Just so it’s said. The Preston- and Tyzack-style router plane is not worth any more than any Stanley or Record type and not worth as much as the Veritas or the Lie Nielsen router planes. Just saying, that’s all! They do no more than the others and in most cases they don’t actually do as well. The only, only reason I liked mine from the beginning was that they were unusual, but not at all any better. I have sort of collected them, but my first one cost me about £10 via eBay. I liked the price more than the plane. Soon they will all be gone from the net unless a collector or collector /user wants to sell theirs on.
Whereas it does have a feature or two for inboard and outboard functionality, I have not used this in anything I have made nor have I found the more common routers less advantaged. I say all of this because I hate that anyone should taker my usage as some sort of endorsement when all I want is people to pay a fair price. Whereas the regular routers by Record and Stanley have gone up and up in price, they have also levelled off at a fair price that’s not prohibitive to those willing to save for them.Some do complain that £100 or so is a high price for their budget, but most people will eat out and spend the price of a plane in half a dozen coffees and two or three meals out. When I bought my hand tools most of them cost me a week’s wage. It wasn’t too much with 55 years in the using of them 6 days a week. .00104895 of a penny a week.
The hump in front of the cutting iron is well worth having even if you negate its functionality by adding the wooden sole. It’s this feature alone that betters the Preston-style version really. Of course putting the cutting iron outboard as shown enables you to plane into a stopped housing dado and all of the router planes have this feature anyway.