48 or 52 or 54" What Length to Chose for the Next Featherweight Camelback?

48 or 52 or 54" What Length to Choose for the Next Featherweight Camelback?

I was recently contacted by a PM member concerning my next Foster Featherweight Camelback which exists only as a line drawing at this time. I had arbitrarily chosen 48" as its proposed length. But he suggested that a 52 or 54 might be a bit more useful and could still be scraped on a 36 X 48" granite surface plate. He noted that currently available SE's over 36" tend to be quite heavy and one that could reach under doves, be lightweight, and 50+ inches might be a very useful design. I think that using a design quite similar to my 36 but scaled up a bit could maintain its excellent rigidity and could weigh well under 40 pounds. The Featherweight 36 comes in around 22 pounds if liberal material is left in machining and come in at 19 pounds if it is desired to trim it down in weight. So getting the 48-54 to weigh mid-30's should not be difficult.

So, I'd like to hear folks opinion on this to help guide me in making the next lightweight design.

Denis

dgfoster said:

I was recently contacted by a PM member concerning my next Foster Featherweight Camelback which exists only as a line drawing at this time. I had arbitrarily chosen 48" as its proposed length. But he suggested that a 52 or 54 might be a bit more useful and could still be scraped on a 36 X 48" granite surface plate. He noted that currently available SE's over 36" tend to be quite heavy and one that could reach under doves, be lightweight, and 50+ inches might be a very useful design. I think that using a design quite similar to my 36 but scaled up a bit could maintain its excellent rigidity and could weigh well under 40 pounds. The Featherweight 36 comes in around 22 pounds if liberal material is left in machining and come in at 19 pounds if it is desired to trim it down in weight. So getting the 48-54 to weigh mid-30's should not be difficult.

So, I'd like to hear folks opinion on this to help guide me in making the next lightweight design.

Denis

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Not a huge advantage between 4ft & 4ft 6 - but I would go for the 4ft as its likely going to be less trouble making it and scraping it in a 3ftx4ft plate is easier than trying to squeeze 54" corner to corner with every part of the plate error affecting the scrape. Just my two pennies worth & Im no expert.

Might be worth checking what length Dovetails folks are trying to print - bridgeport column & tables are going to be common projects I would suspect & a longer SE for single print would come into its own - but that brings with it its own issues of scraping the SE in to start with. A 4ft SE scraped in on a 3x4 plate can be easily step printed on a a 54" way.

The other option would be light weight 6ft but thats a whole new challenge.

I used my slim 54" SE to print all the ways on my lathe - it was 6" shorter than required but far more user friendly than the 75lb 6ft SE (the light one) - as I say, Im no expert - but from choice - I would go with a SE I was 100% happy with and a bit short than a longer one I suspected.

Mat

I'd stick with common sizes as there's always going to be a job that makes the SE in your hands 1" shorter than you'd like, so you have to work around it until you get a bigger SE.

But by the same token, any extra length is a plus.

I appreciate your and Lurk's thoughts. That is why I put this question up for discussion in order to see if there is a consensus as to whether a "standard" length vs a little longer might offer significant advantages. Still listening....

Denis

I'm the person who was talking with Denis offline about his next FeatherWeight. I intentionaly didn't post until now to allow others to speak first.

As I see it, and as a relative new comer to scraping, there's a bunch of 48" SE's available both new cast and old. I did scrape in one of Richard's 48" dovetails and use it regularly. It weighs mid 60 lbs. Other than weight, it works well.

If Denis is to make another SE design, I'd suggest it be not only lightweight, but also different length than most currently available castings. I don't find my 48" SE as easy to use on a 10x50 turret mill table just to mention one example. Yes, it can work, but a slightly longer than the table SE would be better. In North America, I've seen plenty of 48" and 60" SE available on used market, thus my suggestion to Denis of 54" length and maybe 9" camelback height. Bonus is ease of scraping it in on the commonly used 48" x 30" or 36" surface plates. The only 54" SE with dovetail casting that I'm aware of recently available is the roughly 120 lb casting Gary Martin made. Knowing Denis, and his meticulous attention to details, I'm sure his would be substantially lighter.

Really, any new design should be whatever Denis finds most useful for his own projects. I'm just trying to gently nudge him into not only a unique light weight design but different length than the others.

Lucky7

Hi Denis,

I remember reading about a old-time shop back East that used only
30" SEs, and they weren't camel backs. In the article they were scraping
a very large SIP jig borer. The SEs were just prisms. The article was
in an Machinist rag, and I don't remember the name, but I still may have a copy.

Richard King referenced this article in one of his posts.

The point is that you don't need a big SE to get the job
done, but it just makes the job easier.

The old guy doing some of the scraping was in his 70s.

Paul Hoffman

Please teach me how to scrape in a large jig borer using just a prism.

Lucky7