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Surface grinder reassembly

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Tony Ray06/08/2022 15:07:34
197 forum posts
46 photos

”I watched another vid by suburban tool inc about measuring surface plates, and checked mine out this morning, and it’s out by at least 0.001 in places, possibly more. It was a £40 eBay knock off so I’m not surprised, probably fine for what I’ve been using it for - various bits of measuring and scribing, but not suitable for blueing.”

No plate is perfectly flat but if it is 1 thou out that’s a lot. Yes you can re scrape it but ideally you’d need a bigger plate as a reference. You can flatten it without but you may end up down a rabbit hole. I’d suggest holding off on this until you have that larger plate.

A 36” plate even across the diagonal is indeed a big lump. I have heard of people buying a larger plate and taking it to a stone mason to have it cut down, Like a lot of things once they get to a certain size you get more bang for your buck as they become unattractive to many buyers. You might also be able to sell on the part you don’t need.

I understand the concern re weight, I can only just lift my milling vice off the table. Maybe you can rope in some friends, neighbours, relations. If you bought a new plate with delivery they’ll get it to your door, it can sit there until the help arrives , it’s unlikely to go walkies due to its weight. According to RDG a 630mm sq plate is 90kg so a person on each corner is not too bad a lift. The methods you used to move Eagle will work. I’d help but I’m on the South Coast.

Getting surfaces flat can become an all consuming passion / addiction but all you really need to do is get to a stage where everything slides smoothly across its range and axes are sufficiently perpendicular to achieve what you need.

The tenths indicator will be a great help, A s/h M&W or Eclipse scribing stand would be a useful addition, you’ll probably need to make up an adapter to hold the indicator but it needs only to be functional.

This is turning into a great thread and I know I’ll be coming back to it when I start on my Eagle.

If anyone has seen Steve Watkins at Work on the Tube he is about ( may take some time until he posts) to re grind a Monarch 10EE be using a grinding sled. Depending on the sled complexity it could open up some new possibilities

john feeney06/08/2022 19:48:17
avatar
26 forum posts
32 photos

My Dad was a machine tool fitter for many years, he used a small block of hard felt( as used in piano hammers) for applying `blue` to the surface plate.

It was about 10mm thick, 20/25 mm wide and about 40mm long. I still have such a piece in my "scraping box" although have not done much in the last 10 years.

He worked in the Manchester/Stockport area ( mainly for Craven Machine Tools) where there was a distinct pattern of the finishing scraping, quite different from the "Halifax" pattern.

John Feeney

Steve35506/08/2022 21:16:02
259 forum posts
177 photos
Posted by Tony Ray on 06/08/2022 15:07:34:

No plate is perfectly flat but if it is 1 thou out that’s a lot. Yes you can re scrape it but ideally you’d need a bigger plate as a reference. You can flatten it without but you may end up down a rabbit hole. I’d suggest holding off on this until you have that larger plate.

A 36” plate even across the diagonal is indeed a big lump. I have heard of people buying a larger plate and taking it to a stone mason to have it cut down, Like a lot of things once they get to a certain size you get more bang for your buck as they become unattractive to many buyers. You might also be able to sell on the part you don’t need.

I understand the concern re weight, I can only just lift my milling vice off the table. Maybe you can rope in some friends, neighbours, relations. If you bought a new plate with delivery they’ll get it to your door, it can sit there until the help arrives , it’s unlikely to go walkies due to its weight. According to RDG a 630mm sq plate is 90kg so a person on each corner is not too bad a lift. The methods you used to move Eagle will work. I’d help but I’m on the South Coast.

Getting surfaces flat can become an all consuming passion / addiction but all you really need to do is get to a stage where everything slides smoothly across its range and axes are sufficiently perpendicular to achieve what you need.

The tenths indicator will be a great help, A s/h M&W or Eclipse scribing stand would be a useful addition, you’ll probably need to make up an adapter to hold the indicator but it needs only to be functional.

For me the large surface plate is a real problem. I just don’t have room for it, my shed floor space is full. I’ve just moved out the kids bikes to accommodate the surface grinder. I could possibly find a space to keep one on a shelf under a bench but they aren’t easy to whip out when needed. That’s why I got the 18x12 plate - I have a specific space for it.

I actually have an old scriber stand, earlier I spent some time trying to map my surface plate to see how bad it really is. But it’s all so bouncy and unreliable that after an hour at it I am none the wiser. Each time I return to a square I get a different reading. Of course this could be because the base is not in exactly the same place, but even if it is I often get a different reading.

I do wonder if I should buy another 18x12 reliable surface plate, or even a smaller one and use it as a reference to scrape my existing surface plate,

d7f112d4-cc90-46b1-bc1c-99d1584d94d1.jpeg

Pete Rimmer06/08/2022 22:12:48
1260 forum posts
69 photos

Your setup there will work but it will tend to read what's under the front end of the scriber block rather than what's under the pointer. Shorten it up by pulling the rod back through the clamp a bit.

