Where to support a grinder table when scraping?

Hi all I have been scraping a grinder table and didn't initially give much thought to how to support it while scraping, I just scraped it on an old wooden work bench. I moved it to a friends place and put it on his surface table and the alignment value I am getting from the King way type tool I made has changed. The ways consist of a flat way and an inverted V.

Question is do I put it on a surface plate which supports it everywhere evenly to check for alignment? Or should I be supporting it at the Bessel points or something?

Many thanks.



Incidentally my method of scraping for alignment was to scrape both sides of the V flat first, then scrape the flat part flat. After this is done there will be misalignment in the sense of the top of the 'new V' being out of alignment with the flat part. Then my plan was to make the alignment tool and rescrape the flat part until the imaginary top line where the sides of the V meet were in line with the flat.
Image of it being out of alignment (the angle of 120 degrees is random, obviously it will be something other than this):

After this is done I hope to match the ways of the saddle with the table using the table as the master. No doubt there will be more considerations once I get to that stage.

You need to set it on 3 points. I have to first find the center of gravity in both directions. Most machine builders have shown you the front to back because they put the rack there. But an easy way to figure it out is to let a 2 x 4 on the floor or a 2" pipe and set the table top side down and find the balance point. Then depending on the long way if the table is the same looking then you would set it at 30% from the ends.


I made a set of steel horses or steel stands and cut 2 x 2x 3" soft wood blocks and set 2 at 30% from the end and in from the edge 30% on one side and the another 2 x 2 x 3" under the rack surface or where the center balance point is. No need to get it level as long as it is stable. You can lay 2 x 4's bext to the sides to block it doesn't slide on the blocks when you scrape it. You could also set it on a heavy duty table or cast iron surface plate as long as it is heavy duty. Another thing you need to do if you haven't already done it.


Before I dismantle the machine and it is still under power I take off the Mag Chuck and grind the top of table with coolant to break through the work hardened iron that gets rusty and hard. If you already have it apart, then scrape the rust off and then hand or power scrape the top of table. You will see how hard that surface is because as you scrape it, it will dull your carbide blade and once your through it will get softer. Another thing is to ring the table once you have it sitting on the 3 points by hitting it with a dead blow hammer.


If the table has been sitting cock eyed for a while, set it on the 3 points over night. For the fun of it check it with your home made kingway and mark it on table. Make marks where the KW stops and then let it set there for 8 hours and check it again. Many times if the design of table is weird or lopsided I will move the single block side to side finding the balance point. If it is not in the center moving it over the balance point it will change the direction of the bubble. It is fun seeing how flexible a table is if you have never seen it.

It sounds as if you have already discovered that. LOL On bigger machines I will usually set the blocks under the ways. You should also do this on the saddle now before scraping it. On a grinder and the majority of machine ways you scrape the long part first. Also before you match fit the table to the saddle be sure you have tested the saddle ways to make sure they are not twisted as that flimsy table will twist to the solid saddle if it is twisted. Rebuilding a grinder and most machines is like building a house. Solid and kevel foundations and as you work up keep things square, level and solid. I have a picture of a Monarch Lathe . The one end I used what I call the "Bridge" when the single point can't be set there because it's hollow, Plus the 3 point steel horse I made. Be sure to come back and tell us your feedback. Rich

Side-note: I like how you made the V-way end of that king way. Looks simple but effective.

M.B. Naegle said:

Side-note: I like how you made the V-way end of that king way. Looks simple but effective.

Click to expand...

Didn't you take pictures of mine at the class you tool at Steve Watkins? Everyone else did.

You Wrote:

Incidentally my method of scraping for alignment was to scrape both sides of the V flat first, then scrape the flat part flat. After this is done there will be misalignment in the sense of the top of the 'new V' being out of alignment with the flat part. Then my plan was to make the alignment tool and rescrape the flat part until the imaginary top line where the sides of the V meet were in line with the flat.
Image of it being out of alignment (the angle of 120 degrees is random, obviously it will be something other than this):

After this is done I hope to match the ways of the saddle with the table using the table as the master. No doubt there will be more considerations once I get to that stage.[/QUOTE]

My Answer:

No one cares if the V ways are a 45 degrees or 60 degree as you are "rebuilding" the machine not building it. All you care about is making the invisible datum lines parallel to each other. Trying to measure the thickness of the V way is irrelevant because you are scraping the flat parallel to the V. Then when you are done you will grind the table top to make the table parallel to the ways at that single point.

Richard King said:

Didn't you take pictures of mine at the class you tool at Steve Watkins? Everyone else did.

Click to expand...

Yes, but yours rests on a "half-pipe" piece, correct? His is a pair of bars on arms. Just thought it was an interesting approach.

To be honest it was a bit of a stuff up on my part, I copied it from Wes Johnson's youtube video. My version was not made accurately enough and the 4 drill bushes cause it to rock. It needs to be remade but gives a reasonable reading in its current state if you prevent the rocking.

Thanks for the reply Rich when Marcus and I get further into getting it going I'll put up some progress shots.