Build Your Own Needle Puller, Part Two

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keithstout
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Build Your Own Needle Puller, Part Two

#1 Post by keithstout » Sun May 24, 2020 1:17 am

Build Your Own Needle Puller, Part Two

The duo has now been brought close to the loaded capillary. This shows that the shaft, capillary, and drop collar slot are all in alignment:
bottom tube aligned.JPG
bottom tube aligned.JPG (90.56 KiB) Viewed 1823 times
The capillary is loaded into the drop collar the same way it was loaded into the top spacer. I made strips of paper of specific widths, measured in mm, to set the drop stop at specific distances from the drop collar. With the drop stop positioned for a pull, the drop collar is now suspended by the capillary alone.
bottom tube installed.JPG
bottom tube installed.JPG (90.38 KiB) Viewed 1823 times
Here is an overview of the loaded capillary, which is now ready for a pull. Notice how it nicely parallels the shaft. If I apply heat to the center of the capillary, the glass will melt, permitting the drop collar to drop and pull the needle. Read more information below this final image.
whole assembly.JPG
whole assembly.JPG (91.91 KiB) Viewed 1823 times

It is best if the components of the puller are manufactured with precision. Play in the drop collar can make crooked needles. The shaft should not be lubricated. Lubricants have viscosity and will cause variability in pull speeds. Clean the shaft with denatured alcohol or acetone. Be sure the drop collar slides freely along the shaft before attempting a pull.

The pulling force and speed of the drop collar can be increased by adding flat washers on top of it. With my puller, the drop collar seems to be of acceptable mass and currently needs no adjustment.

My hands are free to work and make the first pull. I set the drop collar for a 5mm pull. I heat the capillary center with a small butane torch. I move the torch around the capillary's circumference for more even heating, using quick movement. The glass melts and forms the taper in the first pull. Careful glass heating technique will produce a symmetrical taper. I set the drop stop at about 3mm for the second pull, which will form the needle and, hopefully, separate the capillary into two needles. My heat application changes for this step. I heat the center of the newly formed taper by flicking the flame to and from it with very snappy pivots of the torch body. The fine taper requires less heat. If the capillary does not separate, a third pull is required, using even less heat. Patience and practice with heat application are needed for consistency in needle quality, but this can be learned. With my first six test pulls, I produced 4 usable needles and broke a fifth. Before I knew it, I had a stable of 31 needles. I had such a marvelous time pulling that I lost count.

By manipulating pull length, pull force/speed, and heat, you can easily make different kinds of needles for moving different diatoms. One might want a finer needle for smaller diatoms, for example. One might want a stocky needle to root around grot deposits. Careful notes will help the operator quickly set up his puller to produce different needle types.

Do not pull needles in strong air currents as that produced by swamp coolers. This interferes with the heating of the capillary tube.

The total cost of my mousetrap was $10 for the torch. I had everything else. Another benefit is that the shaft can quickly be pulled out of its hole for compact implement storage.

I hope this encourages some beginners to try needle pulling. It can be fun. I really enjoy the diatom discussions. Questions are always welcome. Let me express very special thanks to Kurt Maurer. Talk about a man with his heart in the right place! He's done so much to cultivate my study of diatom herding. I only seriously considered attempting the task in Dec. '19. I'm already comfortable with moving diatoms to a clean slide. If that wasn't enough, he re-sized my images in this post to fit the MH posting protocol, this amidst a busy busy time for him. Because of him, we can all benefit from these contents. Thank you so much, Kurt.
Keith Stout
Last edited by keithstout on Mon Jul 13, 2020 9:13 pm, edited 1 time in total.

MichaelG.
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Re: Build Your Own Needel Puller, Part Two

#2 Post by MichaelG. » Sun May 24, 2020 6:06 am

Excellent idea, Keith

Thanks for the description

MichaelG.
Too many 'projects'

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75RR
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Re: Build Your Own Needel Puller, Part Two

#3 Post by 75RR » Sun May 24, 2020 7:15 am

Interesting! Be nice to see a video of it in action.
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Hobbyst46
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Re: Build Your Own Needel Puller, Part Two

#4 Post by Hobbyst46 » Sun May 24, 2020 9:08 am

The simple and effective design and the detailed documentation are excellent. Thanks for posting.
From my own experience with glass pulling, the key to success is to just reach the softening temperature and not higher. Glad to read that your design overcame this challenge.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Charles
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Re: Build Your Own Needel Puller, Part Two

#5 Post by Charles » Sun May 24, 2020 9:44 am

Excellent design and results Keith!

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Re: Build Your Own Needel Puller, Part Two

#6 Post by Wes » Sun May 24, 2020 10:07 am

Very nice design.

I wonder if you add a conductive coil around the middle portion of the tube and apply voltage/current until it starts glowing would that make the needle pulling more reproducible.

keithstout
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Re: Build Your Own Needel Puller, Part Two

#7 Post by keithstout » Sun May 24, 2020 3:40 pm

I'm sure it would. My hand held open flame will always be subject to variability, especially when my morning coffee wears off. I have to control torch position and duration of flame/glass contact. A heating coil would simplify that to controlling only duration, which requires a mere push of a button. I think a heating coil could be installed on this puller.

