Wooden Garden tool homemade formula
Thank you for using Ask an Expert for help keeping your garden tools in good shape. I have not found a formula that includes all of the ingredients you list, but several that mention them individually.
An Oregon Extension publication from 1970 suggests ¾ boiled linseed oil and ¼ gum turpentine as a cleanser-conditioner. For the publication and full directions, see page 5 of Furniture Restoration. Download it here: https://ir.library.oregonstate.edu/downloads/02870v94c
There are several other Extension Service publications of similar vintage, using linseed oil and lemon oil, just lemon oil, just linseed oil, and varying proportions of the ingredients. Your speaker may have begun with one of these recipes and then experimented to find his/her own favorite.
Most modern recommendations suggest the use of linseed oil alone. See here: https://extension.oregonstate.edu/news/take-one-more-go-garden-retiring-winter and here: https://aces.illinois.edu/news/garden-tool-care
Keeping tools in good shape will make them last longer and be safer to use. Congratulations for your efforts.