Applying Vaseline/Lanolin to the flesh side of leather

[tsunkasapa]

Look into vg tan sheep. Muc thinner and far more supple than beef. You may want to 'break it in' a bit, but I use it for linin holsters and it is very 'bendable/foldable'.

Or kid skin.

[Tugadude]

I don't think you want the material to be too floppy.  Thin veg tan should roll up very nicely and can resemble an old map.

[simo289]

I had a play with some 2-3 oz that I have, but it's far too thin to take a good tooling impression, my swivel knife cuts almost all the way through! Obviously, that isn't how maps were done, but I like the idea of it having a bit more tactility than ink.

[doubleh]

My personal opinion is that vaseline has place on leather. You can fix your swivel knife problem with simply applying less downward pressure while cutting.

[Tugadude]

3 hours ago, simo289 said:

I had a play with some 2-3 oz that I have, but it's far too thin to take a good tooling impression, my swivel knife cuts almost all the way through! Obviously, that isn't how maps were done, but I like the idea of it having a bit more tactility than ink.

This is one instance I think where a laser would come in handy.  If you took a piece of 1 oz. veg tan and had it laser-engraved and then dyed to suit your purposes it would look fantastic.  Roughen it up some to give it the look of actual aging and you're set.

[chuck123wapati]

4 hours ago, simo289 said:

I had a play with some 2-3 oz that I have, but it's far too thin to take a good tooling impression, my swivel knife cuts almost all the way through! Obviously, that isn't how maps were done, but I like the idea of it having a bit more tactility than ink.

i cant help but ask if you know how maps were done why are you trying to do them differently? If for one of those reenactment things someone will surely call you on it. 

[fredk]

19 hours ago, simo289 said:

I had a play with some 2-3 oz that I have, but it's far too thin to take a good tooling impression, my swivel knife cuts almost all the way through! Obviously, that isn't how maps were done, but I like the idea of it having a bit more tactility than ink.

Depending on the era and the need ancient maps were drawn on vellum, parchment or paper using graphite or waterproof ink

If yours is to be a fantasy map, will it be like a basic treasure seeking map?

An idea; rather than cut into the leather, cut very thin leather (about 0.5mm or less) and apply that to the surface of your thin leather base. Long thin strips for roads and rivers, shapes for lakes or forests, AAA shapes for mountains, all coloured/dyed appropriate colours, Shouldn't take any longer to glue the parts on than it would cutting and tooling it

[tsunkasapa]

23 hours ago, simo289 said:

I had a play with some 2-3 oz that I have, but it's far too thin to take a good tooling impression, my swivel knife cuts almost all the way through! Obviously, that isn't how maps were done, but I like the idea of it having a bit more tactility than ink.

Don't use the swivel knife. Just bevel the lines or use a modeling spoon. 

[hotleatherworlds]

I would never apply petroleum product on leather as it can damage my natural leather but instead use a high quality leather conditioner or specific product. 

[TomE]

54 minutes ago, hotleatherworlds said:

I would never apply petroleum product on leather as it can damage my natural leather but instead use a high quality leather conditioner or specific product. 

I would agree about avoiding petroleum products for my work.  As a point of information Al and Ann Stohlman mention in their Encyclopedia of Saddle Making that they used a lot of neatsfoot compound (mix of neatsfoot oil and petroleum based oils) without any bad effects, recognizing that pure neatsfoot oil is best but expensive.  Leather is exposed to a whole lot of unnatural chemicals during the tanning and currying processes, so for me it's more about chemistry than nature. 

Here's an old monograph on the chemistry of leather.  I don't think the process has changed much in 70 yrs.

Phillips-1954-THE CHEMISTRY OF LEATHER.pdf