how much taper on mould plane irons

[ronald mccormack]

I've been making hollow and round moulding planes and one conical escapement rabbit plane. For the planes I made so far I used pre made blanks from lei Nelson but do to changing financial circumstances I have had to make my own for the rest of the set I'm making.
So I've cut all the blanks out and its going good but the question is how much taper do these planes need to work at there best. The LN irons taper down 1/8 to 1/16. Is this much taper necessary?

[Adam Maxwell]

You can use untapered irons; the hollow and round irons I've made have only a very light taper, so they're not as easy to release by tapping them through, and you may have to tap the wedge a bit harder to set them. I've had no problems in actual usage, but YMMV. If you search google for "storify maxwellarm molding plane", the first search hit shows how I made and tapered my irons, but the images take a long time to load.

[David Weaver]

Very little taper is needed. A 32nd is probably all I've got on mine, and they work far better than no taper.

I don't do anything exact, I just put them in a jig and belt sand them.

[ronald mccormack]

That's about how I did my first one. I put a LN blank next to it and scribed the taper but that's a lot of metal to remove. I don't know if this matters but should the taper be on the face or back of the iron. I assume the back were the wedge makes contact but its hard to tell on the LN irons.
Thanks for the responses so far.

[David Weaver]

If you don't remove too much, I doubt it makes much difference if it's on the back or the front of the iron. Conceptually, it's nicer to me for it to be on the front so that I have a precision ground side of the iron against the bed in back.

I would kind of rather have the tang a bit thicker if the wedge comes out easily, anyway, because it's going to be struck by a hammer and it's unhardened, so less taper seems nicer to me.

There may be a reason that the vintage irons had a lot of taper, and it may have more to do with being blacksmithed. I haven't had any trouble with my irons being stuck, nor with them not keeping their depth setting appropriately.