slug manufacturer???

[Possum]

I'm looking for a company to make slugs, anyone have any recent experience with a company that is helpful and does a good job? Good prices?

[Spence]

Sounds like you've given up Dave. I would persevere if I were you. Call into a local machine shop and ask them how they would go about it.

[Possum]

too slow....

Well I didn't give up, I can cut decent slugs, but still gotta cut off the pip, then plate them, its really slow doing it this way. It does give me the opportunity to try other alloys without paying someone to do it. Skinnying down a quarter inch rod is definitely out of the equation, took hours to cut it down then cut slugs out of that, crazy amount of time, had no idea. Still I like the lathe and it sure does take some mastery. The cutting blade wants to jam in there and oil doesn't help, little stuff like that. I suspect the steel I'm cutting isn't machine friendly but its the right stuff to use. The lower carbon stuff seems harder to cut in some ways, more grabby. I dropped the price on my Platinums, it was too high and very few were ordering them, now they are starting to buy, so better to figure out exactly the slugs I want them get them made. I'll still cut my own keepers, they are pretty easy to make.

[DoctorX]

Sent you separate e-mail

Dave,

Please check your inbox. I sent e-mail to 'opendoor.com'.

Thanks,

Doctor X

[Joe Gwinn]

The cutting blade wants to jam in there and oil doesn't help, little stuff like that. I suspect the steel I'm cutting isn't machine friendly but its the right stuff to use. The lower carbon stuff seems harder to cut in some ways, more grabby.

This sounds like the cutting edge of the blade is above the axis of rotation of the workpiece. Although not visible to the eye, the blade bends downward under the force of cutting. If the blade is above the axis of rotation, this bending down causes the cutting edge to dig deeper, which increases the downward force, which increases the bending, which causes the edge to dig even deeper, etc. It's a classic way to break a tool. Nor is oil any help - the problem is mechanical.

Try lowering the tool so it's ever so slightly below the axis of rotation.

More generally, imagine how things would distort and move were they made of rubber. Steel does the same, only the motions are smaller and the forces are larger.

[Possum]

...........

I'm real careful to keep it at a hair just below center, I get a small pip on the rod when its cut and have to run it back over to cut that off. Its binding on the left and right side of the blade despite being real careful to have it squared up. I suspect I need to use a steeper angle of the cutting blade, after all this is a half inch blade made to cut large diamter stock. I have the Micromark mini cutoff blade which cuts better but the holder is crap and it slips in the holder....

[black_labb]

I'm real careful to keep it at a hair just below center, I get a small pip on the rod when its cut and have to run it back over to cut that off. Its binding on the left and right side of the blade despite being real careful to have it squared up. I suspect I need to use a steeper angle of the cutting blade, after all this is a half inch blade made to cut large diamter stock. I have the Micromark mini cutoff blade which cuts better but the holder is crap and it slips in the holder....

you cant keep it too low either, otherwise the workpiece tries to climb ontop of the cutting bit, making it dig in further. i am an engineering student and had a subject called manufacturing engineering where we learnt all about different shop tools and other methods of manufacturing, and they said that a lathe should be cutting a hair above the centre. i understand the logic of cutting a tiny bit under the centre, but if you think of it, the cutting tool is more rigid than the material, so the material can more easily bend out of position. i remember the lecturer saying that using it just above the centre helps get a better finish too. i also have some experience turning things, ive made a couple bike hubs and a couple other small things.

why not try raising the cutting bit to just over the centre and see if that helps at all, if not just go back to how you were doing it.

[Possum]

...........

I just wish there was a way to cut the piece and have the nib on the piece falling off be cut off too. I sharpened the tool and accidentally had it angled slightly towards the cut off piece and even though its the first part of the blade to start cutting it still has a nib when it falls off. I think the screw manufacturers use a rotary carbide or diamond type of cutter to cut stuff like that, I saw a screw cut off cutter on ebay that was like that...

[David King]

Dave I suspect that there is still a lot of play in your lathe. Squirt some way oil on all the way surfaces until everything is heavily coated then grab the cutter and start pushing it around. Wherever there is play you will see the oil moving around along the edge where the way surfaces meet. Tighten the gibs until the oil doesn't move. You may have to disassemble the cross slide and flatten things until they fit together correctly using a granite surface plate, prussian blue, a scraper and a machinist's straight edge/ level. This is called "scraping-in" a way and it's an art form that takes years to learn but you can probably muck your way into a half-assed job to get this lathe to work well enough for you. Having a professional do it will cost you many times what you paid for this lathe and i doubt a self respecting pro would even touch this job.

I'll email you the guy I know that has a screw machine with open time who also plays guitar and used to be a roady. That's the sort of machinist you are looking for. I'll bet he could do these for under .10 per slug in quantity.

[jonson]

Dave is probably right in a certain amount Possum that there is some play in your machine. I end up on my lathe at least once a week making replacement parts and no part off problems but what I also suspect is that the sides of the cut off tool you are using have been left parallel and you are rubbing the slug off before it is finished cutting. Try grinding back a bit as in my scruffy drawing and you will get less pressure on the tool and will be able to go a bit finer in your cut. Stuck my nose in my library this morning and dug out an old book on lathe Q and Answers and scaned the section on tooling which although writen in 1972 still stands to this day. You will find a file from me in your e-mail inbox with lots of pretty picks and lots of real info as I would hate to see you give up at this stage. If you can get that machine working to your advantage then that is exactly what it will be.

[David King]

Dave,
You will always get a slight center boss/ nib on the parts, there is no way around that. You just need to sand/file that off by hand or put it back in the chuck and face it off in a second operation (or live with it).

You might try a brass tube of the correct id in the tailstock chuck to hold the part being cut off. you could even use it to set the-cut off length but you'd probably need a glove to pull each hot piece out of the tube... It's the same idea as the rotating tailstock chuck but w/o the extra expense or added time to tighten and loosen the dumb chuck.

[Joe Gwinn]

I'm real careful to keep it at a hair just below center, I get a small pip on the rod when its cut and have to run it back over to cut that off. It's binding on the left and right side of the blade despite being real careful to have it squared up. I suspect I need to use a steeper angle of the cutting blade, after all this is a half inch blade made to cut large diameter stock.

The other thing that can happen is that the blade deflects to one side or the other. Making the sides steeper (and sharper) should help.

I have the Micromark mini cutoff blade which cuts better but the holder is crap and it slips in the holder....

Given the size, you should be able to find a better holder. What does Little Machine Shop offer?

Or, you can put the pip-tailed slugs in a rock-polishing tumbler with some deburring media (ceramic stones) and grind everything smooth.

[Possum]

...........

Believe me I went through everything in the lathe and adjusted out the play everywhere so its pretty solid at this point. There may have been some play in the post too, haven't tried the new one yet. I just got the replacement quick change post today and it works great!

Also got a second carriage stop to to have two stops for each end of the movement.

I'm using the holder for the half inch blade from LMS and its good and solid, the little one from Micromark would work great if they made a decent holder for it, one screw doesn't cut it and it slips real easy, not recommended though the smaller blades cuts quicker and cleaner, maybe I can figure out a way to hold it otherwise.

Dave, I'm still looking around, would rather find someone who has made these before so I don't have to jump through alot of hoops trying to get them to understand what the heck these are. Ten cents is actually a bit high.

[Possum]

better....

well I cut a slug with the new post and its much more solid, also cut the angle of the blade a little more steep going into the cut and that seems to be helping plus cutting slower, everything is real solid now, great!

[KinkyWinks]

I've got plenty of 3/16 X 1/2 chrome slugs. What size are you trying to make?