Rubbing in with arthritis

Nowadays I usually use a basic food processor to do the rubbing-in.

Melt the fat and stir into the flour ?

You can buy a metal tool, called a pastry blender or pastry cutter. Various places sell them, one example
www.lakeland.co.uk/33723/tala-pastry-blender?utm_source=google&utm_medium=cpc&gad_source=1&gad_campaignid=20891625552&gbraid=0AAAAADtoD6OjFv5HLQBore7wA4U6MhYc0&gclid=CjwKCAjw-8vPBhBbEiwAoA39WpPRzgEYG8bigLiqEGDAq6AfrUVlv02oAMG6s_aS8YejKHSMrcPWKhoCh_AQAvD_BwE

Use a cheese grater if you can.
It is like breadcrumbs without rubbing in.
The fat has to be very firm of course, half an hour in the freezer will do it.

I use my blender for rubbing in, particularly for making crumble topping and pastry.

If you use vegetarian suet it comes in small granules so easy to mix in. Ok not suitable for all recipes but thought I would mention.

I put the ingredients in the food processor. In fact, I often weigh out flour and fat, blend it in batches and freeze at the ‘breadcrumb stage’ ……… that way the food processor is used for more than one recipe and saves on washing up.