Bobbin Support

[NightWinder]

I am curious....what are some materials that you guys are using between the top and bottom of the bibbin- Ie: the middle . Wheather it be for a P90, or a similiar design. I mostly use hard maple, and I have used plastic, but wood works great. I never really seen anyone mention this sooo..

[Spence]

Note quite sure what you're referring to. Wouldn't you use a pole shoe for a P90?

[NightWinder]

Between the top and bottom of a bobbin> where you put the screws. Cut off the top and bottom of a bobbin. That piece.

[Spence]

I have used maple but the plastic would be the normal thing to use.
Early P90's were made with black perspex. You can easily do this yourself if you can source black perspex.

[Possum]

are you talking about the coil former part or bucker spacers? Are you making your own bobbins? When I made my own P90s I used plastic that Lollar recommends in his book, I forgot the name, its not plexiglass, plexi shatters when you tap it. That stuf works but you have to run the tap through it multiple times to get a clean thread. Maple would be ok but probably over time if you mess with your screws alot would strip out.......

[NightWinder]

Yeah, the maple does strip, but not fast. I've been using the same bobbin for protos for 2 yrs and the screws are still tight. Minor adjustments for screw heights are fine. Also finding the start of the thread and not jamming shit together is always a plus.
So, noone is useing perspex??? I'm looking for some alternative choices. I am aware of some plastics, and am ready to try some new ideas. I wonder....CPVC come in black. That stuff fusses together, and would never come apart..any Ideas, or supplyers out there for the perspex? Is there a better alternative for perspex?

[David Schwab]

Originally Posted by NightWinder

So, noone is useing perspex???

I think Perspex is what we call Lucite (acrylic) here in the States? That should work fine. I know you can put screws in it, because I made a guitar out of the stuff!

Lexan would probably be good too. Plexiglas is too brittle. I don't think they make that stuff anymore. Rickenbacker use to make their pickguards from plexi.

What are P-90 bobbins made from? Butyrate?

[Zhangliqun]

I think the plastic Lollar recommends is lexan. I bought some to make some humbucker-spaced P90's with slightly taller bobbins. It works very well.

[Possum]

the generic term I think is polycarbonate. I hate that stuff, you run a tap through it then you have to run it through again twice to clean it out, you spend hours tapping the stuff, it doesn't crack and is real durable though. Its also extremely dangerous to use on a table saw. Its real grabby and cutting small pieces frequently turn into plastic bullets. At Tap Plastics they have alot of horror stories, one employee had her eye shot out. I bought a tiny mini-table saw and it shot holes through some real tough stuff I put up as a barrier. They do cut it on a table saw at Tap but they won't cut small pieces because of the dangers.

A side question, whats a good source for 1/8" thick maple to make spacers from? I've been using basswood from the hobby stores, its just the right thickness and easy to cut......

[NightWinder]

Pm for you about the maple.

[David Schwab]

Originally Posted by Possum

the generic term I think is polycarbonate.

Yeah, that's Lexan.

Originally Posted by Possum

I hate that stuff, you run a tap through it then you have to run it through again twice to clean it out, you spend hours tapping the stuff, it doesn't crack and is real durable though.

Makes that gummy mess that melts back in the hole? I hate drilling plastics because of that. I have heard that there are drill bits made for drilling plastic, but I've never seen any.

Originally Posted by Possum

Its also extremely dangerous to use on a table saw. Its real grabby and cutting small pieces frequently turn into plastic bullets. At Tap Plastics they have alot of horror stories, one employee had her eye shot out.

Ouch! I always wear a full face shield when routing and sawing stuff....

Originally Posted by Possum

A side question, whats a good source for 1/8" thick maple to make spacers from? I've been using basswood from the hobby stores, its just the right thickness and easy to cut......

How's this?

Constantines:Hardwoods/Lumber > 1/8" Thin Maple

I used to buy a lot of veneer from these people.

[Zhangliqun]

I cut it with a mini-bandsaw with a miter. No trouble with flying shrapnel so far...

[NightWinder]

thats too expensive!

