Macomber pulls weaving apart

I have a problem.  I had thought it was me, but did an experiment and now I'm pretty sure it's not me, it's the loom.

The experiment was to weave the same pattern, same fiber, same sett on both my 8H Mac & my 8H Varpa, with a purpose of deciding which loom to sell.  Since each loom has some real benefits, this is a tough choice I have to make.

I wove with 8/2 rayon in a pinwheel pattern.  Sett at 18 EPI on both looms.  Although I tried to make them the same, if anything the tension was tighter on the Varpa than on the Mac.  I had the same problem on the Mac that I've had before...the weaving is fine on the top of the loom, but weft threads separates, I think as it goes over the breast beam.  I had thought that I may be causing the problem by having my stomach brush the front beam, so this time I was very careful NOT to do that.  But here are two pix to demonstrate what I mean.  The first photo is the cloth before it goes around the breast beam.

Weaving over the breast beam

In the second I'm spreading the warp apart with my fingers so that you can see the weft threads underneath.  The red lines point to where the weft has pulled apart in 2 pattern repeats and crammed in another.

weaving after it passes the breast beam

So all you Mac users, is this a typical problem that can be easily resolved?  If so, what's the fix?  If not, I guess the problem with weaving quality will make my decision on which loom has to go -- because this fiber, this weight, this sett is fairly typical for me, it'll have to be the Mac.

Thanks for your insights.

Comments

Posted on Sat, 09/01/2012 - 18:50

18 epi for 8/2 rayon may be too loose a set.  Then your weft has to be spaced to square out the design and that can cause the weft to shift.  Have you tried re-denting at 20-24 epi?  See if that resolves the issue.  Pinwheels need a more = ppi/epi.

Dawn

 

Posted on Sat, 09/01/2012 - 21:47

That would make sense, Dawn, except that I used 18epi/ppi on the Varpa with no problem.  I use 18epi/ppi with this yarn on my 4H counterbalance for various weave patterns with no problem.

Posted on Sat, 09/01/2012 - 22:24

The one thing I notice in the second photograph is the appearance of irregular beat -- the pinwheels do not appear to be the same size.  Is this the same area of cloth that was shown in the upper photo? 

I have not experienced such a phenomenon on my Macomber.  Although I weave both finer & heavier, I have not used rayon.  I do use a lot of bamboo, though, as warp and weft.  I usually use denser setts and heavier beats.

Is the breast beam more curved on the Varpa? 

It would be worth while to mark the exact row that sits on the the edge of the breast beam towards you each time you advance the warp (like with a stitch of red yarn through the selvage at the exact row).  That way you could test your theory about it being beam related

Posted on Sat, 09/01/2012 - 22:45

Yes, I have had this problem.especially in light setts.  I wove some very sheer silk scarves and when it happened I padded my beam with something that would still go around the beam when the cloth moved.  However, I have decided that the best fix is to round the edges of the beam.  There is a slight break in the wood and when the cloth goes around, it causes the seperation.  I think if you want to weave looser setts, you should have that choice.

As a side note my old Newcomb had a perfectly round beam and I never had this problem, and I wove linen transparencies on it.  This is the reason I think smoothing that edge would work.  We just haven't got around to doing it.

Cheryl

Posted on Sat, 09/01/2012 - 23:09

That makes sense, Cheryl.  Thanks for the suggestion.  What did you use for padding?

I'm trying to decide if I'll sell the Varpa or the Mac - I don't have room for both.  I know if I keep the Varpa I have some mods to do.  I guess I do to the Mac, too.  I'm not a woodworker -- I wonder if I can get someone to remove the breast beam and round it.

Posted on Sat, 09/01/2012 - 23:16

I thought about this a lot a few years ago.  A Cranbrook loom I once used had a round steel pipe for the breast beam.  I've often thought I could get a length of PVC pipe to slide over the rectangluar breast beam of my Herald loom if weft separation becomes a problem. (The beam is easily removed.)

Posted on Sat, 09/01/2012 - 23:19

The fabric I used was a slippery probably polyester blouse fabric from my stash! I was looking for something that would slide easily.

My woodworking husband doesn't think it would take much to break that edge, just sand paper.  You could start with a coarser grit and then smooth it with a finer grit and then oil if necessary.

He can advise in more detail if you go that route-just ask.

Cheryl

Posted on Sun, 09/02/2012 - 01:17

I'm wondering if the leg from an old nylon panty hose would work.   You'd have to remove the beam (it's screwed on on my Macomber) to slip the stocking on.   And you'd want to cut the toe off to slide it onto the beam.  That should just roll with your fabric    I hear cowboys wear them under their jeans to prevent saddle sores.

 

Posted on Sun, 09/02/2012 - 01:44

The pantyhose is an interesting idea.  I'm planning to ask a woodworker friend to round off my beam - or to replace it with a round beam and I'll save the original for the next owner...whenever that may be.

Peg

Posted on Sun, 09/02/2012 - 13:56

When Macomber makes the beams they use what is called a rounding over bit. The problem is sometimes were it goes from round to flat there is a line and not a smooth trancesion. You can remove this line with a "nail" file, a real file or sand paper. I would do both the top and bottom of the beam.

Michael

Posted on Sun, 09/02/2012 - 11:35

That's all it takes is a bit of sanding?!  I hadn't noticed that 'line' till you pointed it out, Michael.  So I got 80, then 150, then 240 and sanded the breast beam.  I can definitely feel the difference.  

Now do I need to finish it with something?  If I just oil it, will the oil come out on my fabric?

I just put a warp on my little counterbalance, but I'll do a short warp on the Mac as soon as I'm done...and you tell me what to finish the beam with.

THANKS!!!

