Making PAF Slugs?

[David Schwab]

I think the idea of buying an old screw machine would turn into a nightmare scenario.

You mean you might get screwed?

OK.. I need some sleep...

[Possum]

...

I did a google on those kinds of lathes, looks like they are all in the UK and New Zealand, UK Ebay have one for sale for 600 pounds, pick up only.

[David King]

Yeah we might as well give up the ship now.

[Bruce Johnson]

Again, a small non-automatic turret lathe (the Brits call them Capstan Lathes) will spit out pickup slugs in 1-3 seconds a piece. That can include a bevel on each end it you set up for it. That's the least expensive and simplest machine to set up for parts like these slugs.

That lathe that you pointed out is essentially an automated turret lathe. It'll have similar functions and speed as a turret lathe, but you can stand there and watch it run hands-off. It'll feed bar stock and do 2-3 simple operations with tool bits.

A screw machine is like that automatic turret lathe, but with 4-6 additional automated functions that come in from all directions. It'll do a sequence of 6-8 operations with different tool bits and heads coming in and out, in precise timing. It's all set up with cams and stops.

Pickup slugs are simple parts. If you only need a few hundred of them now and then, just get a turret lathe. You can set it up in ten minutes and run a few hundred parts in an hour. Unless you need tens of thousands of parts, an automated lathe or screw machine will take you longer to set up than it will to run the parts.

[Possum]

....

How do you set these up to do bevels? I looked over my real PAF slugs tonite, I'm certain now they were hand beveled, the bevels aren't all the same, no uniformity there at all....

[Possum]

...

Here is a turret lathe, I don't see how you could set this up to cut and bevel slugs on both ends, I don't think this machine would be any faster than what I'm doing:
[ame="http://www.youtube.com/watch?v=tUt3P2_lfm0"]YouTube - Hardinge Turret Lathe[/ame]

[jonson]

If your talking about the one Iv'e put up Bruce then no that is not automated thats hands on. lever operated and still fast. Possum a parting tool ground in the centre of a bar, say 1/4 or 3/8 and the bevel cutter is ground either side of that so that the bevel goes on just as the final part through occurs. That could account for the uneveness as it would start to miss as the slug drops away.

[Possum]

...

Aaaah ok I gotcha. Wow that would be a tricky sharpening job, those bevels are about .010" very small, the slug wants to fall off and take a small nub sticking out with it, would probably take hours to make a tool that would bevel and not leave a nub sticking out. The timing of that would be super tricky...

[David Schwab]

...I don't see how you could set this up to cut and bevel slugs on both ends...

My guess would be that you would use a V shaped tool to introduce the bevel, and then part the piece in the center of the V groove with another tool.

[peskywinnets]

Forgive my naivety here (I'm coming into the world of pickups/coils with an electronics background, but not necessarily up to speed with all the common terms!) .....a slug is a pole piece? (& normally nickel coated steel)


I'm actually making my own pole pieces at the minute - I need them about 5.8mm high x 6mm dia (which I'm unable to source), here are some related queries....

1. The proper pole pieces (slugs) are nickel coated steel ...I'm presuming the nickel coating is to make them look nice & stop them rusting?

2. Steel type ....is there are prescribed type of steel that's deemed best for making pole pieces - I'm figuring some form of steel with a high iron content & little carbon content? (wouldn pure iron be best? - with some form of coating to stop rust?)

3. Getting a nice finish (both surface finish & bevelling...which I can see has just entered the discussion on the posts that precede mine!)


So, if anyone here makes their own pole pieces (or who *knows* how to do it properly....would they mind sharing how to churn these out at high volume?!!!

[Bruce Johnson]

The standard technique is to stack three cutoff blades side by side. The center one is ground square, and the outer ones have left and right bevels. Then you adjust them by trial and error so that just as the center one cuts off the slug, the outer ones have cut a slight bevel on either side.

Fancier tool holders will have the two outer blades spring loaded and able to slide as a pair independently of the center blade. That will make a more precision bevel. The bevel blades will make their cuts when the center blade has just started, then they stop at an adjustable depth while the center blade continues and cuts through. Mounted in a turret lathe, that whole operation takes about a second.

There are simpler ways too. Most lever-operated cross slides, such as the ones I have on my Logans, have tool block mounting pads both ahead of and behind the spindle. So, I can set up a V-shaped tool bit on the back pad (upside down, of course), and a single cutoff blade on the front pad. They each have independent depth stop settings. Now, I pull the lever back which makes a V cut of a fixed depth, then push the lever forward which cuts the part off, leaving small bevels on either side. The double action of the lever takes slightly longer per part, but the tooling setup is much simpler.

This is all really old-school stuff. I have textbooks from 1900 which teach apprentice machinists how to do tooling setups like this. One of the sweetest antique machines in my shop is a circa 1904 Bardons & Oliver No.0 Turret Lathe. I'm currently restoring it and will have it making guitar parts someday soon. Back in its day, it was primarily sold to bicycle shops, and the ads claim it could turn out 8000 spoke nuts in an 8 hour day. Just provide one poor sweating teenage apprentice!

[Bruce Johnson]

Peskywinnets:

The slugs are typically made on a turret lathe or screw machine, just like we're talking about here. They're usually made from plain mild steel bar stock, something like 1018 or one of the free-machining steels like 12L14. After the parts are machined, they are nickel plated to keep them from rusting.

The level of finish and the quality of the finished parts depends on using good technique, and how much time you want to put into them.

Be aware that the nickel plating is about 0.001-0.002" thick, so it will slightly increase the diameter and length. You have to consider that when you design the parts and how they fit together.

Whether and how different grades of steel affect the tone of the pickup is a whole other subject, which I know nothing about and won't even speculate on!

[David King]

Possum,
watch that video again, he's doing 7 different operations not including the initial overhang of the bar in the first sequence. The beveling is the second to last op just before the cutoff, he uses a V shaped cutter just as David and Bruce have described to bevel the back end of one part and the front end of the next in the same stroke.
If he weren't talking the whole time and running the lathe without coolant and at 1/2 speed, he could be turning out a threaded nipple in under 10 seconds. You only need two operations and don't even need the turret, just the lever actuated cutoff along with a swing out gizmo to set the part length. That lathe will blow the doors off yours with the 3 jaw chuck. I have the same Hardinge DSM and it crushes my 9x20 in every way for repetitive parts. If we didn't live in freakin wild Oregon we could pickup a DSM like that for $400.

[Possum]

.......

So is there a crossslide like his that you could get for the Harbor Freight lathes? Sure would save some time. I don't see how you could do the bevel and cutoff from one side without complicated setup or moves.

[Peter Naglitsch]

[QUOTE=kevinT;120934]That is a killer machine....love it.

Allparts has the smooth surface slugs the last time that I bought them. QUOTE]

Mojo has bulls eye pattern slugs (IRL the plating looks much better than in that pic):

They are 2$ for a 6 pcs set and if you contact them you will get an OEM discount. In the end I don't think it is worth the time and money to make your own if you can buy good looking slugs for 20 cent each if you consider the time you need to maufacture these and the cost of having them plated. Of cause it all cooks down to how you value your own time.

If you are unsure about the quality why don't you contact Mojo for a sample. That whay you can compare the look of their slugs and the originals you are replicating. And even report back to us unfortunate once that don't get to lay our hands on too many original PAFs and really can't make that judgement