A headstock vs B headstock

[JPG]

As an aid to those lacking in 'historical' knowledge of early headstock versions I submit the following:

The earlier "A" headstock was a sand casting and is both heavier(thicker wall etc.) and rougher.

In the pix below the "A" is on the left and the "B" is to the right.

A B HEADSTOCK REAR.jpg (597.51 KiB) Viewed 7845 times

Starting at the rear, notice the lack of a tapped hole at the top of the idler shaft hole.

Notice the heavier different shaped lower web bridge.

Notice the larger size of the idler shaft eccentric clamping ears and the flash surrounding them.

A B HEADSTOCK FRONT SIDE.jpg (448.65 KiB) Viewed 7848 times

Moving to the 'operator' side there are several differences.

The most obvious one is the shape of the speed control mounting hole.

Notice the power switch mounting area. The "B" is recessed.

The "A" has the top of the speed control 'circle' cut away. The "A" used a push plate to provide a 'stop' at saw-joint speed. The plate must be depressed to increase the speed higher. That is the reason for the 'groove' on the back of the indicator dial. The "B" added the small 'anti-rattle' spring which gives slight tactile feedback when increasing the speed past that point.

Notice the larger bosses at the quill shaft and lock bores.

Notice the belt cover attachment screws are tapped directly into the "A" and a seat for a tinnerman clip on the "B".

Also notice an additional belt cover mounting screw. There are 8 screws on the "A", but only 2 on the "B".

Finally the "B" has two areas 'cut away' in the drive belt area.


[ATTACH]14437[/ATTACH]

A B HEADSTOCK BACK SIDE.jpg (478.64 KiB) Viewed 7841 times

The most obvious thing on the back side is the access hole in the "B" where the medallion mounts.

Again the bosses are larger, and the belt cover screws etc.

The cutaway areas again differ.

The recess under the quill stop etc. is more sloped on the "B".

[ATTACH]14438[/ATTACH]

A B HEADSTOCK FRONT.jpg (598.99 KiB) Viewed 7842 times

Not much differing on the front, but the width of the raised (seam?).

The top 'seam' is also wider on the "A".

[JPG]

[attach]14439[/attach]

The wide seam(?) continues across the top of the "A"and the quill anti-rotation half dog screw hole has a wide round boss around it on the "B".

Again the cutaway areas on the "B".

As a side point of interest, notice the retaining ring in the "B" at the front of the main bearing bore. This ring is the same as the one retaining the back end. The "A" has a pair also, but none in the pix.


[attach]14440[/attach]

Finally the inside, bottom has similar differences.

Yes those are spider cocoons. These are stored outside at present.

[wiredone]

Thanks for that history lesson, I do so loves me some history!
Because of the heavier casting on the A models would they tend to vibrate less?

[JPG]

Thanks for that history lesson, I do so loves me some history!
Because of the heavier casting on the A models would they tend to vibrate less?

I think they 'resonate' less!;)

[wiredone]

Resonate is a much better description, thanks.

[charlese]

Thanks, Red! Always wondered; just what are all the differences.

[idcook]

Thanks GG (JPG),

That was a great eye-opener. Definitely a thread I'll study until it becomes ready knowledge that I recall before making any future purchases.

[joedw00]

Thanks JPG had wondered what the difference was.

[jamescaxton]

I do so loves me some history!

[everettdavis]

[attach]14439[/attach]

The wide seam(?) continues across the top of the "A"and the quill anti-rotation half dog screw hole has a wide round boss around it on the "B".

Again the cutaway areas on the "B".

As a side point of interest, notice the retaining ring in the "B" at the front of the main bearing bore. This ring is the same as the one retaining the back end. The "A" has a pair also, but none in the pix.


[attach]14440[/attach]

Finally the inside, bottom has similar differences.

Yes those are spider cocoons. These are stored outside at present.

I have an 'A' Series Headstock, with no top seam at all. Have you ever seen one without any seam on top other than this one?

Early A Series Headstock with no Top Seam.jpg (519 KiB) Viewed 7218 times