Thought on fitting a frog to plane body

Re: Thought on fitting a frog to plane body

Richard Gillespie

>I just finished grinding several frogs (30) on a variety of planes.

In my opinion, the critical contact point between the blade and frog is the lower half of the frog. I removed the lever cap screw and used 80 grit emory cloth, glued to plate glass, to grind that portion of the frog from the blade height adjustment tab to the bottom. The metal of the frog with one exception was hard enough to quickly wear out the emory cloth. The exception was that one of the planes had an aluminum frog. That one quickly clogged the cloth.

I think you would have to do an awful lot of grinding with valve compound to get the frog flat.

Re: Thought on fitting a frog to plane body

Steven McKinley from Calgary

>Ahh, see now you said grind the frog until it's flat. With the valve grinding compound, I was thinking that perhaps they (frog and mating base) would grind themselves into a matched shape. If you achieved a complimentary fit, would it be as good as being flat?

I think I'm getting a little esoteric on this.

Steven.

Re: Oops!

Richard Gillespie

>Just realized that you were talking about mating the frog to the body. My earlier reply doesn't address that point. Sorry!

I use the same system I pointed out on the bottom of the frog also. I haven't attempted to work on the mating half of the base other than to remove any rust.

Re: Thought on fitting a frog to plane body

Bill Houghton, Sebastopol, CA

>Lapping in, as the procedure was called when I worked on cars more than I do now, can be effective, but it depends on your being able to manipulate the object being moved in a regular and rhythmic pattern. The amount of movement possible of a frog on its mating base is pretty limited, and I would worry about making things worse. Better to file carefully, fit and test, file again, etc.

You can get machinist's compounds for this, though I've also heard of people using lipstick and carbon paper.

Bill, talking as if he had done this a lot but he hasn't, really.

Re: Thought on fitting a frog to plane body

CJ McLaughlin

>Use artists oil paint. You can use any color that shows up on the metal, though I hear that Prussian blue is traditional. Its still a mess.

One thing I've learned, but that I've not learned how to correct, is when to stop. Its a lot of fun to wreck a blade bed by filing off little blue spots. NOT.

cj

Re: Thought on fitting a frog to plane body

Mike DeHart, South Jersey

>Lapping the frog to the base with abrasive compound will make a bad fit better, but it will not make a good precision fit. The lapping motion will grind more material from the center of the mating faces than it will from the edges since the edges are in occasional contact while the centers are in constant contact. Filing will similarly make a bad fit better, but that has a tandency to remove a little more material from the edges than the centers since you cannot hold a file perfectly flat at all times. I tried all sorts of things to eliminate chatter in one #4 including filing, lapping, and glueing SiC sandpaper to the frog and base alternately so only one face was worked at a time. The chatter remained until I learned to hand scrape the mating parts.

Hand scraping is not particularly hard. It can remove as much or as little material as you need, depending on how near finished you are. Scraping will also make it possible to make the mating surfaces parallel with the bottom of the plane, something lapping and filing cannot do. Scraping tools can be made from old files in any size needed. A scraper is essentially a one-tooth file. I have scraped some post war planes where the frog/base fit was disgusting- two points of contact with the frog literally rocking back and forth. The procedures were described in great detail in a prior forum. I do not know if a search of WC will turn up anything on hand scraping, but it may. The basic tools are a scraper, a gauge block to serve as a reference precision flat surface, a dial indicator, and some type of marking media. The marking media is ideally "high-spot blue" or equivalent but I have also used candle soot and colored markers.

I can go into the actual details of scraping if you need me to, but I don't have the time right at the moment. Try a search and see if this has been covered already. Perhaps I could put together a detailed procedure with the help of a neighbor (one creek over) who can take digital pics and knows how to post them.

Re: Thought on fitting a frog to plane body

Frank D.

>Hi Steve,

I've ground the frog and the part of the body that supports it on a few planes. My method is crude compared to Mike's: I just use permanent black marker, mark all surfaces that go together, then fit them together and move them around ever so slightly. When you take them apart, the bare spots (shiny) are high, so you could just scrape those, but I used a Dremel with a small ceramic grinding bit. After redoing this around 20 or 30 times (you don't want to grind off too much...), I had just about a perfect fit, with all the marker coming off when I rubbed the mating parts together. They don't have to be flat nor parallel to anything in particular, just in full contact with each other.

