How to make flashlight bodies?

I know a lathe can work the outter surface to produce grooves and changes in OD, but how do people hollow out solid bar stock? And how are textures such as knurling put on? Just wondering as I'd eventually like to be able to make my own bodies instead of using host lights and would like to know what is needed aside from a lathe (which I don't have either).
Thanks.
J.

I'm not a machinist, but I believe what is used is a mill, and usually CNC.

oops.

A lathe is all you need to make light bodies,

You can start from solid bar stock, or tubing,
and bore it out as you like,

There also knurling tools that attach to the lathe,
that allow you to add knurling to the OD of the light.
though I have not seen ones to knurl the ID of anything.

You can even do you own threading on many lathes.
They have differnt gear ratios for differnt threading.

A Mill is generally used to do NONE Round shapes,
such as cutting grooves down the length of the light,
or making a tail of an Arc AAA, or FireFly. etc.

~John

I wasn't sure, but I knew if I was wrong we'd get the right answer soon.

Other than what John said, all I can add is that if you do decide to take the plunge, don't skimp on your tooling. Get a decent set of indexable tools and GOOD drills. A cheap set of drills can make drilling out a body a nightmare.

how do people hollow out solid bar stock? And how are textures such as knurling put on?

Click to expand...

Hollowing bar stock is simple. Drill a hole in it axially and then bore it to desired diameter.

The initial hole is drilled with a drill bit that is held in a chuck that "points" directly at the portion of the lathe that spins. These are called tailstock and headstock, respectively, and the centers of each must precisely match. You mount the work in the headstock and mount the drill chuck in the tailstock. The tailstock has a crank handle so you can advance the drill bit into the work. (Deep drilling presents other problems, such as the limitation of the tailstock's travel, flexibility of the lathe and the workpiece etc etc etc, but that's for another forum.)

To bore the hole, a boring bar is mounted in the cross slide. The cross slide simply travels the length of the lathe bed (left and right) and allows you to advance a cutter into the workpiece (back and forth). The boring bar is just a bar with a cutter on the end, and the cross slide allows you to move the cutter into and along the ID of the workpiece.

Knurling is classically applied by (of all things) a knurling tool. The knurling tool has two carbide wheels on it each with opposite halves of the knurl pattern. The knurl wheels are advanced into the turning workpiece and the pattern is impressioned, not cut. Knurling is a difficult operation because the OD of the workpiece has to be one of a range of specific diameters in order for the knurl pattern to line up during each revolution of the workpiece. Knurling frustrates me so that I usually mount the workpiece to a spin index and engrave the pattern on my mill!!

If you want to get serious about home machine work, get a copy of "How To Run A Lathe." It was published by South Bend in the 1940s but ALL of the data is 100% applicable to modern machines. It's like a $6 book that's available at Amazon.

Last but not least, since most hobbiest do not own very powerful machines, try to buy stock that is relatively close in size (and ideally, hollow) to what you want to build. There is a very close relationship between the HP of your tools, and time to remove material.

Of course, you can also just draw it up, and take it to a machine shop. While this can be expensive, it is sometimes cheaper than buying all of the required tools.

Thanks guys! Great info! I really appreciate the quick and detailed responses. I was looking to get a small table-top lathe. I found some on the internet a couple of years ago, but never got one or looked much into them. I doubt they're very powerful, but it might be a start and this is still a hobby only. I'll pick up that book scott.cr mentioned also. I never knew a lathe could drill and bore. Thanks everyone!

scott.cr said:

If you want to get serious about home machine work, get a copy of "How To Run A Lathe." It was published by South Bend in the 1940s but ALL of the data is 100% applicable to modern machines. It's like a $6 book that's available at Amazon.

Click to expand...

I tried to find it on Amazon (and Barnes and Noble) but it is not available

If you or somebody has an extra copy available, please PM me with details

Will

If you are going to get into a lathe, but want to keep it small, I'd go with one of the imports. They are fairly well built and reasonably accurate. I'd go with a 7X12, at the least. The 7X10 is too short to comfortably bore anything longer than a single 123 cell body. These lathe also have automatic feed and are able to cut threads.

wquiles said:

I tried to find it on Amazon (and Barnes and Noble) but it is not available

If you or somebody has an extra copy available, please PM me with details

Will

Click to expand...

Will, try this search link (results from the search I did for you -wasn't sure of the exact ISBN, so I left the main search results for you to sort through - $10-35 or so): addall.com

That's through whom I get all my books - cheapest prices I've found.

I agree with Chop on the lathe size. I have a 7x10 and daylight goes away fast with anything longer than a 2D tube. (Even the 2D tubes need some dorking with to do a full-length bore.)

If you have the $ I would go for a 9x20 from Grizzly. Horrible Freight's stuff is iffy. I wouldn't buy from them unless you can test the lathe for accuracy first.

If you are half way handy, you may be able to pick up a Harbor Freight 7X10 on sale and then pickup a 14" bed for it and still come out less than the micromark would cost you. Go to www.mini-lathe.com and check out the different models. You can also checkout www.littlemachineshop.com to see what's available.

greenLED said:

Will, try this search link (results from the search I did for you -wasn't sure of the exact ISBN, so I left the main search results for you to sort through - $10-35 or so): addall.com

That's through whom I get all my books - cheapest prices I've found.

Click to expand...

Thanks. I found one used one (suposedly) in good shape . I should get it on a week or so

Will

Thanks guys again. Great info. I appreciate the links as I know I would have no idea where to start looking and would just do random google searches.

What are your opinions on the following models:

Grizzly 7x12
Micro-Mark 7x14
Cummins Industrial 7x12

The Cummins is the lowest priced, but considering they're all in the $400-$600 range (Grizzly is the priciest), I'd rather pay for quality and precision differences than worry about the price. I didn't know these were so cheap. I forgot the site I looked at a couple of years ago, but recall they were just under $1000 starting with most models just over $1000. These are considerably lower priced.

It's been a little while since I bought my lathes, but IIRC, of the three, the MicroMark is the Rolls Royce (if there is a RR of mini lathes). Although all of them are produced in the same place, it appears that MicroMark goes an extra step. I think the MM has a 1/2 hp motor, rather than 1/3 hp, and everything is setup for true inch measurements. As far as I know, all of the others are "adapted" to work on the inch scale, which really isn't accurate.

I have a Homier 7X12 and it's pretty nice. I paid $350 for it shipped. Unfortunately, they don't sell them any longer.

In the end though, they will all need to be adjusted at some time, if not out of the box. One of those sites that I gave you links to tells you how to do it. All of these machines are essentially the same machine, except for the color. Just get the one that comes with the best customer service and the biggest bang for the buck.

I do have to admit, at this point, however, that if I had it to do all over again, I'd go with the Micro Mark for the longer bed and the stronger motor. The extra bed space is nice. Not only will it allow you to turn longer things, but it will also allow you to more comfortably use a 5" three jaw chuck. This was the best upgrade that I did to my lathe.

With this chuck, I can actually "chuck" a collet fixture for 5C collets and use the 5C collets in my mini lathe. I can also chuck 2" diameter stock and have enough bite with the chuck to be able to work with it and part stock that thick.

No prob, Will. So far, even the "used" books I've gotten through them have been brand-new. Hope you have the same experience.