Budget Lathes and Presses for WTC endcap constuction

[warpatroller]

I thought I would start this thread to get some input on what some good budget lathes and drill presses might be for WTC end cap construction. Subculture Andy, could probably chime in here, as he has done this kind of thing, numerous times.. With a few units like the ones I have shown, perhaps for the cost of one commercial WTC, you could buy these machines, and make your own WTC. Then you could make additional WTC units, for much less in the future. If you're only interested in having one WTC and one sub, this route probably wouldn't be worthwhile for you..

This would also be good if you can't locate a commercial WTC unit that fits the particular model you're interested in building, and fits into the layout you'd like to have in your sub. Maybe currently available commercial units, don't provide you enough room for torpedo launchers, etc.. Or maybe you want a 2.75" OD WTC. Most commercial units are either 2.5" or 3.0".

Another good discussion would be how to make your own motor bulkhead endcap. So that you can attach the drive motor or motors, of YOUR choice, to the endcap, with a propshaft seal or seals installed in the bulkhead cap.

http://www.grizzly.com/products/10-x-18-Bench-Top-Wood-Lathe/H8259

http://www.grizzly.com/products/5-Speed-Baby-Drill-Press/G7942

[warpatroller]

Re: Budget Lathes and Presses for WTC endcap constuction

Here is the cheapest lathe I could find tonight.. An old, very, very well used Sears Craftsman piece that looks like its been sitting at the bottom of the sea for 30 years.
Bargain priced at $45. I like the alignment on the pulleys. No drive belt included, but the seller claims it works.. Fit for WTC Endcap turning? I kinda doubt it.. Who knows, maybe there is still a little bit of life left in it..
What a piece of junk.. lol The drive motor, looks like a midget sub "creeping" motor. It would be awesome to see world class Endcaps turned for an museum quality OTW VIIC on this old POS Reminds me of looking at old junky car parts..



I was watching Subculture's Encap video tutorials, and his lathe looks like it was very expensive. It looks very beefy, strong and thick. I notice you are not cutting into the blanks with hand tools, like what people typically use with these little wood lathes. What did your lathe cost, Andy? The cutting piece you have, could something like that be mounted to the little Grizzly or the old POS above?

[vasily]

Re: Budget Lathes and Presses for WTC endcap constuction

You're looking at wood lathes. With these, you hold a long chisel on a 'rest' and carve the shape you want into a spinning piece of wood. They make great table legs, but they are not meant to be precise. To make an watertight O-ring sealed endcap, you have to hold the cut dimensions to a few thousands of an inch.
Plastics machine like soft metal. The cutting tools in a metal-cutting lathe are held rigidly in a movable tool rest. You turn a dial, and the tool rest moves in, out, or over, a few thousandths of an inch. You need a metal-cutting lathe to cut precise end caps.
Look at a Jet, Grizzly, or similar 9X20 lathe. The bad news is that a serviceable used 9 x20 will be several hundred bucks.
If you want to try for cheaper DIY endcaps, you might look into casting them from a good urethane resin. You'd use a section of your tubing as the mold into which you'd pour the urethane (after coating it with release agent). You'd still have the issue of cutting or molding the O ring groove, which you'd have to MacGyver.

[Guest]

Re: Budget Lathes and Presses for WTC endcap constuction

The lathe in the video actually cost about £50 ($80), although that was almost 25 years ago!

A case of being in the right place at the right time- it had been decommissioned at the company I worked for at the time. Needed a bit of work to get A1, and also had to convert it to single phase.

It's complete overkill for machining endcaps though, so don't go thinking you need to have one of those to machine parts for a model sub.

As Vasily said, woodworking lathes aren't the right machine for this job, what you want is a small metalworking lathe. When I say small I mean small, plastics are very easy to machine with modest power, and unless you're building very large boats, you don't need a lot of swing.

