What Exactly Is A "split" Ebonite Feed?

[macball]

I recently acquired a 1970's era MB 146 in very good shape except that the piston was stiff. I took the piston assembly apart to lubricated it with silicon grease and discovered that at some time in its history there was a leak of permanent black ink behind the piston. The plastic piston sleeve and screw cleaned up fairly easily but the brass part required a lot of elbow grease and Brasso using a tooth brush to bring it back to gleaming. I have been using it for the past few days and there is no indication after lubricating the piston that there are any leaks. On the other end of the pen I found it to be a bit dry. I examined it under a high power microscope and used the thumbnail trick to bend the tines up a very small amount. I also noticed that the tines were a bit misaligned which is why it was a bit scratchy. This is not something I noticed even using a jewellers loupe. But in the process examining the nib and aligning the tip I noticed that the end of the feed was moving. Oh oh! A cracked "Ebonite Split" feed. You will notice that the ebonite feeds have a groove that runs horizontally across the sloped smooth part of the feed near the end. On some ebonite feeds I noticed that it is not even cut straight. The crack ran from this groove straight back again. I thought that it was strange that the end of the feed didn't fall off. But in this case the crack extended backwards into the body of the feed and the end of the feed beyond the groove was attached by apparently one or more central internal parts that had not broken. The part beyond the groove was quite flexible and I could see it bobbing up and down as you applied pressure to the nib. I thought if I send it to MB they will remove the ebonite feed and replace it with a modern plastic one. Would I be able to find a vintage ebonite feed and replace it myself? The split seemed to be very fine so maybe I could stabilize the crack with something like superglue. Something is very strange about this split in the feed. It seems very precise and runs perfectly back into the feed. The end of the feed seems like it is suspended by an internal part of the feed. Then it dawned on me!! Is this SUPPOSED to be like this? Is that why they call this early ebonite feed a "Split Ebonite Feed"? Because it has a split in it? I thought any split was part of the internal mechanism.

[meiers]

Your post is intriguing. Could you share a photo of this feed?

Edited May 28, 2015 by meiers

[zaddick]

Yes, this is intended and, to my knowledge, what is meant by split ebonite feed. Pictures would help to be sure I understand what you are describing.

 

You can get replacements from penboard.de and probably other sources. That one is just well known to me. MB will replace it with plastic.

[jsolares]

Both of these are from 146,

 

solid ebonite feed

split ebonite feed http://vacumania.com/penteech2/MB146feed.jpg

 

Or you can see them in the 149 dating chart

http://i573.photobucket.com/albums/ss171/DKbRS/Pens/MB149Dating-2.jpg

[CS388]

I'd say "Yes, it's supposed to be like this" - but it would have to be a guess, without seeing photos?

 

My 146 of the same era had a split ebonite feed. I still have it (the SE feed), if you need a replacement. It has one broken fin, which doesn't affect perfomance.

 

I had to swap it out as I replaced the feeder case with a more modern variant and the dimensions are different (Modern is larger). The difference is only slight, but sufficient to mean that the SE feed was too small for the new case, so I had to go with the plastic feed, which was supplied with the feeder case.

 

Good luck.

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146feedfingone.jpg

 

The feed I mentioned. If you look closely, you can see the 'split' running along the feed.

Still got it. Free, if you want it.

[AndrewC]

"It's a feature, not a bug!" Yes,it is supposed to do that. The idea is that if you flex the nib the feed stays in contact with the nib and you do not lose ink flow. FWIW, I do not think you could "repair" it with SuperGlue as the feeds are made from ebonite (rubber), and they are porous. Split feeds are considered a desirable item by many. I know I am very fond of the one on my 146. It never lets the ink flow drop, even when I am writing at speed and geting flex out of the nib.

Edited May 29, 2015 by AndrewC

[StrawberryJam]

Or you can see them in the 149 dating chart

 

 

What an amazing resource! Does this chart also apply to the 146?

[macball]

Thanks! No, I won't be "fixing" it with superglue or replacing it now that I know it is not cracked. As you can see from the two pictures posted by Jsolares above, the two feeds look the same except for that horizontal groove near the end of the feed. Even on close inspection it simply looks like a groove. However, if you look carefully at the side picture posted by CS388 you can see a very fine "crack" or SPLIT extending from the groove backwards. There is another one on the other side. As described above, the end of the feed in front of the groove is only connected to the back part of the feed by one or two narrow arms or levers that are inside the feed so that the end of the feed "floats" under the tines of the nib. The split is extremely fine so that it is nearly invisible. How did they cut such a thing? Under high magnification the movement of this mechanism is amazing. I was shocked. There is actually quite a bit of movement and I could see that a nib with this feed would theoretically be more flexible because the underlying feed is set on a spring. There is nothing for me to photograph on my nib feed that isn't shown in the photos above. What would be informative is a high magnification movie of the movement of the split ebonite feed when writing.

 

I can now see why MB abandoned the split ebonite feed in favour of the plastic one because of expense. I assumed that was because of the cost of "precious ebonite", but the manufacture of this complicated device must have been the reason. It is a feat of engineering and manufacture. If you haven't had the opportunity to carefully examine one of these it is well worth it!

[delano]

The idea is that if you flex the nib the feed stays in contact with the nib and you do not lose ink flow.

 

 

 

Obviously, this idea didn't work, or we'd be seeing more of these in use today. Any idea as to rarity?

[FredRydr]

Or perhaps the split feature of the ebonite feed cannot be duplicated in injection-molded plastic at an acceptable cost.

 

Fred

Edited May 29, 2015 by FredRydr

[meiers]

Well... I am offering a 146 with a split

Ebonite feed in the classifieds and am now having second thoughts about selling it. Thank you Macball for starting this conversation. I think I will keep that 146.

Edited May 29, 2015 by meiers

[meiers]

 

 

Obviously, this idea didn't work, or we'd be seeing more of these in use today. Any idea as to rarity?

I think that idea did work.

[talkinghead]

Both of these are from 146,

 

solid ebonite feed

 

 

That pen and picture looks familiar!!

 

 

 

What an amazing resource! Does this chart also apply to the 146?

 

You can extrapolate some information from the 149 chart and apply to the 146, though mainly the celluloid 50's pens and then again from mid 70's and on. There was no regular production of 146 during the 60's and it was reintroduced in '73-'74 with a very short production of solid ebonite feeds that are much less common on a 146. The split ebonite feed is the typical feed you will find on most late 70's and 80's 146 before they changed to the plastic feeds. Nibs though, are totally different in appearance through the years as compared to the #149.

 

Rick

[jsolares]

 

That pen and picture looks familiar!!

 

 

 

You can extrapolate some information from the 149 chart and apply to the 146, though mainly the celluloid 50's pens and then again from mid 70's and on. There was no regular production of 146 during the 60's and it was reintroduced in '73-'74 with a very short production of solid ebonite feeds that are much less common on a 146. The split ebonite feed is the typical feed you will find on most late 70's and 80's 146 before they changed to the plastic feeds. Nibs though, are totally different in appearance through the years as compared to the #149.

 

Rick

 

I blame google , funny now i'm looking at google to see where i got it from and link the post and it's nowhere to be found... I hope you don't mind

 

 

 

Obviously, this idea didn't work, or we'd be seeing more of these in use today. Any idea as to rarity?

 

Considering that it's the feed that was second longest in service on the 149 only second to the current plastic feed, I'd say it worked just fine. besides they've moved to more stiff nibs so no longer a need for the design.