Decking / resurfacing large bandsaw table?

[DMucci]

I just picked up an old Do-All bandsaw from the 40’s that spent some time outside. It’s got a big ole heavy cast iron table on it with some bad pitting from corrosion. I’ve knocked most of the rust back with wire brushing and phosphoric acid (metal prep & etch).

I mostly work on motorcycles and it would be great to have a large flat surface like this to sand vintage engine case gasket surfaces on.

My question is, what’s the cheapest way to “deck” this surface so that I know it’s flat? I know I could bring it to a machine shop but I’m assuming they’d charge me a ton to have it done since it’s probably too big to fit on a Bridgeport. It’s a 31” x 31” table that probably weighs around 300 lbs. so I’d prefer to not have to transport it. Is there a way to do this without a mill?

 

[schiada96]

I just picked up an old Do-All bandsaw from the 40’s that spent some time outside. It’s got a big ole heavy cast iron table on it with some bad pitting from corrosion. I’ve knocked most of the rust back with wire brushing and phosphoric acid (metal prep & etch).

I mostly work on motorcycles and it would be great to have a large flat surface like this to sand vintage engine case gasket surfaces on.

My question is, what’s the cheapest way to “deck” this surface so that I know it’s flat? I know I could bring it to a machine shop but I’m assuming they’d charge me a ton to have it done since it’s probably too big to fit on a Bridgeport. It’s a 31” x 31” table that probably weighs around 300 lbs. so I’d prefer to not have to transport it. Is there a way to do this without a mill?

Lapp ? I’d take it to a grinding shop they would be the most cost effective solution I’d bet,


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[MushCreek]

The best way is to Blanchard grind it. That's how most of them are done at the factory. I have no idea what they would charge to do this. It would probably be cheaper to find a used granite or iron surface plate to lap your engine cases on, and just use your band saw as a band saw. A surface plate will be much, much flatter and more stable than a saw table.

 

[Htscheg]

Grind it or as stated above find a surface plate

 

[seber]

You aren't looking for perfection an a surface here. Go to a granite countertop place and pick up a sink cutout. Often free, nominal cost at most. Grinding that plate will not be inexpensive.

 

[matt_i]

You can hand scrape it. That's pretty cheap.

You can spot/print it on a surface plate.

You will be in great core and upper body shape at the end.

In excellent form it will be better than a blanchard ground surface.

In lesser form it will still be within a couple thousandths.

The crosshatch pattern will be unlike any other.

 

[DMucci]

Well the local quote I got to have it Blanchard ground was $220. More than I was hoping to spend.

I’ll look into hand scraping. I’m not familiar with it.

I know I can get a granite plate I’m just running out of places to put stuff like that in the shop. It would be nice to knock out two birds with this thing that’s already taking up a lot of real estate.


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[MushCreek]

Bear in mind that hand scraping will take a long time, and it takes some skill. Also- you need a reference surface, such as a surface plate to scrape it to. I once scraped in three large cast iron surface plates. There's technique to scrape them to each other until all three are flat. I stopped keeping track at 100 hours.

 

[RTM]

What about getting the granite countertop piece mentioned above about the same saw as the saw table, And put it on it to use, and on the ground vertically behind it when not?

 

[Mohawk Dave]

I'm with the granite scrap piece.

Fill holes or divots with Devcon metal filler $$$ or Permatex metal filler $, then whetstone high areas, then buy lapping compound and do figure 8s on the granite. Dykem table prior to lapping on granite.

This is assuming it's pretty damn flat already...

 

[MushCreek]

One shop I worked for had a couple tables made out of granite 'seconds' from a gravestone maker. Apparently, they're pretty flat, and thick enough to be stable. They're also mighty heavy.

 

[Andy1234]

Well the local quote I got to have it Blanchard ground was $220. More than I was hoping to spend.

I’ll look into hand scraping. I’m not familiar with it.

I know I can get a granite plate I’m just running out of places to put stuff like that in the shop. It would be nice to knock out two birds with this thing that’s already taking up a lot of real estate.


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I hate to say this, but $220 sounds like a really good price to grind something that size. When I started reading this thread my initial thought was that grinding that table would cost $500 or more.

