Lathe questions

[Jeff]

I was watching a youtube clip the other day and saw one with a CNC where they used compressed air as a coolant. I was using a friends lathe recently taking a finishing cut and the swarf was building up, so grabbed an air hose and blew onto the tool. This removed the swarf building up on the tip which looked like it was scratching the finish on the part.

Is this bad? The coolant pump on said friends lathe was broken so I had not been using coolant anyway. Does swarf buildup affect surface finish?

https://www.aulro.com/afvb/images/imported/2014/01/709.jpg (http://s1336.photobucket.com/user/Jeff_8/media/Machining/110120142091_zpsf58af5b2.jpg.html)

https://www.aulro.com/afvb/images/imported/2014/01/710.jpg (http://s1336.photobucket.com/user/Jeff_8/media/Machining/120120142117_zpsc6384197.jpg.html)

Jeff

:rocket:

[Blknight.aus]

depends on how and what you're cutting.

simple answer,

Yes.

[Bigbjorn]

Sometimes you will get a build up of swarf welding onto the tip, particularly aluminium workpieces. Yes, it will affect finish. An oil can or spray bottle of kerosene squirted onto the tip from time to time usually stops build-up. Don't set the swarf tray on fire! I have also seen plenty of machinists use a scriber to pick at the build-up whilst the machine is running. Please don't do this unless you are in a suit or armour, and likewise, with long chipping material, don't try to remove a birds nest of long swarf from around the job or chuck whilst the machine is running. Good way to lose a finger or two or get grabbed and dragged in to the machine.

[Jeff]

I am mostly turning 5000 or 7000 series aluminium.

I sometimes pull the birds nest of swarf away with a tent peg, but shudder at the thought of using my fingers.:eek:

A friend often turns magnesium as he makes Manx Norton replica brake drums, and often has swarf fires under his lathe.

Jeff

:rocket:

[Hall]

Remember as a apprentice the other apprentice did some serious damage to a hand. Dropped the swarf hook into the swarf on the floor next to the head stock. Went to retrieve it and the swarf pick up around the chuck. I had to clean up. You can get spray cans of cutting fluids. These are better as they not flammable. Always found tool steel best for non ferrous metals as you can get a much sharper edge than carbide.
Cheers Hall

[marko66]

Hi All


Apparently the waste from bio diesel is also a good lubricant


Regards Mark

[snowbound]

Hi All


Apparently the waste from bio diesel is also a good lubricant


Regards Mark

Don't use it in the bedroom! :wasntme:

[Jeff]

I bolted some wheels together and had to take a skim off the edges. Initially I used what I thought was slow speed and a carbide tip, but it chattered like a very chattery thing, so I changed to HSS and ran it about 25 rpm and it cut beautifully.

https://www.aulro.com/afvb/images/imported/2014/01/203.jpg (http://s1336.photobucket.com/user/Jeff_8/media/Machining/190120142153_zps22397423.jpg.html)

https://www.aulro.com/afvb/images/imported/2014/01/204.jpg (http://s1336.photobucket.com/user/Jeff_8/media/Machining/190120142154_zps6b5d2872.jpg.html)

Jeff

:rocket:

[Jeff]

More questions. I may be able to pick up a lathe, but it has been neglected and abandoned (indoors) for a few years. The bed, cross slide and chuck have quite a bit of surface rust on them and some gears are missing from the feed. I have not run it, as the oil level was low, but it has had little use and was looked after before being 'abandoned' when the tradesmen were moved elsewhere.

How rusty is too rusty?

Are gears and other bits available or interchangeable between brands?

Jeff

:rocket:

[JDNSW]

More questions. I may be able to pick up a lathe, but it has been neglected and abandoned (indoors) for a few years. The bed, cross slide and chuck have quite a bit of surface rust on them and some gears are missing from the feed. I have not run it, as the oil level was low, but it has had little use and was looked after before being 'abandoned' when the tradesmen were moved elsewhere.

How rusty is too rusty?

How long is a piece of string? As long as the precision mating surfaces are not pitted enough that they do not slide smoothly, should be OK after the rust is removed. Be very careful removing rust to not remove any metal. Other than on mating surfaces, the rust will only be cosmetic.

Are gears and other bits available or interchangeable between brands?