A secondhand machine offers best value, and usually the best way to pick one up is if you're a member of a model engineering club. A secondhand machine will usually come with a whole heap of useful accessories that you'd have to pay extra for if buying new. However do buy something in decent condition- a worn out machine will not produce accurate work and can be a false economy.

If you have no secondhand machines available, and are looking to purchase new, then the Chinese Seig type machine available from various suppliers (Warco, Axminster to name but two in the UK) offer very good value for money.

Something like the micro lathe pictured below, which is only the size of a small domestic sewing machine, will enable you to make your own end caps and accessories for cylinder sizes up to about 140mm diameter. That should be enough for the vast majority of model sub enthusiasts.

It will earn it's keep with the first cylinder you make, but do bear in mind that a tool is only as good as its operator, so if you're new to turning and machining you may generate a few scrap parts until you get the hang of it.

[Guest]

Re: Budget Lathes and Presses for WTC endcap constuction

Regarding cutting tools I used a normal side and face cutter. For cutting plastic any high carbon steel will be sufficient, and most people will use high speed steel cutting tools (usually abbreviated to HSS). This is overkill for plastic, but they're handy for machining metals, as they hold an edge at higher speeds. Tools made from tungsten carbide are not necessary at all for the home machinist, and can actually produce an inferior finish.

Tools come in different sizes for different machines. You can purchase preformed/ground shapes, or purchase HSS blanks and grind your own. Tools tend to be modestly priced these days, and you only need two or three types for most machining work.

If you're a novice to lathe work I suggest grabbing a copy of 'Using the Small Lathe' by L.C Mason

http://www.amazon.co.uk/Using-Small-Lat ... 1857611187

This is an old book, but still relevant to the hobbyist. I find a lot of newer books gloss over too many points or try and encourage the purchase of expensive and unnecessary accessories.

When machining plastics, my advise is to stick with PVC if you can. This is a really easy plastic to work with, much nicer than polycarbonate or acrylic. Make sure your tools are razor sharp, and don't run the machine too fast.

[warpatroller]

Re: Budget Lathes and Presses for WTC endcap constuction

Thanks for the info guys! And thanks for taking the time to make those videos, Andy. Those are good resources.

That would've sucked if I had bought a wood lathe.. That's why you always have to research stuff before you run out and buy something.

Would this Sherline 4000, as equipped for $700, be able to turn 2.5" to 3" end caps with o-ring grooves? Or is there something else, not shown in the photo below, that is needed to add to the lathe to be able to do it?



It says the standard height above the bed is 3.5". Height above the carriage is only 1.88". Take The radius of the endcap, add some extra length to that, and you get the needed height to turn the cap. So 1.88 inches should be enough to turn a 3" cap over the carriage. When turning an end cap, does it need to clear the carriage, in addition to the bed?

There are a pair of optional riser block accessories that allow you to turn a larger blank. Increasing the height above the bed to 6" and probably the height above the carriage to 4.38". You're looking at an extra $120 for those parts though.

It appears this unit is made here in the states, in California, instead of China..

[Guest]

Re: Budget Lathes and Presses for WTC endcap constuction

That looks like a good little machine.

The swing of the lathe as standard should be adequate for machining up 6 3/4" diameter endcaps with the gap specced at 3.5" (don't forget you double this measurement for the disc size you can machine). Gap to the saddle allows you about 3.5" diameter discs, but don't forget that you can have the tool overhanging the saddle a bit to enable better clearance.

I don't think you will require the riser blocks, and the money would be better spent on cutting tools, perhaps a rotating/live centre and maybe a four-jaw chuck (unlikely you will use this much, but it's handy). You will also want a set of vernier callipers for measurement (some will advise a micrometer, but I never use them except for very high accuracy work) and dial indicator gauge will be useful if you feel the need for a setting up work in a four-jaw chuck.

You may also want to think about a small bench grinder for keeping your tools sharp, although hand tools/stones can be used to keep an edge.

