Scraped cast iron surfaces in woodworking?

[Steve Mathews]

Scraped cast iron surfaces on machine tools are commonplace to achieve flatness but I have never seen it used on woodworking machines or tools that require a flat surface. I realize the scraping provides a path for oil to flow between two surfaces but it also provides less contact between them resulting in less friction, which should be a benefit in a woodworking environment. Rob Cosman uses wax on his bench planes to reduce friction. I wonder if the bottom of a plane is scraped would produce the same result.

[Bill Dufour]

A scraped surface will have more contact and more friction since you are shaving off the high points and letting them get closer together. Wood working does not need the accuracy of scraped surfaces. For a wood worker one thousandth of an inch is accurate no need to look for 100 or 1000 spots per inch like a scraping job will yield.I doubt most wood tools are supported well enough to stay that flat under load. In wood working 1-3 thousandths is considered super accurate. i bet a cut surface moves more then that within 15 minutes of machining. Today most machine tools are just ground and not scraped. Modern grinding plenty good enough for wood working. At least to start the process. A good surface plate large enough to do a tablesaw will cost a good bit. grade A 36x36 will cost about S1,000 which seems too cheap to me.
How many folks even bolt there wood tools down? I know of no wood machines that have provision for jacking bolts to twist them into alignment anyway.
Bill D.

I think the Op meant frosting which is applied after scrapping as a decoration. It will retain some oil and also grit which may cause moving surfaces to wear faster unless fully enclosed and not visible. Some machine. resellers do a quick flake job to make the ways appear unworn to the unknowing buyer. very similar to used car dealers doing a paint compound polish job and oiling the tires and upholstery to look new and shiny.

[Rod Sheridan]

I have a couple of corrugated sole planes, they reduce friction.

All my cast iron tools are waxed whether they're hand tools or machines...........Rod.

[Mark Bolton]

As Rod said, corrugated surfaces, or on large tables planed surfaces are often looked at for reduction of friction. Scraping in the metal world serves a ton of purposes (extreme flat and parallel, as well as oil retention like you mention). The main issue, same as in the machine world, is cost. Its simply not cost effective in the wood world. The concept would be correct that XX, or XXX points per inch of contact would technically be less contact area (friction) in a wood setting but you'd also have to consider that wood, even very hard wood, is flexible and on a scraped surface where the difference between a high and a low may be far less than a thou, your gain vs. cost would be zip.

Order a hand scraper and scrape one in for fun. I'd think youd have to do some adjusting from the standard scraping techniques in the metal world and most definitely avoid things like crescent scraping to avoid creating a directional surface that would influence a hand tool.

Most that I have ever seen have even say the massive reduction in surface area of a corrugated hand plane is hokum and pretty much imperceptible to the user as compared to a clean/well waxed smooth surface. Wood and metal machine surfaces arent the same animal but Id guess it'd sure be pretty to see a beautifully scrapped sole on a handplane sitting on your bench :D

[Patrick Kane]

I know next to nothing about scraping; however, i thought Tannewitz scraped their tops? Ive seen a few Tannewitz table saws in person and they have a surface texture/appearance different to anything ive ever seen.

My jointer tables and T17 have planed tables in the direction that you feed material. I know guys say this is very beneficial because the wood floats on the ridges of the metal planer marks, but i dont know if i notice a difference or not. They look cool, and it speaks to an older/better(maybe?) method of flattening cast iron, but a blanchard ground surface with paste wax on it is already pretty slick. I think back to the corrugated plane soles. If that was an enormous improvement in performance, why are Lee Valley and Lie Nielsen not producing a corrugated sole today?

[Mark Bolton]

I think back to the corrugated plane soles. If that was an enormous improvement in performance, why are Lee Valley and Lie Nielsen not producing a corrugated sole today?

This has always been my take-away from peoples comments that corrugated soles were a hokum sales pitch at the time.

The coefficient of needed force to be applied as opposed to the friction at play seems to put anything other than a sticky rusted pitted surface akin to sticking sand paper to the sole, as an inconsequential gain in production.

[Phillip Mitchell]

The Tannewitz tables are not scraped. I think the process was done with a wobble wheel on a large surface grinder and the table tops were tilted at an angle during grinding. I think it was done largely for decoration and sizzle, but it does look pretty sexy.

