Tap 5/8" x 8 TPI Left Hand ACME

[Gunor]

I don't know how smart i am, but I bought a 70's vintage Jet 10x24 lathe. Nice heavy cast iron.

Decent price (cheap and local) - but needs a little work. Already installing a 1 HP 3 Phase VFD setup - wife had one in her shop.

Cross slide nut - is in rough shape. Brass...

I have check the internet for taps - I found one in the UK for 30 pounds (just sent an email for more details). US tool suppliers - $12x for a tandem roughing/finish tap.

Ebay - has a guy that makes the correct pitch for South Bend - so I sent him an email...

I can find round brass nuts, but I would have to solder it to more brass to mount.

Just wondering if someone has that tap or...

Ideally - I like to have 2 nuts made out of rectangle stock (1.5" long x 1.x" high x 1.x" wide) - D/T

Thanks

Geoff in Oregon

[bearcove]

Make one on the lathe?

[fg-machine]

30 pounds comes to what a bit over $45 . with shipping you will be at around $70 give or take .
if it is a good English made tap it will be well worth the money . if you are buying a Chinese or Indian made tap from a British guy . not such a good deal .

i would advise against using one of the cheap Chinese taps , you want nice as close to perfect threads as you can get for your cross feed nut .

[Gunor]

Lathe - making - not even close to being that skilled. Nor the time/energy - still working, teenager's sports/activities, and etc. Probably make one in the future - but time...and i have some small lathe projects that i need to get done...annealing machine, barrel vise bushings for my 1903/M-1 project, 1903 bolt lapping/bolt face bushing. Even thought of putting a short 300 BO barrel on a little bity Sako...

Hopefully I'll get some details on the UK option.

[bangerjim]

A metal lathe is the only tool that can make most parts for itself! I have done it many times. And with a milling attachment, even mill smaller parts, even with old sloppy fitting nuts and threads and misc stuff. Use those to make new ones and....BINGO....a like-new old lathe!

As long as the main parts are OK - head & tail stock, cross and compound feeds, apron, gearing - you can make a lot of the parts for it on itself! An excellent learning experience in good old " Yankee Ingenuity" and machine shop techniques!

Good luck in you quest.

bangerjim

[Frank46]

Silly question but here goes. Why not contact Jet and see if the half nuts are available as spare or replacement parts?. Try Enco, Travers tools or MSC and see if they have the tap you need. Just a couple suggestions. Frank

[Gunor]

Jet, no longer has spares for this machine. I got some insight reading all the different forums on these machines and vintage. Jet basically job shopped the lathe, probably to the low bidder. So these early machines had real difference between them.

So far looking for taps in the US - still over $100.

[SOFMatchstaff]

Gunor, go to this company. they have what you need. I got the parts to do the cross slide repair for a LeBlond that
was sloppy.

http://www.greenbaymfgco.com/ACME-nuts.php

[Ballistics in Scotland]

We've heard nothing unsmart about it so far. Here is a firm that has one quite a bit cheaper - unless it is the same one, and the £30 includes postage. They buy from various countries, but it is HSS and I have done a good deal of business with them over the years, and have found them very reliable and helpful.

They don't list this item on eBay at the moment, where they are rdg355, but they have over 237,000 transactions there, with 100% positive feedback, which isn't easy. A few years ago they bought the carcass of the Myford lathe company, and are doing a pretty good job of obtaining and supplying parts. If you have to ask technical questions, Chris is not one to take offence or say he doesn't know what is in the box.

They are in a lovely mountain valley in Yorkshire which has been badly affected by floods recently, but it is unlikely to affect deliveries by much.

http://www.rdgtools.co.uk/cgi-bin/sh000001.pl?WD=tap%20acme&PN=ACME%2dTAP%2d5%2d8%2d%2dX%2d8%2dTPI%2dHSS%2d%2d LEFT%2dHAND%2d%2d994093458%2ehtml#SID=34

http://www.itv.com/news/2016-01-04/mytholmroyd-floods-towns-businesses-battle-to-clean-up-after-boxing-day-deluge/

[Gunor]

Mr. Scotland,

Thanks. RDG Tools has a tap for 15 (British pound). "1 SECOND CUT TAP” trying to figure that out in the description - Finishing Tap? For $22 USD - easy to try - even if India or China stuff.

I also find they have those 'oiler buttons' - everywhere else those are metric size - but RDG has them in imperial. My Jet Lathe, weird like, has imperial screws (bolts and cap screws) - so I need to check the diameter of the oilers to get the right size.

http://www.tracytools.com/taps-and-dies

They did respond to my email:

"Thanks for the enquiry, they are single pass taper lead taps which are 160mm o/all length with 100mm of thread, they are finishing taps that product a
full thread form."

