Jack plane mouth clearance

[scooby]

I got a Hock iron for my jack plane (bailey 5 /2) and tried it in my plane with the original cap iron. Even with a very small amount of hook, the throat clearance is tiny. It's an old plane that I inherited as such and never took any notice of the clearance with the original iron (which isn't here). I don't have any other planes here to reference from so I don't know how much clearance I need.

It's a bit of a tough question to answer ,and might be a bit subjective, but could someone tell me how much clearance there should be? I went to adjust the frog back a bit and found it had already been wound right back already so I think I need to do a bit of mouth filing :? I've also expecting a hock chipbreaker to arrive, so will this require even more clearance?

Thanks

 

[Philly]

Scooby
You need to file the mouth wide enough to take the thickest shaving you expect to take. Remove the blade, clamp the plane vertically and file the mouth evenly. Make sure you keep the mouth square (mark it out first).
If you make the mout too wide you can take up the slack by moving the frog.
Don't forget to file a slight back angle to prevent shavings jamming.
David Charlesworth has a chapter on this in his first book-well worth gettting!
Hope this helps
Philly

 

[Anonymous]

Don't wish to teach you to suck egss, but did you move the frog back? The new blade is thicker.

I have fitted a Hock blade to a #4 and #5 Stanley and simply moving the frog back was enough. Also fitted a LN #5.5 blade (seriously thick) to a Stanley #6 without need to file the mouth once the frog was moved back

 

[bugbear]

clamp the plane vertically and file the mouth evenly. Make sure you keep the mouth square (mark it out first).
If you make the mout too wide you can take up the slack by moving the frog.
Don't forget to file a slight back angle to prevent shavings jamming.

I find it easier to clamp the plane at the back angle, so you're filing
horizontally.

BugBear

 

[David C]

Philly,

Thanks for the book ref!

I have occasionally come across some old planes which need a little throat filing.

As long as the front edge of the chipbreaker is sharp and not prepared steeper than 45 degrees, there will be no additional tendency to choke, with the Hock chipbreaker.

The thickest shaving you wish to take?
Softwood--"Shavings as thick as belts".
Hardwood--a full width 6 thou" shaving is hard to push!
If used as a scrub plane with heavily cambered blade, maybe you can take 1.5mm?
These ramblings purely to indicate that you need to decide what you will be doing with the plane, in order to select an appropriate mouth width.
My 5 1/2 is set up as a super smoother and the mouth is barely 4 thou".

I am shooting a Bailey plane tuning DVD here next week, but don't expect it to be available for a while....

best wishes,
David

 

[Mirboo]

Even with a very small amount of hook, the throat clearance is tiny.

I'm not sure what you mean by hook? :shock: I haven't heard of Jack plane blades being prepared with a hook, only scraper planes. :?

 

[scooby]

Even with a very small amount of hook, the throat clearance is tiny.

I'm not sure what you mean by hook? :shock: I haven't heard of Jack plane blades being prepared with a hook, only scraper planes. :?

Hook is the amount of iron potruding past the sole. More hook= thicker saving, less hook = thiiner shaving. I, and all the joiners I know or taught me at college called it hook. I thought everybody called it hook :?

 

[David C]

Ah......joiners......new terminology for me....

Where did you go to college please?

David

 

[scooby]

Ah......joiners......new terminology for me....

Where did you go to college please?

David

Bolton college in Lancashire

 

[Mirboo]

Hook is the amount of iron potruding past the sole. More hook= thicker saving, less hook = thiiner shaving. I, and all the joiners I know or taught me at college called it hook. I thought everybody called it hook :?

Ahhh! I hadn't heard that terminology before. Your original post makes sense to me now.