Building a milling machine

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mattinker:

--- Quote from: Manxmodder on March 20, 2014, 09:07:31 PM ---
Norm,an easy and cheap route to a concrete mix for filling castings is to buy a bag or 2 of ready mixed postcrete from one of the DIY outlets.

This is a dry mix for installing fence posts with cement and aggregate in correct proportions,all you have to do is mix with some water and fill your casting.

Go easy on the water content as too much weakens the concrete and takes longer to dry....OZ.

--- End quote ---

Portland cement based concrete shrinks.

Regards, Matthew

shipto:
looking pretty good so far, watching for updates :mmr:

superc:
I think you will be much better off long term with pre-washed sand from a store than with salty beach sand. Agreement the first 2 or 3 years your machine's insides won't notice it. Eventually however the salt will find metal and atmospheric moisture and the fun will begin.

I am really curious to see how the knee joint plays out as far as slop and maintaining a specific height to a few thousandths goes.

NormanV:
I have been quiet for a while, that is not because I have been idle. I have been making slow progress but I may have to cast the head casting again. I relied on my memory when boring for the main bearing and managed to make it oversize. I could make a sleeve which would probably be cheaper but take a lot more time.
Superc I'm not sure what you mean by the knee joint. If you mean the vertical slide I have already found a problem. I thought that I had adjusted it to the minimum slop but when I checked it yesterday I did find some movement in it. I think that I need to remove some of the paper shim that I have used. This is a major dismantling. I will do it when the leadscrew arrives as I will have to take it all apart to fit it.

superc:
Well yes, I meant the vertical feed. Looking at the original sketch, since I see only one screw raising the table, slop becomes a concern, especially if there is no way of firmly locking it in position. Second potential problem I see is what supports the sides of the table to keep the arrangement from rocking? Is there more than one 'angle plate' perhaps affixed to the table slides riding in grooves in the 'aluminum casting', or is there just one centrally affixed connection between the table and the main body?

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