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Re: Build Your Own Needel Puller, Part Two

#8 Post by Wes » Sun May 24, 2020 8:53 pm

I'm not sure if they even sell these anymore (professional needle pulling machines). So your contraption could find a good market (among diatom entusiasts and such).

I've been messing around with a alcohol lamp trying to get it just right, it took a lot of wasted capillaries but I think I got the hang of it now.
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keithstout
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Re: Build Your Own Needel Puller, Part Two

#9 Post by keithstout » Sun May 24, 2020 10:25 pm

These look like fine needles, Wes. I wish I had hands that good.

Yes, professional needle pullers are still manufactured. Sutter is one. They are capitol equipment, easily costing north of $20,000, far beyond the means of the diatomist. Engineers arrange digital control over the heating/pulling apparatus, and can therefore produce any kind of needle desired, be it for herding diatoms or injecting cells. These pullers are so precise that stray air currents must be eliminated, as well as any contaminants on the capillary tubes. Some deliver a measured puff of gas on the glass as the pull begins to set a certain viscosity to the melted glass. Engineers pay careful attention to the way the glass flows over the needle tapers' shoulders. The operator takes careful notes of the puller's settings when an ideal needle is made. Those settings are entered by keyboard into digital memory as a pulling program. Multiple programs can be stored, which makes a needed needle a mere button push away. Still, the operator must understand the relationship between heat, speed of pull, and length of pull, and glass type. Needle tips made by these pullers shrink to 0.2microns and smaller.

There are professional needle pulling services, but prices per needle easily top $150!

Thankfully, pulling the diatomist needles isn't quite that critical. Actually, it's sloppy work compared to professional pulling. The tips of our probes have about 5micron diameters. My puller can get smaller than that. My job was to study what these sophisticated pullers do and imitate them, eliminating the error of human touch as much as possible, establish consistency, while providing adjustability to create various needle types. Human touch still corrupts the heat application in my setup. I don't quite have my heating method refined, and I can't tell you if that is a perishable skill. Despite that, I currently enjoy an 85% success rate of needle pulling. I stopped pulling before I could refine my heating technique because I ran out of places to store my needles. For even my "failures" were making good needles; I was just trying to get them a trifle less wispy. I was just a flicker of flame from perfection!

Now I know how Robert E. Lee felt when he saw Wash., D.C. only a few miles away from a hilltop, undefended, ripe for the taking, but his army couldn't take another step, it being starved, exhausted, barefooted, dehydrated. My only consolation was that I'll live to pull another day. :)

I had no temptation to make and sell these pullers or sell pulled diatom needles. So much has been given to me that I wanted to contribute in some humble way and nourish the brotherhood of diatom herders.

Leitzcycler
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Re: Build Your Own Needel Puller, Part Two

#10 Post by Leitzcycler » Tue May 26, 2020 7:23 pm

This looks all very fine. However, as I know nothing about diatomes, could you explain for what purpose you actually use these? Is "needle" solid or are these capillaries? If capillaries, you could make microinjections to egg cells :) . I am just curious...

Hobbyst46
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Re: Build Your Own Needel Puller, Part Two

#11 Post by Hobbyst46 » Tue May 26, 2020 9:05 pm

Wes wrote:
Sun May 24, 2020 8:53 pm
I'm not sure if they even sell these anymore (professional needle pulling machines). So your contraption could find a good market (among diatom entusiasts and such).

I've been messing around with a alcohol lamp trying to get it just right, it took a lot of wasted capillaries but I think I got the hang of it now.
These are beautiful - very uniform and pointed.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Charles
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Re: Build Your Own Needel Puller, Part Two

#12 Post by Charles » Wed May 27, 2020 2:34 pm

Those are some fine glass needles Wes!
Leitzcycler wrote:
Tue May 26, 2020 7:23 pm
This looks all very fine. However, as I know nothing about diatomes, could you explain for what purpose you actually use these? Is "needle" solid or are these capillaries? If capillaries, you could make microinjections to egg cells :) . I am just curious...

These are used in picking/sorting diatoms from one slide to another. You can pick off diatoms from a strew to another slide to be mounted individually or in groups. For the purpose of diatoms, they should be solid needles with no capillary action.

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Maryfox
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Re: Build Your Own Needel Puller, Part Two

#13 Post by Maryfox » Mon Jun 01, 2020 12:49 pm

OK, I'm a beginner so I need some education on this.
What is the purpose of the needle?
Where is the needle to be pulled? Embedded in something?
Why pull the needle? to reuse it?
Looking forward to learning,
Mary

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75RR
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Re: Build Your Own Needel Puller, Part Two

#14 Post by 75RR » Mon Jun 01, 2020 1:47 pm

This thread reminded me of a video that Charles posted a while ago. I was impressed then and am still impressed now ...