[Ballistics in Scotland]

That sounds about right. A second cut tap just means that the taper or chamfer at the front end is longer than for a bottoming tap but less than a taper tap. It will be a shade harder to start the tap in the hole, but you can make your nut longer and the hole chamfered at the start, and shorten it afterwards when you have a threaded hole. The finished thread won't be tapered.

That reply does eliminate a couple of pitfalls with Acme threads. Sometimes the taps are made with a roughing tap which is slightly undersize, and a finishing tap which produces the smooth thread of the proper size. The latter alone should be fine in brass or bronze. Also there is a series of stub Acme threads, which have only part of the height.

Some threads are more Imperial than others. American threads in inches are often so called. But there are also the British Standard Whitworth and British Standard Fine, which have pitches close to the American UNC and UNF respectively, but have 55 degree V-threads instead of 60 degrees, and rounded crests instead of flat.

It is unlikely that anything but a very old American lathe indeed would use these for most purposes. They have been almost entirely replaced by metric in the UK for new work. It is just possible, though, that an oiler might use the British Standard Pipe thread (probably the tapered version) to make an oiltight joint, as this is still quite common in the unImperialized regions of the world. But they are very close to the American versions.

https://en.wikipedia.org/wiki/Threaded_pipe

[Gunor]

So I am think I am good on buying the UK tap - cannot be hurt too much. Mr. Scotland, explained enough about the tap type - that i am fairly confident that it will work with my brass/bronze application. I'll see if the ebay guy comes back with an answer on his south bend parts.

Button Oilers: http://www.rdgtools.co.uk/cgi-bin/sh000001.pl?WD=oiler&PN=20-X-3-16--Button-Oilers-2218%2ehtml#SID=246

This Jet, and I am no expert - is sturdy heavily cast iron for it size. Crude in many ways - but not too bad. The lathe is from Taiwan, chuck is Japanese, and the drill chuck is 'West German'.

[akajun]

Enco, item number 505-6804 is a single cut tap, 78$ , #319 5427 is a double cut tap, 319-5427, both are made in usa taps, class 2g threads.
ON a lathe crossfeed nut, I would want good class threads, Im betting that the UK tap you listed is chinese.
other option is to buy a bronze nut pr threaded, item # 328-2472 and modify it to fit your machine by brazing/ soldering.

Also look up making what is called an "evanut" from delrin.

You dont want to single point a 5/8 internal acme thread, that will give a seasoned machinist fits.

[Cap'n Morgan]

Why change the nut at all? As long as the slide ways are free of play, a little end play in the spindle doesn't matter much. The accuracy of the cross slide is determined by the lead screw - not the lead nut. I have worked on lathes with a quarter of turn backlash in the hand wheel without problems.

If necessary I suppose you could fix the old nut by mounting an extra nut behind it with a couple of conical spring washers between the two. Properly adjusted it would take up any end play (and compensate for an unevenly worn spindle as well) but it would reduce the slide travel length a little.

[big bore 99]

Jet is a pretty decent lathe for the money. I've been a tool and die maker the last 48 years with 25 yrs in my own small shop. A lot of the import machine tools are made in the same factories with different brand names. It shouldn't be too hard to find a replacement lead screw and nut. I've single pointed LH threads a few times and it is a pain the first couple of times. Sorry I can't help any more than that. I sold all my toys off a couple yrs ago. I miss it once in awhile. but mostly glad to be retired.

[W.R.Buchanan]

Why not just buy the part and replace it? Probably be all of $20.

You are not going to like the big Acme Tap. They are major PITB'S and the results you think you are going to get,,, are not going to be what you want. Also you will be using it exactly once.

Why would you want to do this?

Just buy the part from Jet. Then you know it will work.

Randy

[Gunor]

Jet dosen't make the part anymore. Also those early jet lathes - there is probably 10 different manufacturers that made the 10x24 (maybe not that many - but little standardization.) My spindle nose is 1.9x" x 8 TPI - go figure that.

Button oilers - the little steel ball 'oiler's" - If you need them - inch are available at McMaster-Carr. Metric size - ebay. I got my inch oilers from Amazon last night - Quick change box (has 6 - all toast) - 1/4" fits perfect. Tail stock - *** - I will have to epoxy it in - that loose.

Still waiting for tap and 1" round brass for cross slide nut. Might hate myself for the tap it get (2G vs 4G) and not a rough/finish type.....

1 HP 3 PH motor came in - need to make a new mount plate (extension) to get everything lined up.

Got the control wiring figured out - on/off, forward/rev - have fuse holder....VFD hopefully works - it was on the back shelf...