I have a ‘40s era Tannewitz Model U table saw and the frosting still looks nice on it even though there is a quite a bit of patina on the cast iron at this point in its life.

[Brian Holcombe]

Planed tables are great, especially by comparison to ground tables.

[Wes Grass]

Dont remember what brand (metal working), but the top table surfaces were 'scraped' for appearance with a power scraper mounted in a cnc machining center.

[Andrew Seemann]

A scraped surface on a woodworking machine is beyond overkill. The cost of scraping a table saw top would likely exceed the cost of the entire table saw (including the Blanchard grinding). And it would give the machine no increase in accuracy, as the top isn't thick enough and the body isn't rigid enough to keep the level of accuracy that scraping would give. Scraping is for tools that need their tolerance measured in ten thousandths or maybe thousandths over several feet. Woodworking machines are done maybe to 0.005" - .010" and they work just fine with Blanchard grinding and that level of accuracy.

I could see something like an old Northfield jointer maybe having a planed top, but not a scraped one.

The machine shop I used to work in had a 3 foot by 7 foot cast iron surface plate/workbench with a hand scraped top, probably WWII Navy intergovernmental surplus. I don't know how thick the top was exactly, but I assume it was at least several inches thick so it didn't sag. It had to have weighed several tons. I can't imagine what it would cost to buy something like that new today.

As for scraping a hand plane, see "scraping a woodworking machine" above:) I'm surprised no one has offered it. It would be a way to massively increase the cost and status level of plane with no increase in utility. If anything, the extreme flatness would probably make the plane stick to the wood more making it harder to use.

[Brian Holcombe]

I think you all may be mistaking a 'flaked' surface with a scraped surface. Flaking is a surface prep done for oil retention, not necessarily related to scraping and often done over a ground surface. The table and ways of a Bridgeport mill are a good example of this.

A surface scraped for flatness will have a similar surface but it will have typically been done by hand with or without a power scraper and they are aiming at a specific number of contact points per inch, checked against a surface plate.

I could see flaking being pretty useful for a woodworking surface to break up the surface tension.

[Mark Wooden]

I've worked on several machines that had areas scraped by a machinist to get rid of variations in tables and beds- a shaper, jointer and a planer come to mind. It used to be a viable alternative to taking large cast iron parts to a shop and have them ground or planed to correct a relatively small area.

[Mel Fulks]

I've worked on several machines that had areas scraped by a machinist to get rid of variations in tables and beds- a shaper, jointer and a planer come to mind. It used to be a viable alternative to taking large cast iron parts to a shop and have them ground or planed to correct a relatively small area.

Mark's post matches what old timers told me about scraping. They said some of the guys were itenerant and would go to
wood working "mills" ( big places,often several storys ,that mainly made stock items ,but also did custom stuff),and
seek work. Fix could be for ligitimate wear or to repair damage done by some incompetant ,who had mysteriously
disappeared.

[Joe Jensen]

I have a 1970s era SCM jointer. The tables are ground in a way the created ridges maybe 1cm apart. This enables the wood to slide more easily. If perfectly flat, wood would be hard to slide.

[Jim Becker]

Joe, my FS350 J/P has that same kind of grind on it...very helpful once wide stock gets flat as it keeps it from sticking to the metal surface as you try and push it through the machine. I have the impression that scraped surfaces are something completely different.

[Frank Pratt]

I have a 1970s era SCM jointer. The tables are ground in a way the created ridges maybe 1cm apart. This enables the wood to slide more easily. If perfectly flat, wood would be hard to slide.

Could that have been surfaced with a shaper? Not the woodworking kind of course, but the metal machining kind. YouTuber Abom79 has several videos where he uses one & it sounds like that surface that you speak of.

[Curt Harms]

I have a couple of corrugated sole planes, they reduce friction.

All my cast iron tools are waxed whether they're hand tools or machines...........Rod.

My Jet JJP-12 has that corrugated finish, I'm certain it's not as finely done as Euro gear. When I first got the machine (I bought it sight unseen based on Youtube videos) I saw the 'corduroy' finishes and thought "what did I just do"? but it has worked out well. I did spend some time with steel wool and paste which got rid of some minor roughness. It's pretty easy to push wide boards over the jointer so I guess it works.