I had a good look at the bike's various characteristics and the serial number and I can't match it to any known Dutch builder. There are some things that do not match:

Theorem 1: the bike is a Dutch-built export bike:
This is supported by the decal on the seat tube. Moreover, I have seen the head badge before, in the collection of a major head badge collector, and he had identified it as having a typical Dutch style. This bike supports this.

It is also supported by the '59 date code on the SA hub. The Dutch export to the US grew from just 14 bicycles in 1950 to 36,000 in 1955 and 75,000 in 1957. Around 1960 the export collapsed, apparently because other exporting countries became cheaper.

Theorem 2: the bike was not built in Holland:
This is supported by the characteristics of the bike in combination with the supposed 1959 build year. Dutch bikes did have serial numbers on the left rear dropout, but those were usually track style dropouts, to be used with chain tensioners. Only Magneet, Locomotief and Joco made 'super sport bikes' with derailers and front-facing dropouts, in very limited numbers. This Crusader is a different type of bike. Also, you would not find riveted dropouts on a super sport bike. I only remember seeing this on Locomotief bikes from around 1940, but it is not something I usually pay much attention to. At that time the BSA bottom bracket shells usually had two tension bolts on the underside.

I've only seen the Crusader's head tube lugs on Magneet bikes from the 1950's, but Magneet used a different fork crown. Anyway, I've never seen this particular big and plain fork crown on Dutch sports bikes from that era.
I've also never seen the strange braze-on on the left seat stay. I don't see the relation to drum brakes, like the owner suggests.

Regarding the serial number: I see 8278 and in front of that a 'lowered' letter, possibly an 'S'. Two brands carried serial numbers with that format durin tha late 1950's: Germaan and Batavus. Batavus may have been exporting, but Germaan is less likely. Another large manufacturer, Hartog from Zeist, did export a lot to Indonesia and the US, but hardly sold anything in Holland, so is not well known here. The only Hartog I know of (in the US) looks different.

Conslusion: I think it is a Dutch export bike, and the 1959 year is likely as well. But I doubt it was actually 'Made in Holland'. If so it must be a model specifically aimed at US tastes in style. Not uncommon as far as the choice of components was concerned, but I know of no specific 'US model' frames. It may have been bought elsewhere and exported through the Dutch manufacturer. Who that was is still unclear.

Another small, but not insignificant detail I just noticed: the lock says 'Magneet' and has the Magneet logo. That is significant, as the lock being a later addition is highly unlikely.



Magneet serial numbers were made up of a number, followed by a space or hyphen, in turn followed by four numbers. See the example below.

The head tube lugs are similar, like I said. See the comparison picture. The lower head set cup matches, and both bikes sport a Weinmann Junior front brake as well. The fork does not match (it may have been a US-specific item) and neither do the rear dropouts.



Nevertheless: it could well be a Magneet export bike.