[jonson]

Hi Guys. Poke my nose in here as you guys are walking right up my alley at the moment. so maybe some info. David is correct in the fact of Perspex and Lucite being the same product and both are Acrylic. Cold cast and and extruded are the 2 methods of manufacture and the one to go for is cold cast. Easier to machine and leaves a far better finish and easier to polish as well. As to how to cut it then you are looking at Solid Carbide Helix Spiral cutters. ordinary Straight flute Tungstan Carbide cutters are fine for Partical board such as MDF and High speed steel cutters are good for Timber (softwood or hardwood) but a spiral cutter is the requirement for Plastics.
Perspex routs well providing you cut the material down to size and only remove 1/16 to an1/8 of an inch with the router allthough you can go through in steps, an 1/8" deep at a time. the stuff thread taps clean if you use a good quality high speed steel tap as carbon steel taps do not carry the edge needed. Make sure your tapping drill size is correct as too small and you will just make the hole bigger and two big leaves a weak thread. Drilling plastics is down to the angle of the drill point. Standard Twist drills are ground at about 60degrees and this is what causes the snatch as you come through the other side, unless you have the material locked down tight to a backing board and you are feeding very slowly. The game is to grind the drill back to 30degrees almost a needle point as the drill will then feed through slowly and you do not get the snatch etc. Ideal point on a drill also if you want to enlarge an existing hole as the drill will follow the origional and not recut off centre. I've been through a lot of cutters over the years and have now found the best of the lot over in the USA.http://www.plasticrouting.com/
Guys in England can buy from Router House Midlands LTD. 0116 232 1111. and these beasts are not expensive but far sharper than anything else on the market. David you will will find your plastic drills here as well. I normally rout Perspex and forbon with a downcut spiral cutter with the work held down with double sided tape and never had throw out and still have 10 fingers after 60years so as long as you go by the rules with the right tools for the job you will be ok. Nightwinder not forgotten you but since I paid for the items they have now become out of stock(never were in stock) Typical UK company and have given me 6 to 8 weeks delivery so as soon as they arrive they will be in the post to you. Sorry this is so long guys but even this only covers a bit of the subject. Jonson.

[Joe Gwinn]

Originally Posted by Possum

the generic term I think is polycarbonate. I hate that stuff, you run a tap through it then you have to run it through again twice to clean it out, you spend hours tapping the stuff, it doesn't crack and is real durable though.

Yes, Lexan is a brand of polycarbonate.

It does not take hours to tap lexan, if one is using sharp high-speed steel taps, cooled with ordinary tap water. Taps bought in hardware stores will not do.

More generally, if something that common and simple takes hours versus minutes, it's time to start asking questions.

Its also extremely dangerous to use on a table saw. It's real grabby and cutting small pieces frequently turn into plastic bullets. At Tap Plastics they have alot of horror stories, one employee had her eye shot out. I bought a tiny mini-table saw and it shot holes through some real tough stuff I put up as a barrier. They do cut it on a table saw at Tap but they won't cut small pieces because of the dangers.

I don't know why they use a table saw at all. Bandsaw works very well, won't throw things, and is far less likely to trim someone's fingers off.

[Possum]

its pretty hard to cut a perfectly straight piece on a band saw. the parts we're talking about here are .25" thick by usually .25" tall x about 2.5" long. Tap does cut the stuff on a table saw but they use a special blade. I'm not sure a high speed anything would work on polycarbonate it doesnt like heat either. I quit making most of those pickups due to the problems with tapping it.....

[madialex]

Originally Posted by Possum

its pretty hard to cut a perfectly straight piece on a band saw. the parts we're talking about here are .25" thick by usually .25" tall x about 2.5" long. Tap does cut the stuff on a table saw but they use a special blade. I'm not sure a high speed anything would work on polycarbonate it doesnt like heat either. I quit making most of those pickups due to the problems with tapping it.....

Just an idea here but wouldnt a tile saw cut it good, the water would keep it cool and not do the melting thing and would be a smooth cut because they cut a lot finer, there would be less danger of binding up with melting and causing shrapnel to put eyes out.