Jeff

:rocket:

Whether bits are available new will depend on the brand. If it is a popular brand, ebay is a likely source. Parts are unlikely to be interchangeable unless one brand is a copy of another (which happens quite a bit, but knowing this is not likely to be easy unless you have an informant who is experienced on both!)

Hope this helps,

John

[Blknight.aus]

Almost reminds me of a conversation I had with someone who just bought a vertical drill mill with a set of gear cutters but was missing one of the the drive gears for the electric auto feeder for the deck......

Id suggest if you can find a gear cutting jig thats of appropriate size that you look at your lathe as tho its a horizontal drill mill with a somewhat oversized chuck piece...

as one of the old school guys told us when I was learning the basics of swarfery.

"its easy to comment that now that we have the thread turning lathe it becomes possible to manufacture the thread turning lathe. But remember boys somewhere someone has had to solve the same or near enough to the same problem as you face, you just have to realize that just because you dont have all the modern easy gear to do it doesnt mean it cant be done."

he would then over the months of the course (and I wish I had gotten to spend time there other than the basic intro weeks) would produce a about an 3 foot long peice of art that was a fully decked out and working thread turning lathe that he would give to the ducks of the course. Every part of the lathe was used as a demonstration for some part of swarfery.

[POD]

I bought a big old Asian lathe (actually my 50th birthday gift from my wife, but I did the choosing and getting) that had some of the gear train missing, most significantly the 127-tooth gear that enables metric thread cutting on an imperial machine. It's been impossible to find the right gears, and I got a quote of around $1300 from a gear-cutting mob to manufacture the 4 gears to complete the set (tell 'em they're dreaming...). I plan to cut the gears myself, after some online research I've found that this can be done in the lathe with some fairly complicated setting up. I posted some questions about casting gear blanks in an online metalwork forum, and a bloke in the U.S. has very kindly undertaken to cast them for me in his backyard foundry. Just hope I don't stuff the blanks with my first attempts at cutting gears.
The common / popular models of lathes, particularly the American machines, seem to be reasonably easy to find parts for, but with the more obscure machines you're pretty much on your own. My crossfeed screw is badly worn, I've had to make a replacement myself, next step is to make the crossfeed nut to suit. Fortunately, a lathe is a great tool for making lathe parts.

[POD]

Id suggest if you can find a gear cutting jig thats of appropriate size that you look at your lathe as tho its a horizontal drill mill with a somewhat oversized chuck piece...




Dave, I'd be interested to know more about the 'gear cutting jig' you refer to, apart from expensive dividing heads, I've only seen shop-made setups in my web searching, and even then it's nearly all woodwork stuff for clock making.

[Bigbjorn]

One off gear cutting by a hobbyist is easiest done with a horizontal or universal milling machine. No need to cast blanks. Machine them from heavy plate or bar. If you don't have one or can't borrow time on a milling machine, 'phone around the TAFE colleges to find if one still has a hobby or certificate course in metal machining.

[mick88]

Tool height and cutting speeds are important.
For external turning make sure your tool is not too high as it may be contacting the work piece slightly below the cutting edge!
Also make sure your revs are pretty close to giving you the correct cutting speed for the diameter of your work and the type of material it is made from!
Chatter should be minimal or non existant if all those can be achieved, however a rubber band cut from a car tube and stretched over the workpiece can help. My lathe runs a bit too fast for maching 11" brake drums, so a lacky band stretched around the outside does the trick.
Good luck and as others have said, wear safety glasses and keep your fingers away from that swarf, it has no mercy!



Cheers, Mick.

[Bigbjorn]

I bought a big old Asian lathe (actually my 50th birthday gift from my wife, but I did the choosing and getting) that had some of the gear train missing, most significantly the 127-tooth gear that enables metric thread cutting on an imperial machine. It's been impossible to find the right gears, and I got a quote of around $1300 from a gear-cutting mob to manufacture the 4 gears to complete the set (tell 'em they're dreaming...). I plan to cut the gears myself, after some online research I've found that this can be done in the lathe with some fairly complicated setting up. I posted some questions about casting gear blanks in an online metalwork forum, and a bloke in the U.S. has very kindly undertaken to cast them for me in his backyard foundry. Just hope I don't stuff the blanks with my first attempts at cutting gears.
The common / popular models of lathes, particularly the American machines, seem to be reasonably easy to find parts for, but with the more obscure machines you're pretty much on your own. My crossfeed screw is badly worn, I've had to make a replacement myself, next step is to make the crossfeed nut to suit. Fortunately, a lathe is a great tool for making lathe parts.