So with that little machine you should be able to make endcaps and shaft seals and piston ballast tanks. The one part you cannot do which a larger machine might permit is to machine the edge of a wtc cylinder wall, but that can be achieved using hand tools.

[Wheelerdealer]

Re: Budget Lathes and Presses for WTC endcap constuction

I have one of those small Chinese metal lathes that Andy inked to. It does the job...

[warpatroller]

Re: Budget Lathes and Presses for WTC endcap constuction

Cool, Wheelerdealer!

Your WTC reminds me of the OTW units, with an Engle piston tank, instead of the water pump. Looks like a professional made that cylinder.. Look at that neat routing of wires and placement of the components. This guy knows what the hell he's doing! I sure don't!

[tsenecal]

Re: Budget Lathes and Presses for WTC endcap constuction

I have a taig lathe, with riser blocks, jacobs drill chuck, the tail stock, and the compound top slide.

with those i can turn basically anything up to 5" diameter.

http://www.taigtools.com/

[Wheelerdealer]

Re: Budget Lathes and Presses for WTC endcap constuction

Cool, Wheelerdealer!

Your WTC reminds me of the OTW units, with an Engle piston tank, instead of the water pump. Looks like a professional made that cylinder.. Look at that neat routing of wires and placement of the components. This guy knows what the hell he's doing! I sure don't!

Ha, no I didnt know what I was doing. That was my first lathe and those discs were just about the first things I tuned in my life. I remember picking Andys brains on which one to buy and how to hold the PVC disc. Its really not difficult. If you can build a sub, you can make end caps and WTCs. My second WTC was a little more elaborate.

[warpatroller]

Re: Budget Lathes and Presses for WTC endcap constuction

I don't think you will require the riser blocks, and the money would be better spent on cutting tools, perhaps a rotating/live centre and maybe a four-jaw chuck (unlikely you will use this much, but it's handy). You will also want a set of vernier callipers for measurement (some will advise a micrometer, but I never use them except for very high accuracy work) and dial indicator gauge will be useful if you feel the need for a setting up work in a four-jaw chuck.

So with that little machine you should be able to make endcaps and shaft seals and piston ballast tanks.

What would be the purpose of having a "rotating/live center" and a four-jaw chuck? I don't know what those are..

When you say I could make piston ballast tanks, are you referring to a free floating piston tank, using a free floating pvc piston with pvc endcaps and plastic/lexan tube? Or an all metal piston tank with a jack screw? Or, I guess both? I could make push rod seals, prop shaft seals, metal periscopes, and metal propellor hubs too.. A metal lathe seems like a nice piece of gear for a "real" RC sub guy (hey, that sounds like Nautilus Drydock Bob in Florida)..

To round out the gear, a drill press, band saw, grinder/belt sander, and a shop vac to clean up the mess from the machines. Dremel/rotary tool, air brush and air compressor I already have.. I have a total of five submarine hulls in my closet: a 32P XXIII, two Bronco XXIIIs, an RPMTech Seehund and a Revell VIIC (which I probably will only ever build for static display). Are any of them functional, NO... lol.

[Guest]

Re: Budget Lathes and Presses for WTC endcap constuction

I demonstrated the use of a live centre in the videos I posted on end cap construction. Basically you have two kinds of centres- live and dead (sounds cheerful doesn't it?).

A dead centre is a point that fits either into the tail stock or the driven shaft. When it goes in the tailstock it remains fixed, so the work spins on it. Clearly this will create friction, so a grease of some description will be used (tallow is common) to reduce that and prevent the centre from burning out.
This is fine for working on metals but not much good for plastics, as they will tend to melt. An alternative is to use a live centre, this has a ball race fitted inside so the centre spins freely in that, thus no grease needed, and it works as well with plastics as it does with metals.

They're far from essential- but a nice luxury. The Sherline machine comes with two dead centres as standard.