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Charles
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Re: Build Your Own Needel Puller, Part Two

#15 Post by Charles » Mon Jun 01, 2020 2:13 pm

Maryfox wrote:
Mon Jun 01, 2020 12:49 pm
OK, I'm a beginner so I need some education on this.
What is the purpose of the needle?
Where is the needle to be pulled? Embedded in something?
Why pull the needle? to reuse it?
Looking forward to learning,
Hi Mary, Pulling needles means making glass needles from capillary tubes. These particular needles are then used to move diatoms from a strew, which has broken diatoms, sand and other particles to a clean slide for permanent mounts.

You can see the needle in use in this video also:
https://www.youtube.com/watch?v=g-F0Id_m3Ys

Leitzcycler
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Re: Build Your Own Needel Puller, Part Two

#16 Post by Leitzcycler » Mon Jun 01, 2020 7:14 pm

I really appreciate this fine work. I assume the needle is fixed into a micromanipulator? Pictures of those would be nice to see, especially if they are self made.

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Re: Build Your Own Needel Puller, Part Two

#17 Post by Charles » Mon Jun 01, 2020 8:37 pm

Leitzcycler wrote:
Mon Jun 01, 2020 7:14 pm
I really appreciate this fine work. I assume the needle is fixed into a micromanipulator? Pictures of those would be nice to see, especially if they are self made.
I use a micromanipulator made by Prior. I use a hypodermic needle to put the glass needle on and then onto a brass rod which is held by the micromanipulator. There are other types of micromanipulators:
Needle on Manipulator.jpg
Needle on Manipulator.jpg (100.33 KiB) Viewed 1477 times
And here is a handmade brass one:
Brass Micromanipulator on Ortholux.JPG
Brass Micromanipulator on Ortholux.JPG (103.15 KiB) Viewed 1472 times

keithstout
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Re: Build Your Own Needel Puller, Part Two

#18 Post by keithstout » Sat Jun 06, 2020 11:11 pm

I thought I'd post the solution to my wispy needle problem. Maybe the example will help someone out there troubleshoot his own pulling technique/apparatus. I needed to reduce the needle's taper and needle length and reduce the shoulder's radius.

I made three changes. First, I bought another shaft. It forms a tighter fit with its three components, reducing 80% of the play. I expected the improved precision would increase the shaft/drop weight friction. This will slow the needle pulling speed, giving me a larger timing window with which to properly stop the heat when the pull begins. This in turn will reduce the shoulder radius and the needle taper.

Secondly, I shortened my two step pull from 6mm/4mm to 5mm/3mm, which helps reduce taper/needle length. I like a two step pull; it is ideal for thin walled capillaries. With the second pull, I can re-center the flame onto the capillary's hourglass, which optimizes the needle's shoulder formation. It's so easy to do on my puller.

Finally, I moved a paper clip along the flame of my torch. Watching the clip's glow, I identified the coolest part of the flame, which was well in front of the flame, about an inch. This showed me I was pulling needles with the flame much too close to the capillary, overheating the glass. I made the next pull using the flame's coolest point, facilitating heat control.

I loaded a capillary and got an ideal probe right away. The shoulder to tip length is a fraction of my wispy needles. The needle is fine enough to handle small diatoms. It is flexible enough to take a bump on the slide without breaking. And it is stiff enough to nudge loose a stuck diatom. I found the sweet spot.

Looks can be deceiving. To my unaided eye, my probes were beautiful, their long tapers and needles giving the impression of precision implements. But under the scope, the problems surfaced: a little too soft and wispy. This time I inspected the next probe under the scope first. Having determined its virtues, holding it along side one of my earlier products made it look stumpy and ugly. But stumpy and ugly is the new beautiful. I can now detect pulling problems before I turn off the torch.

Perhaps the following relationships might help folks with their pulling process, be it hand or apparatus:
Heat
Increased heat will promote smaller tips and longer tapers. Decreased heat will promote larger tips and shorter tapers. Avoid high heat.

Pull Velocity
Increasing pull velocity will make smaller tips and longer tapers. Decreasing velocity will make shorter tapers and larger tips.


Delay of Pull Once Heat is Removed
Increased delay will shorten the needle taper. Decreased delay lengthens the needle taper.

Multi stepped pulling
Limit your needle pulls to 2-3 steps for thin walled capillaries. Too many steps in a pull can splinter the tips. The capillary should make a symmetrical hourglass shape when the pull begins. Proper hourglass shape ensures good tip formation.

In all cases, avoid excessive variables. For example, if you find yourself pulling needles with high velocity/force, it indicates problems with other variables in your pulling process. Heat may be too low, for example.

Keith

Charles
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Re: Build Your Own Needel Puller, Part Two

#19 Post by Charles » Sun Jun 07, 2020 1:40 pm

Keith, Good job getting the kinks worked out an fine tuning your puller.

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