My status...Kids, and their sports, and their music - youngest is on the state honor band....

[Bent Ramrod]

How is your cross slide screw? If the nut is almost gone, typically the screw will be worn noticeably in the areas it was adjusted most. The threads will be thin and the screw will have a "swamped" look. A new nut threaded by a standard size tap will be pretty loose on a worn screw, although, of course, it will move accurately in one direction once the backlash is taken up.

The crossfeed nut on my 10" Atlas lathe was, literally, hanging on by a thread. I ground an Acme shape on a 1/8" high speed steel blank, cut it off with a grinding wheel and fitted it into a piece of 1/4" rod. Several tension filled evenings later, I had a left hand threaded hole in a piece of brass, somewhat undersized from normal, but which fit the worn crossfeed screw very well. In threading the nut, I clamped the crossfeed apron down in the middle and made adjustments with the compound feed only.

I wasn't that skilled, either, and still am not. I read the instructions, set the gears, checked, rechecked and went slowly enough so that any potential disasters could be headed off early. The crossfeed screw was the gauge I used to check progress.

Better to practice on a cheap piece of brass than an expensive Sako rebarrel project;-).

[Gunor]

Cross slide screw looks ok. Some reason the screw has about 0.050 (+) round out at the tip - so it was binding a lot. I rolled the screw portion on my granfather's cast iron surface plate (layout?) - screw portion seems straight. The shaft is two pieces - screw and handle side. I think the PO dropped the assembly (rear thrust bearing/housing and bent the shaft where they join...I need to bend it back at that point.

Nut - hangs on by a single sock screw - #12 or so. A single hole thru the top of the cross slide - and no boss on the 'totally' round (1" d) brass nut. So I think with the bent screw and a loose screw - it really weared the nut out.

Atlas - years ago, I had an atlas and my buddy had one too - we went on together on a tap....

Too much like a blog....

[fg-machine]

if the screw itself is bent it really isn't a big deal , you can buy acme threaded rod from enco very cheaply and replace it without a lot of bother .
and of course if the unthreaded piece is bent , just cobble the machine back together and make a new one .

you can make parts on a lathe without a working lead screw on any axis , it just takes time and a bit of effort . if you can make the chuck spin and hold the work you can fix it .

it is very important for lead screws on all axis to be as straight as possible . bent lead screws can drive you crazy with surface finish .

[W.R.Buchanan]

Gunor having rebuilt machines in my shop for 30 years I can tell you that you are heading in the wrong direction.

That part is available somewhere.

The Tap you are getting is not going to be lead screw grade (IE good enough) if it fits the screw at all. The screw is worn hourglass shape meaning the area that was used most IE probably the Center area is smaller than the outer areas. What you will run into is if the screw does go into the nut you are making it will be tight on the ends and loose in the middle. It will probably bind as well.

You probably be better off making a new screw as well that way you'd know if the nut was right before you put it together. Acme screw material is available from Mc Master Carr.

The other problem is if you don't get the elevation of the nut under the cross slide right the screw will bind. IE the centerline of the nut must be in line with the centerline of the screw. None of this stuff is keyed or doweled in place and if it is it will have to be changed. But as soon as you take it apart you will have realign everything.

You will be so far ahead if you just search out the correct part and install it. It will still have to be aligned but at least you will know that the part is right instead of wondering if your homemade part is.

I have been rebuilding machines for many years. I would not attempt to make this part unless there was literally no other way. I bet I'm a better machinist than you (no offense, just stating reality) and have better machines to make that part on as well. If you had an actual drawing for the part instead of "making one just like the other one," It would be a little more doable.

There are lots of guys here who are good machinists see what they think. There is a lot more to this than meets the eye.

I'd start calling Jet Dealers until I found someone who had the part or I'd adapt something close to it from another machine. I'd just bet that Jet used that same nut on something else.

http://www.ereplacementparts.com/jet-lathe-parts-c-32652_32854.html?gclid=CI3YoPvRrMoCFQ9afgody3wMOg

Randy

[ProfGAB101]

if the screw itself is bent it really isn't a big deal , you can buy acme threaded rod from enco very cheaply and replace it without a lot of bother .
and of course if the unthreaded piece is bent , just cobble the machine back together and make a new one .

you can make parts on a lathe without a working lead screw on any axis , it just takes time and a bit of effort . if you can make the chuck spin and hold the work you can fix it .

it is very important for lead screws on all axis to be as straight as possible . bent lead screws can drive you crazy with surface finish .

The Enco amce screw stock is right hand, although I think you could get LH from MSC or McMaster/Carr - and for a manual machine LH is what is required for proper operation.

