reference.

Edit: I fixed the embedded images.Originally they did not show up perhaps due to there being several hours between writing the post and actually posting it.

sfriedberg,

Thanks for stepping in for me.I spent a long day at the foundry molding, setting up the furnace, melting and pouring and then doing the inevitable cleanup.I couldn't have said it better.

Matt, thanks for the kind words. I agree that Grant did a superb job of machining the square.

The short answer is no I do not have a website for SE sales. If I were a businessman, I would. But, my main focus has been improving the quality and variety of straightedges that I make. Soon I will work on my eBay listings which I have not kept current—-my bad. Anyone wanting a SE can contact me via PM or email [email protected]. I much prefer email as PM’s are so limited.

I do offer PM members a 10% discount and for folks who buy one and then complete a bona-fide scraping class (for instance, Rich’s class) PM members get an additional 20% discount upon completion of the class for a total of a 30% discount to promote the craft of scraping. The 30% discount is one-time per person for one SE. The 10% is offered on multiple SE’s (This sounds like lawyer-speak, but I’ve had questions)

I currently have:
8” prisms/level/straight edges


18“ prism/level/SE/parallels

36” broad-based camelback SE’s

48” broad-based camelback SE’sPrecision Square 30x12x4 Interestingly,metalmagpie just machined his and it came out at a shade over 37 pounds. As a raw casting it is 52 pounds.

I do machine the 8, 18, and 36" straight edge. The last 36 I did a week ago was between .001 and .0015 of flat. That has been fairly typical of machined results though I quote .oo4' of flatness.. I machine them from about 20 pounds to 25.5 pounds per the buyer's preference.

Denis

Today we will start to scrape Magpie's square. It should be fun. If anyone else wants to learn how to finish scrape any of Denis's products attend one of my classes. We have one planned next month in Vermont and another on in Burbank CA in November.

sfriedberg said:

Truebor, it's cast iron, not stainless. Denis does his own patternmaking, molding, and casting. As to what it's for, it's a large square and typically would be used for machine alignment where a smaller square is inadequate. Because of its size, it could also double as a short precision straightedge as a scraping reference.

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Thank you - it looks like very nice engineering. If you have a good ( large ) grinder this you can make dead flat. It looks very solid.

Truebor, no need for a grinder. Just an adequate sized, in spec, surface plate and a few bits of metrology gear. And a little (!) elbow grease.

L7

Took a picture of Maggie's square while he scraped. Also we have 3 brands of straight edges in the class. 2 more D. Foster, Gary Martin and King-Way brand.

Also on 2nd fom right picture is Nathan scraping a 36" Foster and on far side of table is a King-Way brand that Matt was scraping I have a couple of photo's I need to download showing how we rang vibration stress relieve all of the brands hanging on a rope, striking them with a dead blow hammer and they all moved a little. Surprising the light Martin 24" (center pic) camel-back moved less then the others.

lucky7 said:

Truebor, no need for a grinder. Just an adequate sized, in spec, surface plate and a few bits of metrology gear. And a little (!) elbow grease.

L7

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Just in my opinion but I think it will be much quicker to make it dead flat with a good ( large ! ) grinder. With a good grinder you can get straight to a couple of micrometers in a meter in a couple of days. That you can not do with hand tools.

This is only in MY opinion.

TrueBor said:

Just in my opinion but I think it will be much quicker to make it dead flat with a good ( large ! ) grinder. With a good grinder you can get straight to a couple of micrometers in a meter in a couple of days. That you can not do with hand tools.

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You could well be right. But to have a shop with a big grinder work on my part for 2 days would cost way more than the part is worth. This part is designed to be machined and then scraped.

metalmagpie

Truebor, what’s your ‘big grinder’ rate per hour? How many hours do you think you’ll need for all six surfaces to be a reasonable alignment reference standard?

For my purposes, I don’t need the best a new grinder can do, just good enough for use as a tool alignment and rebuilding ref. By flat, parallel, and square, I think in imperial not metric, so within 2 tenths flat over length and 2 tenths per foot square is what I can and have done for projects that size. Oh, and 40 ppi.

And to use as a scraping ref, a grind surface won’t work anyways, it’ll just smear the dye...

Anyhoo, I think it’s a fantastic and useful project. Congrats to the OP and Denis for taking it on!

L7

Actually, the more I think about it, the thin sections this casting has, in order to reduce weight, would make grinding it a pain and a very long process. I know I couldn’t do it in two days with the Churchill I used in training. Maybe I don’t know enough about grinding?

The grinding discussion misses the point. How do you build the grinder? "with another grinder" can't be the answer all the way down. There is an "all the way down" process to make very very flat surface plates, and using those and scraping to make references that are also statistically very flat. Those are then used to make things like machine ways (which often want some tooth in them for control of stick-slip friction and for oil) - which are also scraped.

What's more, a grinder produces a ground surface (duh) - that's generally a feature, but for some of the tasks in machine building and reconditioning that scraping is used for, it's not a feature.

If you are making a precise machinist square, you very likely grind it very carefully, same with a sine bar. But ways, saddles, and the like, maybe not.