 

[Mohawk Dave]

I hate to say this, but $220 sounds like a really good price to grind something that size. When I started reading this thread my initial thought was that grinding that table would cost $500 or more.

And I bet by the time you source and pick up granite scrap, buy and set metal filler,stone it,lap it.... he'll be in 12+ hours of his time easily. So,OP, gotta ask yourself what your time is worth.

Sometimes I have more money than time and other times I have more time than money.

 

[2oolhound]

You're looking at this wrong. Do-all band saws are worth a fortune. Get it working and sell it then go out and buy a blanshard ground plate. Surface plates are made for measuring not lapping things flat. Post photos of the complete saw you have.

 

[Spacey_G]

My impression is that $220 is a hell of a bargain compared to the amount of work you'll put into flattening it yourself. I would take that shop up on their quote in a heartbeat.

 

[DMucci]

I agree, the hand scraping sounds like way too much work.

I’m already planning to spend hundreds getting this bandsaw back into working condition and the added $220 it’s really putting it over the top.

..I suppose I could sell some lesser used tools/ machines but it always pains me so. Even if they’ve been collecting dust for 5 years

 

[seber]

We had a toolmaker hand scrape a mill bed at work. Eight hours a day for about a month. Then one day it was right. I'm not sure how that compared to a new bed but he wore out a bunch of scrapers and wouldn't doubt, his back.

 

[MushCreek]

You're looking at this wrong. Do-all band saws are worth a fortune. Get it working and sell it then go out and buy a blanshard ground plate. Surface plates are made for measuring not lapping things flat. Post photos of the complete saw you have.

Band saw tables aren't made for lapping things on, either. If you lap directly on it, the flatness you worked or paid for will go out the window. I've lapped things like small engine cases on a piece of emery cloth on a surface plate. As long as you keep things reasonable clean, it won't hurt it. They do make real lapping plates, which are basically a cast iron surface plate with grooves cut into it so the abrasive has somewhere to go. They still wear out, and have to be resurfaced periodically,

 

[DMucci]

Band saw tables aren't made for lapping things on, either. If you lap directly on it, the flatness you worked or paid for will go out the window. I've lapped things like small engine cases on a piece of emery cloth on a surface plate. As long as you keep things reasonable clean, it won't hurt it. They do make real lapping plates, which are basically a cast iron surface plate with grooves cut into it so the abrasive has somewhere to go. They still wear out, and have to be resurfaced periodically,

I don’t lap directly on the metal. I put down adhesive backed sandpaper and wet sand the gasket surfaces.

 

[Kevin54]

Get some Devcon and fill the pits. Then get a stone, WD40, and stone the complete surface working all around the surface in various directions. The WD40 will keep the stone lubricated and prevent debris buildup. I used to stone aluminum before grinding it on a surface grinder all the time.

 

[ez-duzit]

My 12" x 18" granite micro flat only cost me ~$50 on eBay. Your bandsaw table does not need to be that flat. Don't waste your time and money trying to "kill 2 birds with 1 stone".

 

[2oolhound]

I know I can get a granite plate I’m just running out of places to put stuff like that in the shop. It would be nice to knock out two birds with this thing that’s already taking up a lot of real estate.

Sorry, I thought from your 1st post you were scrapping the bandsaw and were trying to salvage the table for lapping.

Band saw tables aren't made for lapping things on, either. If you lap directly on it, the flatness you worked or paid for will go out the window. I've lapped things like small engine cases on a piece of emery cloth on a surface plate. As long as you keep things reasonable clean, it won't hurt it. They do make real lapping plates, which are basically a cast iron surface plate with grooves cut into it so the abrasive has somewhere to go. They still wear out, and have to be resurfaced periodically,

This is basically what I was saying. Don't use the table for lapping and don't use a surface plate for lapping either. (that's why they make 2 grades of surface plates, they know what will happen in a toolroom). Lapping plates are made out of a variety of metal types. I think there are even ceramic ones. Lapping tables have grooves cut in for the slurry to escape. Do a youtube search for making lapping plates for a ton of info on them.

These solid lifters were resurfaced on a lapping plate. The tips are stelite and was done using an angle plate to stay square to the back which was polished 1st.