FWIW,

Frank D. in Montreal

Re: Thought on fitting a frog to plane body

paul womack

>Try a search and see if this[Scraping a fit between frog and body] has been covered already.

IIRC Stephen Thomas (of plane making and tuning fame) covered this back on Badger Pond, and spoke

in very positive terms of the results.

Assuming there are no copyright issues, perhaps someone could repost this, or make it into an article?

BugBear (who misses being able to link to old Badger pond posts)

Re: Thought on fitting a frog to plane body

Mike DeHart, South Jersey

>Actually, it was Stephen Thomas' dissertation on Badger Pond that I was referring to and that was where I first got the nerve to try it. I didn't know if specific references to BP would be frowned upon. I'm sure someone could pull the thread from the archives.

Re: Thought on fitting a frog to plane body

William R. Duffield on the Cohansey

>Mike, That's a great idea. When do you want to do it? I'll bring the camera, a pocket full of batteries, and I've got a Guinea pig of a postwar #5 we could makeover into a silk pursestring.

Oops, never mind...

Frank D.

>I just reread Mike's post and realized that if the two surfaces aren't totally flat you can't adjust the frog without losing contact between them. Darn!

Frank

Re: Thought on fitting a frog to plane body

Mike DeHart, South Jersey

>I have the tools, the blue, and the barley pop. Winter is a great time for indoor R&D. We should be able to do the plane and the pics in one evening. I'll call you next week. Could this become an article?

On the other hand..

Mike DeHart, South Jersey

>Using the permanent marker is how I scraped my first planes until I could score some proper hi-spot blue. Using the marker you darken the entire surface that you will scrape, rub your reference flat gauge on it, and scrape the shiny spots. With the blue (or soot, or lipstick) you put the blue on the reference, rub the workpiece, and scrape the blue spots. The blue tells the story just a little more clearly.

Re: Thought on fitting a frog to plane body

William R. Duffield on the Cohansey

>Yes, I think we should make it into an article for WC. I have a couple of friends who live down the street who are also very interested in old handtools, especially planes. Allright if I ask them if they want to participate? Like me, they are amateur Woodenboatwrights, Colonial Housewrights and Curmudgeons.

Remove NOSPAM for new email address

Could this become an article?

Wiley Horne--Glendora CA

>I hope so. I'd sure like to see it. Maybe even an expanded article to include Stephen's earlier thesis from the BP archives.

Wiley

Re: On the other hand..

Frank D. in Montreal

>AH! And I thought they worked the same way...Thanks for the explanation.

How can you be an amateur curmudgeon?

Bill Houghton, Sebastopol, CA

>Isn't that a full-time professional commitment?

Re: How can you be an amateur curmudgeon?

William R. Duffield on the Cohansey

>It's the dedicated amateurs that push the state of the art. The professionals are too busy acting curmudgeonly about their shop and their neighbors and their dogs, and their grass, and the bugs, and the weather, and the roof and the paint and the plaster, and politics, and taxes, etc.,that they just don't have time or the desire to develop new forms of grumping and grumbling or to enhance the traditional forms of cantankerousness in areas where real progress needs to be made. For example, how long has it been since you've seen Oscar the Grouch find a new way to grump about a new situation? All you ever hear is "Go Home!"

Re: How can you be an amateur curmudgeon?

William R. Duffield on the Cohansey

>...and, I haven't gotten my "Professional West Jersey Curmudgeon" certification from Adam, yet!

Re: Thought on fitting a frog to plane body

Mike DeHart, South Jersey

>I think that would be a great plan. Will my half of the basement hold that many amateurs? Do amateurs take up more or less space than professionals? I'll be out of town this weekend but next week I can clean up the shop(?) and we can do some scrapin', picturin', documentin', articlein', and tastin'.

Besides, I like showing off the skiff-boat, too.