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Wadkin JY bobbin sander drums (roll your own)

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tool613

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The Wadkin JY bobbin sander is a great machine and was supplied from green lane works standard with a 3.5"X9.5" bobbin in the 40s/50s. You could could special order 3 other bobbins in 5", 2.5" or 2" all 9.5" long. These steel drums you would load your own flat paper and the device works extremely well. My machine only came with the 3.5 and so i want to come up with a way to fit other sizes. Finding OEM bobbins would be like finding a piece of straw in a stack of needles. these thing are as rare as hens teeth.

The JY is a fixed spindle 1 1/4" and that is why wadkin's smallest bobbin is only 2". it would be nice to have smaller ones. Some of the solutions to fitting bobbins is to turn the shaft down and use rubber drum from new bobbin sander. Most are 3/4" ID and this would work but would leave the shaft not as strong as wadkin intended the shaft to be. the rubber drums as not cheep ether and cost a good chunk of cash to out fit my machine. I did not want to go this way and lose the use of my only OEM self load bobbin. Reaming the rubber drums or having them made with an 1 1/4" bore is costly too and was out side what i wanted to spend.

Here is what I came up with and it may help those who find that they are in need of bobbin's for there sander and want to roll there own.

Its starts with what we call in Canada cow mat(1/2" rubber mat for the dairy industry).


I set the drill press up with a 1 1/4" bit and drilled the ID and cut the OD large on the band saw. you need 2 disks per bobbin size you are making .

You need a mandrel to hold the disks on the lathe That is the same ID as the drum you are making and just undersized to add box tape and paste wax to so wood glue will not stick. The idea here is to make drums in wood and have the two rubber disk grabs the paper when the bolt is tightened .

The core I made of Baltic birch grade AAA-BB . Ii glued up layers before drilling the core.


I use a bushing on the mandrel that sticks out past the end to glue the section together on the lathe. I do not glue the rubber disks in yet until I have turned down the core close to size. The mandrel has a shoulder on the drive side so a piece of wood between the tail stock clamps up the work.

I drilled a taped set screws inthe bushing to hold the core on the mandrel and I set them when I am ready to spin the core. I take the pressure block out of the tail stock and set the live center. the Wadkin RS cross slide is great for this but you do not need it.


I turn the core down to just over size and wthen I am ready to glue in the rubber disks. I tried many glues but by far the best was the band saw tire glue I had left over from my Bursgreen BZB Band saw rebuild.


I use the mandrel to clamp it up again but do not set the bushing set sewers until the glue is dry. then let of the pressure on the rubber and set the bushing screws to hold the core and finish spinning.you don not want to compress the rubber when you tune to final finish.
I sand to my final fit . you just want the paper to just slip on.




I was able to make sizes from 1 1/2" to 4" @ 1/2" apart. I think i will make 3 of each size so i can have 3 grits for each bobbin size. On a week end I could make 10 of theses.

thanks for looking

jack
 

OPJ

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Thanks for sharing this, I think it's an excellent solution! I've been thinking of making a 3in bobbin for my Jet BOS-5 sander (without the insert plate, they cost almost one-third the price of a new machine!! :shock:) and, as I already have a spare spindle for this model (one of the original bobbins was 'faulty' and so, it was replaced soon after purchasing), I may have to borrow some of your ideas, here.

I'm not much of a woodturner so, instead of using the lathe, I may have to resort to a combination or router and jig. ;-)
 

tool613

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Olly
thanks for the comment.

My first generation cores where 1/8" thick rubber cut with scissors real close to the OD with 1" MDF in alternate layers carefully cut close to the OD. Glued it up on the sander and sanded it to size right on the machine. when you sand remember to not to compress the rubber to much under the spindle nut. They work just as good as my OEM one.

jack
 

CHJ

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OPJ":33tp8qym said:
......
I'm not much of a woodturner so, instead of using the lathe, I may have to resort to a combination or router and jig.
Olly, much easier to get a good fit if you can find someone with access to a pattern makers wood lathe, or a metal turning lathe within traveling distance, might be worth a shout in the turning section when you have your stacked mandrel pieces ready for final finishing, could be worth a day out from Bristol to get them finished off.
 

tool613

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CHJ":3t8g9tfb said:
Olly, much easier to get a good fit if you can find someone with access to a pattern makers wood lathe
Ya that does make it nice the pattern lathe. Have you ever turned rubber boys? I found it strange and I do not know what it is in rubber that dulls the HSS tooling so fast. If you have not tried rubber in the lathe you might want to start with slow RPM's with a HSS scraper. Not that I am a pro turner but I can spin things.

very nice to have the chaps that have the tooling to help you thought.

jack
 

CHJ

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tool613":2z6ijawg said:
Have you ever turned rubber boys? I found it strange and I do not know what it is in rubber that dulls the HSS tooling so fast. ...
We always froze rubber with liquid nitrogen when turning to critical size, I think it will be the Silica fillers used in the particular stuff you have that is dulling the tooling.
 

tool613

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Chas
liquid nitrogen is little hard to come by, but February in Canada is cold enough that on takes note of wind direction when makeing yellow snow. Problem is the machines freeze up too.

jack
 

OPJ

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Thanks for your replies. Adidat - I may have to take you up on that offer, in the coming weeks. Thank you. ;-)

The bobbins on my machine are slightly different to the ones that fit the Wadkin sander above. Hopefully, this picture will allow you to see that... It is, unfortunately, the best photograph I can find:



Smaller bobbins (less than 1½in, IIRC) have the sleeve fitting directly over the steel shaft and that is then held in place by a clamp and steel screw:



Larger bobbins though, first have a rubber sleeve that sits over the shaft and then, the abrasive sleeve slips over that (no clamp). There is a nut that tightens down on top of a rubber washer on the top end but, I'm not sure whether I could get away with simply covering both ends with rubber?

So, if I build my new sleeve from birch ply, do you think I would also have to line the outside with some form of rubber? I do have some spare bandsaw tyre, about 5mm thick (30mm wide), which might be usable.
 

CHJ

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Good to see the project earning it's keep, and with that quality of shop made accessories good for many years of satisfying use.
 

tool613

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CHJ":3pcy2qew said:
Good to see the project earning it's keep, and with that quality of shop made accessories good for many years of satisfying use.
Chas the Wadkin Kit is just so nice to use its a joy each time. Thanks
 
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