# The Downside to a Nicely Ground Table... :(



## wrmiller (Dec 7, 2017)

Had to open the curtains near the mill this morning as it's starting to get a bit chilly here. Unfortunately, the glare off the table is so bad I can barely see what I'm doing. The photo doesn't do justice to the glare, but I need to go get my sunglasses!


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## Dan_S (Dec 7, 2017)

Sounds like its time to make some table covers, to protect the top and your eyes.


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## wrmiller (Dec 7, 2017)

Dan_S said:


> Sounds like its time to make some table covers, to protect the top and your eyes.



Good idea...


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## benmychree (Dec 7, 2017)

Also, nicely ground table tops scratch so easily, unlike the old practice of smooth planing them


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## Cactus Farmer (Dec 7, 2017)

I've taken time to engine turn a few shiney surfaces and it sure cut down on the glare plus it looks soooo cool!


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## benmychree (Dec 7, 2017)

Scraping is another cure.


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## wrmiller (Dec 7, 2017)

benmychree said:


> Also, nicely ground table tops scratch so easily, unlike the old practice of smooth planing them


This is true, but fortunately I have only minor scratches to date. Seriously thinking about making some plywood covers for the table.


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## LEM (Dec 7, 2017)

buy some magnetic sheets and cut to fit.  Makes cleanup easy.  White ones work well.


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## wrmiller (Dec 7, 2017)

LEM said:


> buy some magnetic sheets and cut to fit.  Makes cleanup easy.  White ones work well.



Magnetic sheets? I'll have go Google these.


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## hman (Dec 8, 2017)

Brooks Ravenscroft posted this in 2015.  He got them at Home Depot.
http://www.hobby-machinist.com/threads/way-cover-t-slot-cover.37227/


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## [X]Outlaw (Dec 8, 2017)

I was thinking of getting some rubber sheets to protect mine.


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## magu (Dec 8, 2017)

That's just a horrible problem you have there... sunshine and a shiny table.


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## Asm109 (Dec 8, 2017)

Two pieces of 1/16th inch thick Aluminum sheet. Put a one inch bend on the front edge and trim one side edge to fit snuggly to the outline of your vise. Just set them on the table. They stay put and are easy to remove. Also provide an easy reminder of where to locate the vise.


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## wrmiller (Dec 8, 2017)

[X]Outlaw said:


> I was thinking of getting some rubber sheets to protect mine.



I checked into that thick rubber stuff that some folks here use and man that stuff is way to expensive for me nowadays. I found some rolls of 30 cm thick magnetic sheets on Ebay. Apparently some of the thinner stuff is not so good. The magnetic sheets are cheap enough that I can try this  without causing myself too my discomfort.


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## RandyM (Dec 8, 2017)

You don't feel the magnetic sheets will be difficult to clean? Well, it won't be for the non-magnetic materials.


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## wrmiller (Dec 8, 2017)

RandyM said:


> You don't feel the magnetic sheets will be difficult to clean? Well, it won't be for the non-magnetic materials.



That immediately came to mind Randy, but thought I'd give them a try anyway. I am unable to fabricate metal covers as I have no brake or shears. Those were on the list of things to get before I quit working. The untimely layoff kinda put a major kink in the plans I had laid out... 

Such is life.


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## RandyM (Dec 8, 2017)

wrmiller said:


> That immediately came to mind Randy, but thought I'd give them a try anyway. I am unable to fabricate metal covers as I have no brake or shears. Those were on the list of things to get before I quit working. The untimely layoff kinda put a major kink in the plans I had laid out...
> 
> Such is life.



Well, I made mine out of aluminum. I believe 1/4 thick, needed enough thickness for the flat head screws.


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## cjtoombs (Dec 9, 2017)

Besides the glare issue, having half your table heated by the sun and causing a temperature differential (and thus expansion differential) is probably not the best thing for accuracy.  I have always heard that you shouldn't put machine tools where the sun can shine on them for this reason.


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## wrmiller (Dec 9, 2017)

I'd have to look up the coefficient of expansion on cast iron, but as the sun is quite low on the horizon now, and the fact that it (sun) is shining on a 3 1/2" thick piece of cast iron that weighs hundreds of pounds, I am not sure just how much it would throw things off? I'm pretty sure I'd not notice a few tenths (.0001) of expansion as I typically don't come close to attempting that kind of accuracy. Now if I was trying to make my own air bearing... 

I suspect that the ambient air temp delta between early morning (high 30s/low 40s), to late afternoon (low to high 60s/low 70s) would have more of an impact on any accuracy variances in my machines. But again, I suspect that the accuracy delta is under that which I typically shoot for (.001-.0005) when I am trying to be precise. I have learned that I save myself considerable time, effort, and aggravation if I only worry about holding to close tolerances where absolutely necessary, and using 'good enough' everywhere else. I find I have a more enjoyable time in the shop that way. 

But thanks for the heads up.


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## cjtoombs (Dec 9, 2017)

The temperature differential during the day between morning and evening, while not ideal, heats and cools the entire machine evenly.  The sun shining on one end of the table only heats that end, which means there is likely some bending and twisting going on, however small.  Precision scraping straightedges come with wooden handles so your body heat from handling them doesn't warp them during use.  You probably wouldn't see any issue with it with normal parts and on a hobby du tymachine it probably doesn't make any difference.  On a production machine running every day all day long it would likely lead to accelerated wear, as the deformation would lead to rubbing.


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## Uglydog (Dec 9, 2017)

[X]Outlaw said:


> I was thinking of getting some rubber sheets to protect mine.



Drawer liners,

Daryl
MN


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## peder.wennberg (Dec 9, 2017)

RandyM said:


> Well, I made mine out of aluminum. I believe 1/4 thick, needed enough thickness for the flat head screws.
> 
> View attachment 249193
> 
> ...


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## peder.wennberg (Dec 9, 2017)

I did the same but used 1/4" HDPE sheet the supplier cut to size for my 935 table.  All I did was trim for the vise and took some 1/4" aluminum flat bar and machined to fit in the table tracks then secured to the HDPE with flat head screws.


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## wrmiller (Dec 10, 2017)

HDPE: Is that the white boards stuff sold at Home Depot/Lowes?


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## JimDawson (Dec 10, 2017)

HDPE = High Density Polyethylene, think plastic kitchen cutting boards


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## wrmiller (Dec 10, 2017)

Thanks Jim. Found some online. I like the black (marine grade).


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## Doubleeboy (Dec 10, 2017)

I wonder how bad the smell or smoke is if a tan or blue hot chip hits the HDPE board?  Any thoughts?


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## pdentrem (Dec 10, 2017)

Doubleeboy said:


> I wonder how bad the smell or smoke is if a tan or blue hot chip hits the HDPE board?  Any thoughts?



Not an issue. When I was cutting the shafts for the splitter the other week, lots of hot chips were flying about and some hit some plastics in the area and even embedded into the surface, there was no smoke or odor from the plastics. There was a lot of smoke and odor from the oils and coolant though!


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## peder.wennberg (Dec 11, 2017)

X2


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## peder.wennberg (Dec 11, 2017)

I bought my HDPE from Interstate Plastics cut 9" x 35"


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## aliva (Dec 12, 2017)

put some water on the table leave it for a week and the shine will be gone.
Seriously I made wood covers for my mill with an 1/2 edge on 3 sides also embedded small round magnets to keep them from moving


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## 7milesup (Dec 13, 2017)

I really like the idea of using the magnetic covers.  I think a visit to the nearest sign shop may be in order.  They should have that material that they use for magnetic signs that stick to cars/trucks, and I would assume they have multiple color options.


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