Posted on Sun, 09/02/2012 - 14:13

I guess we will find out if this will do the trick. I would finish the beam with Danish Oil, it comes in natural or different wood tone colors. You rub in on, I use a 400 or 600 grit wet/dry sand paper, this will make the finish as smooth as glass. Wipe off any excess and let dry 24 hours. This finish has plastic  polymerizers in it and will dry hard. After 24 hours I would lightly sand with your 600 paper and after wiping off you should be ready to go.

Everyone will be waiting to hear if this fixed your problem.

Michael

Posted on Sun, 09/02/2012 - 14:58

I'll have to wait till I can get to the store to get the Danish Oil and appropraite sandpaper, but I'll sure give it a shot, Michael.

Posted on Tue, 09/04/2012 - 04:51

In Southeast Asia the fix of choice on spme of the rough back beams is wrapping newspaper around the beam and adding a layer of saranwrap. Not what the silk grandmothers would have done but works great with the fine silk warp.

Posted on Tue, 09/04/2012 - 20:04

My colleague at the university was weaving very openly in wools of different weights as samples for later work with fullling of some areas. She avoided the beam potential problem by adding a PVC pipe over the beam, making it round. I'll ask her just how she did it but recall that it worked just fine.
Tommye

Posted on Tue, 09/04/2012 - 23:10

I love everything from the low-tech/no-cost newspaper & saran wrap to the Glimakra aluminum beam protectors.  I just picked up the sandpaper & Danish Oil today, so I'll give that a shot later this week when I have a few minutes - and hopefully it won't be pouring so drying will be better.

Posted on Thu, 09/06/2012 - 23:06

Today I did the 400 grit sandpaper & oil.  Friday or Saturday afternoon I'll use the 600 grit sandpaper, and maybe I can get a warp on it before the weekend's out to test it out.

I'll keep you posted!

Posted on Fri, 09/07/2012 - 22:26

Peg,

I had that exact kind of weft separation problem and originally thought it was due to the breast beam as well.  I found it quite frustrating until I finally figured out the problem.  I'm a little embarassed to tell you what caused it.  In my case it was caused by the lower edge of the shuttle race on the beater contacting the finished cloth below the breast beam when beating and messing up the weft.  It doesn't take much contact to leave gaps in the weft.  This happens when I advance the warp too far, causing the fell line to fall too close to the breast beam. Try keeping the fell line a little closer to the reed where the unwoven warp and the cloth are farther apart and see if that doesn't solve the problem. 

Posted on Fri, 09/07/2012 - 22:35

I'd not paid attention to that, mrdubyah.  Knowing me, I can imagine that I may well advance that warp too far.  I will definitely pay attention for the warp I'm going to put on that loom this very evening (I hope).  Thanks for one more clue!

Posted on Sat, 09/08/2012 - 14:36

I just acquired a really old 40" Macomber (#61...sold in March 1940).  It is absolutely beautiful and in great condition, made of oak.  I am busy cleaning it up and swapping out parts to make it more user friendly (a couple of years ago I had bought a 40" Macomber that I ended up using for parts and now I'm so happy I did!).  The cloth beam is squared off.  Has anyone seen this before?  Will it cause a problem with separation on the finished cloth?

Posted on Sat, 09/08/2012 - 15:08

I have 8 Macombers and this weft pushing will happen if you bring the fell line up to close to the breast beam when advancing, causing the lower beater bar to make a 'pushing motion' contact with the lower fabric...I can create this slipping weft situation on cue! Just don't advance too far, learn each loom and what it needs and notice when to stop advancing and start tighting for weaving withOUT bring the fell line too close to the front! Happy weaving!!!

Posted on Mon, 09/10/2012 - 14:35

Ok, so I have a warp on my Mac, have woven several inches, and here's what I found.  Mrdubyah is correct.  The bottom of my beater bar absolutely rubs agains the finished cloth after it has gone over the breast beam.  

So I loosened the tension on the warp, lifted the beater up off the pegs, got under the loom and adjust the cast pieces so they we 'up' instead of 'down'.  (Should have taken a photo, but didn't.)  Put the beater back on. 

Nope.  That's no good - there is absolutely no shed at all.  Release the tension, lift the beater bar, go back under the loom and put the cast pieces back into the down position.  Put the beater back on the pegs, but instead of in the lowest position -- the longest slot in the bottom of the beater bar (which is where I've always had it) -- I put it in the middle slot.  

Now my shed is clear, but small.  And still, in order avoid completely the bottom of the beater from hitting the fabric, the reed cannot come closer than 4" from the back of the breast beam.  That's quite far away.  

So I'm wondering what other Mac owners have done to (a) avoid the problem of breast beam hitting the cloth, (b) get a large shed, and (c) have a decent weaving depth (perhaps not the correct term -- what I mean is number of inches that can be woven before the warp is advanced).

Perhaps I should post this question to the Mac group??

Thanks for your thoughtful responses!

Peg

EDIT: My shed is ok.  I had put some 2" 'bumpers' on the beam to bring the beater at rest closer for my short arms.  When I removed those bumpers, the shed is just fine, as is the weaving depth.  

Has anyone put a 'bumper' of some type on the back of the breast beam to help ensure that the beater can't get too close to it?

Posted on Mon, 09/10/2012 - 15:19

Peg, I haven't used a bumper on the breast beam but you might try something like folded wash cloths that you tie into place to see if something that acts as a stop point there might work.  If those seem to help then a more permanent solution might be found by wandering through the hardware store looking for rubber or foam pieces of some sort.  Another thought would be to cut foam core board to the size of the beam and layer several together until the right depth is achieved.  Those could then be attached to the beam with double-sided tape.

Just a few thoughts.

Tommye