Thread: How to mark a mortise on rough surface?

Maybe you could stick some tape on the timber, mark with pen then use chisel to cut through tape and mark timber? Not sure what you aim to build but keep in mind that you need to be able to clean all surfaces in kitchen pretty thoroughly so these rough surfaces may be a challenge. Give us some more detail on bench top material, planned finish and planned use and more ideas will flow. Cheers

Sorry Farmer Geoff I obviously wasn't very clear in my description. I have a 1m leftover piece of oak benchtop that was an off cut when I installed the kitchen. I will apply a food grade oil and use it as a chopping board/butchers block. I plan on using the recycled fence posts as the base frame for the island. I want the use mortise and tenon joints but was wondering if making accurate markings on the rough surface was possible or it won't really matter as ill have to make final fitting adjustments for a tight fit?
here is a photo of the top that ill be using. I also plan on putting in a couple of drawers.

Originally Posted by Njmpm

..... Any idea what type of wood the posts are?.....

Nick, there is not a remote chance of id'ing that wood in the rough, and only marginally more if it were cleaned up. If they are ex posts, they are most likely a eucalypt, which narrows you down to a couple of hundred possibilities. If they were cut locally, what's the most common species used in your locality? If they were brought from somewhere else, it's anyone's guess.....

Originally Posted by Njmpm

.....how would I make an accurate mortise mark? I don't have a mortise gauge yet but will be purchasing one. Will the mortise gauge wander when going over all the rough wood and if there is a tendency for this to happen is there a secret woodworkers trick you could tell me so that ill avoid this rookie error?

It's not really a secret. The easiest way to use a marking gauge is to rest the beam on the wood, roll it 'til the points make contact, then push it away with the points dragging. You control the depth of the marks by how much downward pressure you apply to the points - it's better to make several light passes on rough stock like yours, as you are less likely to get wandering. Pushing the stock ('fence') firmly against the work is a must. Don't try to mark with the points held vertically, or near-vertically, as this increases the risk of the points going off-track. Pick the best sides of the posts & rails (i.e. straightest & cleanest) to mark from, as this will give you the most accuracy. By using marking gauges & working from 'show' sides, you should get pretty good accuracy, then it comes down to how neatly you can chop out the mortises & cut your tenons...

Cheers,

Thanks Ian much appreciated
I think ill practice some mortise and tenon joints on some scrap before doing these.