Thread: The Journey for a Master Square

Originally Posted by Brobdingnagian

Fire?

For the Aluminium.

double srinkage allowance was in my head from earlier in the thread. I see now thats when we were talking about machineable wax to Aluminium.

Shame the shaper didnt get a run though.

Stuart

Originally Posted by Stustoys

For the Aluminium.

double srinkage allowance was in my head from earlier in the thread. I see now thats when we were talking about machineable wax to Aluminium.

Shame the shaper didnt get a run though.

Stuart

Don't worry the old girl will get a good workout and maybe a bit of a tune up when it comes time to true up the casting. And of course there will have to be a video of that (shoooosh, clink-clack, click click click, shwoooosh, clink-clack, click click click.....)

The old girl does not get to come out and play much but every time she does I wonder why I don't use her more often.

-Josh







.

How are you going to do the internals? A separate core box? Lost foam insert?

Michael

Originally Posted by Michael G

How are you going to do the internals? A separate core box? Lost foam insert?

Michael

It is a split pattern so it will be green sand, and will not be a need for cores.

I'll repost the 3d pdf of pattern model. hang on.... ok done. that box splits in two where the drafts meet.

Originally Posted by Neil317

That is looking great, gotta love CNC for patternmaking! To me the webs look chunky enough to not cause problems. Christian, I once left a little jelutong dust on the table... instant rust when the coolant hit it on the next job. Used Renshape ever since.
Neil

Hello Neil,

I haven't noticed rust but I did have some staining when I got lazy and didn't vacuum up the jelutong chips. I'm pretty cautious now about cleaning it up. I haven't used Renshape, it looks to do a good job and I guess you don't have to worry about problems like grain or imperfections that timber brings. After watching a couple of videos where Renshape is being used it looks like it creates a fine dust. I've not sure I want that floating around the workshop (I don't have an enclosed mill). At least with timber the waste either goes in the fire or into the garden and I have the tools to work that properly.

Christian

Sorry for the delay in replying Ewan, I am away a present.

One example of a square as I described is the Webber True Square, accurate to 0.2 um in flatness & //, 1 sec <, good enough for hack work Not made in India or China.

There's currently one for sale here if you're interested Webber Gage True Square TS44 w Y 210 1 | eBay

All of the cubes I've seen were simply hollow, however if you have access to a copy of Moore's FMA book the box straight edge they replace the camel back with (as the CB was not considered stable enough), is essentially as described.

Sorry I have no idea as to the local foundries' wisdom in this area. I do recall Craig Donges, who we purchased our camel backs from, had a hell of a time finding a suitable foundry in the US who could do precision casting of low residual stress castings in the appropriate grade of cast iron.

Michael I was riding past your place yesterday and almost snuck in to see your latest gear handiwork. Regarding stresses, an interesting exercise I've not yet tried is to grind a block of 4140 accurately, heat it then plunge into cold water. Repeat and repeat. I understand that given enough cycles (and patience) the cube can be morphed into a good approximation of a sphere.

Pete

Originally Posted by Pete F

All of the cubes I've seen were simply hollow, however if you have access to a copy of Moore's FMA book the box straight edge they replace the camel back with (as the CB was not considered stable enough), is essentially as described.

Pete

Moore's Straight edge is kind of what you described, it is used on its edge at 45 to form 90 degree V ways. It has a small bearing faces and would not be suitable for a master square, master straight edge sure but not a master square, its squareness is irrelevant as it could be almost any angle Moore just chose that 90 Vee profile because the master straight edge could then be made to be self proving. It is designed to be rigid along its edge not its face under load and the exterior is not the whole story I think internally you will find it will have some filleted orthogonal cross bracing otherwise I don't think it would not be rigid enough.

The true square is too thin to properly transfer its geometry for my purpose. It would however be exceptionally good for gauging orthogonal and parallel relationships when laid flat against its 5th face.

I finished off the sony indicator stand this afternoon.

The stand is nice and solid. but damn this gauge is sensitive, It came with a data logger. I will have to plug that in and give you guys a demo

Some more of Christian's brilliant handy work.

IMG_5712.jpg

Wow this thing is going to be a whopper.

Just look at it all 8 pieces all aligned as near to perfect as you could ever want.

I've sent off an email to the foundry to get an idea on lead times and to see if it is possible to be there when they are getting poured. If you where interested in getting a "series one" poured for yourself, let me know via a PM this week some time.

-Josh

Sure looks the business to me, but what would I know? hehe
Are the halves just pinned together?

Would be great if they let you watch(an video of course )

Stuart

Originally Posted by Stustoys

Sure looks the business to me, but what would I know? hehe
Are the halves just pinned together?

Would be great if they let you watch(an video of course )

Stuart

In that photo they are low strength glue with paper between the two halves. Pins to come so I'm told.

It would be very cool if they also let me video the pour.

-J

Originally Posted by Brobdingnagian

Some more of Christian's brilliant handy work.

IMG_5712.jpg

Josh.

Go ahead and knock those up in bulk. I've pre-sold 250 of those to a Coptic Christian Church in Brunswick.

Ray and I journeyed to Melbourne today to visit Christian.
Before we set off Christian sent me this teaser.

IMG_5720.jpg

The photo does not really do it justice, it is absolutely superb, and the size is perfect, just what I had in my mind.

We took along our Renishaw QC-10 BallBar (tenth micron probe) to put on the Tormach Vertical CNC Mill, the same machine used to mill he above pattern. (If I figure out a way to export the report i'll post it here later or maybe it would be better in the CNC section) As only its second outing the ballbar is still one of those instruments that amaze me in its simplicity and usefulness One of the reasons the pattern turned out so nice is that according to the ballbar the machine has a circularity of 36 microns, and with a couple of adjustment it could be 1/3 that, I'm very impressed. The other and really the main reason the pattern turned out so nice is Christians care and attention to detail through out the entire process. Thank you again Christian for all your hard work, hopefully the iron version does it justice (he even installed tapered alignment pins ).

I talked to the foundry today to confirm the quote and their requirements, also they are happy enough to let me watch the pour. The foundry said it will take them a day to do the moulding and they will call me so that I can come over the next day to watch the pour and if they have cooled down enough take them home. Then it will be into the heat treatment oven for a day or two.

I will be ordering 6 to be moulded and cast. Three will be used for the scraped masters the rest will be surface ground to match the masters.

Wow didnt that come up pretty!
Whats the process for filling(?) and painting?

Tenth micron..... thats not a lot lol. Worked out a way to check your lathe spindle yet?

Did the foundry have much to say about the sort of cast iron they are going to use? or are you leaving that in their expert hands?

Stuart