A basic repeat-o-meter is simple enough to make. I made mine from a chunk of cast iron with the corner cut off and using a stanley blade as a hinge. Took a few hours and it works very well.

repeat-o-meter

Tony Ray06/08/2022 22:53:34
197 forum posts
46 photos

I would give the repeat-o-meter a go first and see if you can improve your existing plate. I can’t see the point of spending money on another plate that is really too small for your needs. I keep mine on the bench and when the plywood cover is in place I use the surface for other things. Although in an ideal world a plate should have its own stand and be set on points the difference between this and sitting it on a solid bench will be very small.

Steve35507/08/2022 07:37:33
259 forum posts
177 photos
Posted by Pete Rimmer on 06/08/2022 22:12:48:

Your setup there will work but it will tend to read what's under the front end of the scriber block rather than what's under the pointer. Shorten it up by pulling the rod back through the clamp a bit.

A basic repeat-o-meter is simple enough to make. I made mine from a chunk of cast iron with the corner cut off and using a stanley blade as a hinge. Took a few hours and it works very well.

repeat-o-meter


Imdeed, I should have thought of this. This setup is functioning exactly like winding sticks in woodwork. It is amplifying any difference between the near and far sides of the base (and then adding on any difference at the location of the probe). In my defence I was just copying 2 experts from YouTube!

I’ll think about how to do this better, the repeat-o-meter looks great, with the snag that the base needs to be surface ground (bit of a problem at the moment!)

Steve35507/08/2022 07:50:26
259 forum posts
177 photos
Posted by Tony Ray on 06/08/2022 22:53:34:

I would give the repeat-o-meter a go first and see if you can improve your existing plate. I can’t see the point of spending money on another plate that is really too small for your needs. I keep mine on the bench and when the plywood cover is in place I use the surface for other things. Although in an ideal world a plate should have its own stand and be set on points the difference between this and sitting it on a solid bench will be very small.


Here’s the thing… last weekend I lashed up a little metalworking bench. The idea being to get all the metalworking equipment out of the woodworking side of my shed, due to grinding dust, oil and grime not mixing at all with woodworking. Had I realised that I was going to want to find a space for a bigger surface plate, I could have done it differently. Here’s a vid of the area, the surface grinder has now moved to a more sensible position. See surface plate in its spot behind the DW.

Metalwork side

 
There may be a cunning plan available where I chop off the top of the bench, weld in a couple more lengths of angle to support a surface plate, and make the bench top removable. It would still be inconvenient/heavy, and the surface plate would be a few inches lower that I would like, but it might work.
 
Such a shame, the bench is 40cm deep. If only it were 50, it would fit a surface plate much better 🤔
 
b20017c5-ab38-455c-9a27-09e7060b3845.jpeg

 

Edited By Steve355 on 07/08/2022 08:14:10

Steve35507/08/2022 10:24:01
259 forum posts
177 photos
Posted by Pete Rimmer on 06/08/2022 22:12:48:

Your setup there will work but it will tend to read what's under the front end of the scriber block rather than what's under the pointer. Shorten it up by pulling the rod back through the clamp a bit.

I’ve had another go at this this morning, and got altogether better readings on my surface plate

DTI on surface plate

Displacement in most places is 0-0.0002 with a few spots that are maybe 0.0005. But it is difficult to do well, and the surface gauge spring is very springy (is this normal? I doubt it) and difficult to adjust accurately. If it slips off the gauge block, it often needs readjusting back to 0. I need a better surface gauge.

The errors are as likely to be me/the setup as the surface plate, I’d say.

The question is, is this surface plate good enough to work with the surface grinder table/ways etc? I wish it was, but probably not. But it isn’t as far out as I feared.

Pete Rimmer07/08/2022 14:07:48
1260 forum posts
69 photos

I you cared to pop down to me in Gravesend I would do a quick evaluation of your plate. You could bring the table and I'd do that too.

Steve35507/08/2022 15:39:55
259 forum posts
177 photos
Posted by Pete Rimmer on 07/08/2022 14:07:48:

I you cared to pop down to me in Gravesend I would do a quick evaluation of your plate. You could bring the table and I'd do that too.


thats a kind offer Pete and I may take you up on it. I’m actually off to the US tomorrow for 2 weeks then another 2 weeks on holiday. So my project is about to be delayed for a month, sadly. But once I’m back, I’ll be raring to get on with it.

I may try to pick up a comparator when in the US, I have an idea for a simplified repeat-o-meter thing.

Tony Ray07/08/2022 17:02:57
197 forum posts
46 photos

“ the repeat-o-meter looks great, with the snag that the base needs to be surface ground (bit of a problem at the moment!)”

I’d be happy to surface grind it for you

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