A four jaw is handy for machining non-round items e.g. if you want to machine a round spigot on the end of some square bar. You can't hold square items in a three jaw chuck. Another reason may be that you need to re-chuck something that has already been machined.

If you use a three jaw chuck to do this, it will be off centre, guaranteed. This is because chucks aren't 100% accurate even when minty fresh and new. With a four jaw you can adjust each jaw independently until the piece runs true, you need a dial test indicator to do this though.

Having said all that, the basic machine as it comes has enough bits and pieces to get you going, so you don't need to purchase these items upfront, although you may wish to get them further down the line- all depends on how far you get into it and what you want to machine.

To start with learn to centre tools accurately, turning stepped pieces with parallel diameters. Learn to turn between centres.

In the process of doing this, you could make some tools like mandrels, which will assist you in endcap construction.

[Guest]

Re: Budget Lathes and Presses for WTC endcap constuction

Regarding piston tanks. By and large they can be made from plastic. A plastic pipe with a plastic piston, the thread is just standard studding stock inexpensively available from hardware stores. The only custom machined metal part is the actually threaded spigot that fits on the gear for driving the shaft up and down. The material cost for these tanks is probably about £15-20 per tank, and you can build them for less if you have a decent scrap box to raid for bits and bobs like gears, microswitches etc.

The piston is sealed against the tube using standard o-rings. The trick is not to have too much compression of the o-ring, no more than 10% of the o-ring thickness, otherwise you introduce a lot of friction plus it's harder on the seal.

Silicone o-rings are softer than nitrile and a better choice. I have also experimented with Airzet rings, which are pneumatic seals sold by Freudenberg. These are only available in certain diameters, so offer less flexibility than o-rings, they're also fairly expensive and not easy to get hold of outside of Germany. They do give slightly lower levels of friction, but I'm not convinced they make a huge difference. The cup type seals used by Engel probably give the lowest friction, but they are rather bulky, and again difficult to find in the right size and expensive.

The real advantage with building your own tanks is that you can size it to your own requirements, rather than be dictated to by commercially available items. That allows more flexibility when choosing what boat to build.

I find the best tubing can be found from consumables that are thrown out. For smaller tanks it's difficult to beat the tubing used for silicone caulking. That has a totally smooth and accurate bore, making it a cinch to get a watertight seal. Larger diameter tubing can be a bit more of a challenge, as a lot of extruded pipe tends to be a bit wavy inside. Clear tubing e.g. polycarbonate and acrylic tends to be pretty good, but does pump up the cost a bit.

However going by the list of boats you mentioned the caulking tubes will be ideal.

[warpatroller]

Re: Budget Lathes and Presses for WTC endcap constuction

I picked up this Sherline 4000 Lathe, last Sunday, on the way home from visiting my mother. The lathe was about a 2.5 hour drive north of my home. My mother lives about an hour and 45 minutes north of me. The seller met me in a Sam's Club parking lot, close to where my mother lives, so it ended up being a convenient rendezvous.

He had a gasoline generator in his trunk, that we used to fire it up, so I could listen to, and watch the motor spin, to make sure that it ran good without any wobble or strange noises.

This is what I got for $400 :



Sherline 4000 with 2.5" 3-Jaw Chuck mounted on the headstock (made in California, not in China)

Including these extras]http://www.subcommittee.com/forum/icon_rolleyes.gif[/img] The only keys I currently have that fit them are the ones that are clamped down in the chucks.. Didn't realize I wouldn't be able to loosen them by hand, until I got the lathe home, oh well..

This lathe was bought new by an old man who passed away before he really ever got a chance to use it. The seller was a machinist, who bought it at an estate sale along with some other items. He said it was too small for him and he really didn't have a use for it.

To buy everything in the photo new, would cost at least a minimum of $800. So, it wasn't too bad of a deal..

Another step made, in preparation, for the adventure of getting a sub running while submerged in the water (which has now become a bucket list item for me).