It is not uncommon when inspecting old lathes offered for sale to find some of the change gears missing particularly the 127 tooth gear. Many shops never worked in metric particularly screw cutting. If the lathe is still in the shop go have a look in the tool store. Usual practice is for the commonly used gears to be in the chip tray or on the headstock and the seldom used ones left in the store. I have known it when liquidation auctions are scheduled and the shop is cleaned out and packed up for sale for all extraneous unidentified pieces to be thrown out or put on a pallet for sale as a mixed lot of supplies. The missing gears can sometimes be found in the scrap or in a mixed lot. Sometimes the full set of gears are hidden so one of the staff or a mate can buy the lathe cheaply. I have seen this at a TAFE College auction.

[Jeff]

The lathe is a Nuttall, similar to the one in the pics. Interesting to read Brian's comments, I will need to look around the workshop if I am able for the missing bits.

Jeff

:rocket:

[POD]

It is not uncommon when inspecting old lathes offered for sale to find some of the change gears missing particularly the 127 tooth gear. Many shops never worked in metric particularly screw cutting. If the lathe is still in the shop go have a look in the tool store. Usual practice is for the commonly used gears to be in the chip tray or on the headstock and the seldom used ones left in the store. I have known it when liquidation auctions are scheduled and the shop is cleaned out and packed up for sale for all extraneous unidentified pieces to be thrown out or put on a pallet for sale as a mixed lot of supplies. The missing gears can sometimes be found in the scrap or in a mixed lot. Sometimes the full set of gears are hidden so one of the staff or a mate can buy the lathe cheaply. I have seen this at a TAFE College auction.

Thanks Brian, I made extensive efforts to locate the missing gears, plus travelling steady; I made a trip from Bermagui (where we were holidaying) to Sydney to the factory that originally had the machine, after talking with the foreman who reckoned the parts might be on a pallet somewhere. Drove home empty-handed and very disappointed. I've since fabricated a travelling steady (follow rest), making the missing gears myself seemed the only option left.
It was suggested to me to use plate or bar stock to cut blanks from, but these gears are 1" thick and the 127-tooth gear is 10.75" in diameter, I wasn't able to source suitable stock.

Sorry Jeff for the semi-hijack. I've seen parts for Nuttal lathes occasionally on eBay. Hopefully the workshop has your parts out the back somewhere, I was unlucky in that the company had moved premises a few years prior, and chucked everything out in the move.

[Ancient Mariner]

Old flywheels make useful stock .Holden red motor is about 11" and thick enough just bolt in appropriate centre They are not SG iron but as good as the old flatbed lathes used for change wheels:)

AM

[Boony73]

This is a handy resource for information on lathes

Lathes (http://www.lathes.co.uk/)

This company advertises that they supply Nuttall spare parts

B & D Machining Pty Ltd | Precision Machining & Prototype Manufacturer (http://www.bdmachining.com.au/)

[Jeff]

I thought I would drag up an old thread rather than start a new one. The lathe I was hoping to obtain was scrapped, much to my disgust although I am still searching for one at a good price.

Until I get one I will have to make do with my small lathe, as the friend who allowed me to use his earlier in the thread has now put it into storage awaiting a move interstate.

My lathe has a bad problem with chatter particularly when parting or facing probably due to its cheapness and small size. Would adding a quick change tool holder reduce this? They seem much more solid looking and easier to height adjust. Would attaching the lathe more firmly to the bench reduce chatter as well? It is sitting on a bench made of 4 x 2 timber, it came with a cabinet, but the bench makes it a better height.

Jeff

:rocket:

[Ancient Mariner]

Jeff
A quick change won't help reduce chatter some things which might help. Reduce speed and or increase feed When facing if you have locks lock the saddle and the top slide same with parting also keep the radius of your cutting tool as small as possible while still keeping a reasonable finnish . Keep your cutting tool close to the holder and take heart in the fact that even in a top of the line lathe you will get chatter unless you can properly support the job:(

Noel