A Handplane Rehab #1: A Twisted Sole and a Crooked Frog

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This is part 1 in a 6 part series: A Handplane Rehab

  1. A Twisted Sole and a Crooked Frog
  2. Sandpaper is Good for the Sole
...
  1. Stick a Fork in it!

I bought a Millers Falls 24C jointer plane off Ebay a few months ago to fill out a missing slot in my till. The 24 is the size of a Stanley #8 and is relatively hard to come across. So when I stumbled on one shortly after it was listed that was a price I was willing to pay, I was tickled and bought it immediately. The only downside to it was that the iron was a Stanley iron instead of an OEM. That was remedied when I found a NOS Millers Falls iron on Ebay for a decent price and passed the Stanley along to a fellow LJ to offset the cost a bit


I am tackling this rehab in a slightly different order than I normally do. Typically, flattening the sole of a plane is the last thing I do to it. But in this case, I happened to be flattening the sole on my Millers Falls #22 plane at the same time the #24 was delivered. So I figured while I had my large granite plate, spray adhesive and sandpaper out, I might as well go ahead and do the big brother as well.


The 22 cleaned up quick. The 24 however is a different matter… After many sheets of 80 grit paper and several hundred strokes, a pronounced twist is still evident in the sole.


My marker lines were cleaned up from the entire sole other than the left side of the heel and the right side near the toe.


I proceeded to lap the sole on the granite plate with sandpaper for a while until I thought maybe there was an underlying problem causing such a severe twist? It's very unusual to have to go to this much effort to flatten a sole but I've also never had a plane this large so maybe it's not that unique of a situation? 

I wasn't sure so I decided to jump ship for the time being and investigate to see if I could find any underlying issues. So I tore the plane down to its component parts. 


I gave the main body a good looksee to see if there were any small cracks or casting defects that I had missed initially. Didn't find anything. So I decided to go ahead and jump to checking the fit of the frog with the body.

I won't go into too much detail on printing and scraping the frog here. You can read more about it at the linked post above if you wish. But, I did find some issues that needed resolving.

First thing I did was clean the machined pads on the frog and body with a Scotchbrite pad and some WD40. I just wanted to be sure there was no debris or grease on them.


Then I made sure there were no burrs or obvious raised/dinged areas on the machined faces. There were a couple of things with the machining that I don't love to see. First, on the frog, the rear pad was raised on one side and pretty much flush with the rest of the casting on the other.


This in and of itself isn't an issue as long as everything else seems to be machined with reference to that (which it does). There could be some concern of that causing an improper fit on the mating surface of the body. But, we'll see in a bit, that's not the case here. So, while it's not ideal I also don't think it's a detriment and I don't think it'll cause me any issues.

The pads in the body where the front "feet" of the frog mate are also not machined the way I'd like them to be. They're roughly flush with the cast surface behind them and recessed slightly in some sections. They're fully recessed when the enamel is added.


This can be a real issue in practice because it can limit the adjustability of the frog position. Particularly if one were to use an aftermarket iron that was significantly thicker than the OEM blade. The frog would need to be moved rearward which could result in the milled feet on the frog ending up on the cast/enameled surface rather than the machined pads. Just something to keep in mind when reassembling and fettling the plane.

I'll toss this in here too. I don't know if all manufacturers did it the same way but I'm not disheartened by the pads in the body being milled below the cast surface sometimes because I know it was within the design tolerances. How do I know? I'm glad you asked ;-p See how when the pad isn't raised on this frog there's a little section between the pads where it doesn't clean up due to the radius of the milling cutter?


Well, if the frog's front feet were full width they would hit that and wouldn't be able to sit flat on the milled sections. So Millers Falls accounted for that in the frog casting by casting a couple of cutouts on the inside of the feet to give clearance for that raised center section.


Anywho… While the machining isn't exactly what I want to see, it's not bad and I don't foresee it causing me any issues with the assembly or fettling of this plane. So I'm comfortable with my visual inspection of the frog and base. Now time for a little more technical inspection.

I painted a thin coat of dye on the machined faces in the base.


Then I printed the mating pads of the frog. You can read more about the methodology in the blog post linked earlier. Here is the result of the initial printing:


Good solid contact on the rear pad and the left foot but very little on the right foot. It's unusual for me to see a fit this poor. Just to be sure, I scraped the thick enamel away around the machined pads in the base to be sure the foot wasn't being prevented from sitting all the way down.


I repeated the print and got the same result. So I pulled out a small carbide inserted scraper and started scraping away the dyed sections on the left foot. I left the rear pad alone.


Second print got me a little more contact on the right foot.


I scraped the high spots down on both feet. You can tell which spots have been scraped and what's just the machined surface. The scraping is very minimal and localized.


Third print is better and I know I'm getting close.


I scraped the high spots one final time and the fourth print satisfied me.


I know it looks kinda spotty but that's okay. There are large sections of both feet and the full width of the rear pad making solid contact which is all I need. Also bare in mind that the printing is done with no pressure applied to the frog, its own weight is all that's pushing it into contact with the base.

So now I can be confident that when the screws are used to fix the frog to the base, it will make solid contact without having to deform or induce any stresses in the base. Was the poor fit between the frog and the base what caused the twist in the sole? I don't know yet, I haven't reassembled it and went back to lapping. But, I think it's highly unlikely. I didn't have to scrape much material at all off the feet of the frog. The fit wasn't terrible and I don't think it was sufficient to pull the base into a significant deformation. We'll see when I get back around to lapping though!

Since I'm already on the frog, I may as well wrap that part of the rehab up. Next thing I did was to make sure the bed was relatively flat to ensure that my blade doesn't get deformed when the lever cap pulls it down to the frog face.

The lateral lever prevents me from being able to just print the frog directly on my granite surface plate. And I don't want to remove the lever unless absolutely necessary. So I use two precision ground parallels that I know are the same thickness and paint dye on them to print the bed face.


I lay the frog down gently.


And pick it straight back up.


There appears to be a slight recess on the top right and center left areas. I don't scrape this face because it's just not that critical. I address it with a flat file concentrated on the high areas.


A little quick filing and another print and it's good enough for government work.


Again, it looks uneven and spotty. But as long as there is die transfer over enough of the surface that I can be confident that it won't deform my iron significantly, I'm happy with it.

That'll do it for this installment. Now that I have the plane tore down I'm going to proceed with painting and cleaning up all the hardware. I won't be documenting that in this series since I covered it all in detail in my previous series and my methods haven't really changed much in regards to those tasks. This plane is my desired type (Type 2) in that it has the brass hardware and Cocobolo tote and knob. The horn is missing from the tote so I may do the next entry on repairing that. We'll see! I have no idea when the next entry will be coming since I don't know when I'll be working on the plane. But you'll know when I know ;-)

Thanks for reading!