Just a thought???

[jonson]

there is no prob using a table saw if you do it right. I quite happily cut .25 strips off 8' x 4' sheet and don't always bother to change the blade. the prob is the attack angle of the teeth doing the cutting. If you take a 10" blade and just feed plastic through the front edge of the blade it is cutting down into the material and knocking it about like a jack hammer so you have to drop the blade down. If this is not possible then lay several pieces of MDF or ply on top of the saw table so as the blade is now only showing 5/16 out of the table. The cutting now becomes a sliceing action cutting the underside first and elliminating any smash out.The correct blade to use would be a triple chip but standard saw blades do work but just dont give as good a finish.As with all plastic cutting hold the material down tight to stop any bounce, even on a band saw make sure there is a false board underneath so there is a much smaller gap under the saw to back the material up. This works with aluminum sheet as well allthough certain grades do tend to throw off fine chips which sting the arms but if set right on the waste will come off the blade as a long thin curl as if you were turning it on a lathe. The correct lubricant for Perspex cutting is white spirit though not sure what you guys call that in the States. Polycarbonate would only worry me if it had any form of lacquer put on it after machining as it then changes structure and can shatter. Happened to a lot of motorbike crash helmets over here back in the 60s. People painted them and they became useless (bloody dangerous)

[NightWinder]

No worries, as you can see, I'm replaning my construction!!LOL Funny, thats always the case.....seems it happens over there too. I feel better, LOL, it does'nt just happen to me!!!Glad to see you post some informative material. Well appreciated. Nice retirement spot by the way!!! Absolutly beautiful!! Thanks for sharing that brother!!

[EtLa]

Originally Posted by jonson

the prob is the attack angle of the teeth doing the cutting.

You can also put the blade in reverse for cutting plastic.

[Satamax]

The solution for cuting drilling, tapping plastics, "negative or neutral rake angle" For bits, do it like this.

[NightWinder]

I Just recieved Multipul catalogs from Onsrud from jonson mentioning it. Their stuff is specifically designed for plastice, and different drills for different plastices too. Check them Out!! Their really on their game, and are very fast to send any cataloge you request for multipul materials....Loos like this company is top notch!.
www.onsrud.com - Thank Jonson for the hit>

[Satamax]

Nightwinder, for drill bits a litle diamond file or grinder is enough to flaten the lif for no rake angle. As showed in teh pic.

[NightWinder]

So, it would work essentially just as good? thiers are kicked back 60 degress, but you may be right....looking at how much on bit costs....holy shit

[NightWinder]

Forgot, and thier routing bits for Forbon....Did you stop by the site. All their stuff is relivant to the materials....just trying to decide which would be best for Forbon?(asking) In your opinion.

[jonson]

Not sure after 40yrs of running saw blades ranging from 1" to 24" diameter I would ever want to run a blade backwards. The teeth taper from front to back and top to bottom which is why you only sharpen the face not the sides and this applies to router cutters as well. The tooth cuts and then clears, so, running it backwards you are wedging your way through the material and gonna get one hell of a jam up one day. That's a dodgy shortcut. The angle I was refering to on a drill is not on the face it's the angle of the point. Make it longer so the drill point takes a lot longer to pass through the other side and prevents a lot of break out. Spur points work well( think you guys over ther call them brad points) but you still need to hold the work down tight to a backing board. Main thing I'm pushing here is safety but good clean work at the end as well.Nightwinder you wait till you get one of those cutters, they have a mirror finish and the swarff comes off the cutter like dust if you are set right.

[NightWinder]

I'm going for it!! Thinking I may need a few, spacifically a router bit for the forbon for rails, and a drill bit for clean precise holes. The Punch methods gets the job done, but is way too undersized, and when pushing the forbon over the mags are way to tight. Way much more time that it should be. I was thinking the PCD Roughing& finishing tool. Made for carbon fiber- G-10, and other fiberglass. Or the 63-600/900- all porpous for interior and perimeter routing(spiral flute)

[jonson]

Hi Nightwinder. can't comment on the pcd as not having a cnc router have left them alone. but for ruffing out would do the trick. Phone the guys at Onsrud up and talk as they won't bullshit you. The downcut left hand spiral will work and not sure if you are using a hand held router or you have it fixed which for small work is easy to do with half a sheet of plywood. If i'm working big (2" or 3") lumber then I use a big fast overhand router but for forbon and small plastic stuff just the router jigged in a cradle. Will take some pics and post. For the hell of it had f/all to do today so made a clone early Shatten winder out of PERSPEX!!! clean cut. clean drilled and clean tapped and nothing dodgy. Just need to take apart and sand and polish the edges. So can be done allthough took me 3hours and wouldn't make any money doing that as a production item.

[NightWinder]

I was thinking more simplistic. Making one hole at an end of the forbon, where the blade would end, and using the t-stop to keep it strait feeding it through the desired distance along the bar. using basically a drill press, but it is rather more a mini jewlers press, with about a 8,000 rpm max. Very simple. Did'nt mean to confuse with the cnc bit.....just thought the bit would work for the application better. I'll compile up some photos of the machine, and such and send you an e-mail later tonight. I think I will be calling them tomarro morning. Remember, they are about 3 hrs from me, so If they are really reponsive, I may take a trip down there with some precut Forbon. This is such High Quality stuff man.... Took 2 days to get a bunch of different catalogs from them. Really responsive. With all the materials, special tooling for them, I bet they would be more than happy to help.

[jonson]

I don't think you will be dissapointed with their cutters as it is "horses for courses". don't think your boys wen't into Iraq with water pistols. so it is the right tool for the job. My set up for milling forbon and small perspex items not costly and very very safe. Plus what can be done with plastics in a few hours with the protective film still on it. Finish it next sunday.

[Satamax]

Try for yourself, you'll see!

[jonson]

Biggest Problem we have here with that Satamax is the Uk Factories Act. Plus of course the dear old insurance company. Must be something like it for the EU as well. How did it happen This Accident. I put the blade in backwards.
End of Story.!!!

[Joe Gwinn]

Originally Posted by Possum

its pretty hard to cut a perfectly straight piece on a band saw. the parts we're talking about here are 0.25" thick by usually 0.25" tall x about 2.5" long. Tap does cut the stuff on a table saw but they use a special blade. I'm not sure a high speed anything would work on polycarbonate it doesn't like heat either. I quit making most of those pickups due to the problems with tapping it.....

When machining any plastic, especially a gummy one like polycarbonate, it's necessary to use sharp tools and to make sure that things are well cooled, so the heat of machining doesn't melt the plastic. That's why I flood the workpiece with ordinary tap water. It makes a big difference.

As for the high-speed steel, the reason for HSS is that the good taps are only made in HSS, not carbon steel (although carbon steel would otherwise work). Look for spiral-point taps, and do the deed underwater. You will have to order spiral-point HSS taps from MSC or the like. Local hardware stores do not carry such things. Avoid anything marked Hanson, Ace, or Irwin for taps and dies.

[EtLa]

Originally Posted by jonson

How did it happen This Accident. I put the blade in backwards.
End of Story.!!!

I'm not the only one who put blade backwards. http://www.homebuildercanada.com/1805TT.htm
Years ago you may have learned as I did to take a fine-toothed blade and install it backward for cutting thin sheet material - both plastic and metal. Now they make negative hook angle blades to accomplish the same clatter-free cut on both vinyl and aluminum siding as well as aluminum extrusions and plastic pipe

[jonson]

Gonna get out of this thread before I say something really stupid and there's too many nice guys here for me to do that. got you mixed up with Satamax man and I apologise to Satamax for that. But all I was trying to promote was safety and reading that artical you posted "was doing the same". As he said he did put the blade in backwards but they now make ANTIKICKBACK blades for the job and I bet that is now what he uses. There is probably a few guys on here totaly inexperianced with a table saw so I wouldn't want them to take short cuts. Made my point so I will leave it at that.