Some people swear by Moglice to tighten up the existing nut - others swear at it after doing it wrong.

A good LH tap can be sourced from the UK - They still have small shops that do these odd items that keeps the world turning smoothly. Thankfully the dollar is trading well to the GBP at present, but it will still cost you a fair bit, and a good pile more for shipping/customs etc.

If you choose to make a new nut, consider fitting a matching new screw at the same time. A keyed split nut with a die spring between will give you effective zero backlash, but may be subject to deflection when ID boring.

I looked into this a few year back for a friend who wanted to convert his machine to inch from metric screws. In the end with the cost of making new replacement matching dials the total was more than half the machine price and I recommended just buying a new inch patterned machine.

[Willbird]

Tapping may be interesting as well :-). There is quite a bit of metal being removed. I have made a few ACME nuts, one for a Warner Swasey turret lathe for a past employer. It may have been 3/4" or 1"...but it had 2" to 3" of thread, and a fairly complex milled shape as well. In that case the leadscrew had a keyway, and a burr on the keyway had eaten the threads out of the nut,

We used to do one for a local company when my dad had his shop, it was a BIG one, 2" or so....and his lathe would do the 1-1/2 TPI needed, they would drill the oil holes first and it was a lot tougher until we figured out to fiddle around so that the thread did not hit the oil hole ;-).

You might try porting on Practical Machinist and see if anybody has a tap, and if they would be willing to tap the hole for you.

[fg-machine]

enco used to carry both left and right hand threaded acme rod , but times change and i cant even remember the last time i bought any threaded rod .


i think i might have some advice contrary to some of my own ... go with the flow on getting the machine back together use the general idea you already have
with out spending a lot of money .. just get everything back together and working to the best of your abilities .
and i think you will find that you have a working machine again that will do surprisingly accurate work for normal turning operations . you can learn to live with back lash and a not perfect cross slide lead screw pretty quickly . it may give you some grief for facing and parting work but it will still do fine enough work to suit most hobby needs .

all this talk of right and perfection can be rather useless at times in the real world .. things can be rather less then perfect and still work quite satisfactory .

[W.R.Buchanan]

all this talk of right and perfection can be rather useless at times in the real world .. things can be rather less then perfect and still work quite satisfactory .

Good point: Unless this machine was used in a production shop it probably just needs a good cleaning. It is hard to wear out a machine tool unless it is used hard every day and not taken care of,,,, for years!

Randy

[EDG]

Most of the small parts of any machine design are cook book parts - they come from a catalog. If they don't come from a catalog they are a catalog part that has been modified. Your ability to make parts often comes from a keyboard. Before the internet, my internet was about 20 copier paper boxes full of catalogs from places like Stock Drive Products, Allied Devices, Winfred M. Berg, McMaster-Carr, Carr Lane, All Small Parts, PIC (Precision Mechanical Components).
Somewhere there is a part already on the market that the Chinese copied with a 1/2" LH acme thread and it probably comes with a matched lead screw.

In the late 1960s or early 1970s a co-worker's old 1923 Pratt & Whitney tool room lathe quit cutting in the middle of a facing cut. The old threads in the cross slide were worn to fins and they bent over. Someone got on the phone to a distributor and the distributor called around and found a new cross slide lead screw and nut for that old junker. That was in small town Texas and the spare part was probably in Chicago or someplace far to the east. Yet it got to us in a few days and the old machine was soon back in action. I was ticked because I had an identical old P&W and it had a quarter turn of backlash in the cross slide too, but they did not buy a new screw for my machine. Yeah we could have made him another screw and nut and a pretty good one too but nothing like the ground thread lead screw that came as the replacement part matched to the new nut.




Gunor having rebuilt machines in my shop for 30 years I can tell you that you are heading in the wrong direction.

That part is available somewhere.

The Tap you are getting is not going to be lead screw grade (IE good enough) if it fits the screw at all. The screw is worn hourglass shape meaning the area that was used most IE probably the Center area is smaller than the outer areas. What you will run into is if the screw does go into the nut you are making it will be tight on the ends and loose in the middle. It will probably bind as well.

You probably be better off making a new screw as well that way you'd know if the nut was right before you put it together. Acme screw material is available from Mc Master Carr.

The other problem is if you don't get the elevation of the nut under the cross slide right the screw will bind. IE the centerline of the nut must be in line with the centerline of the screw. None of this stuff is keyed or doweled in place and if it is it will have to be changed. But as soon as you take it apart you will have realign everything.

You will be so far ahead if you just search out the correct part and install it. It will still have to be aligned but at least you will know that the part is right instead of wondering if your homemade part is.

I have been rebuilding machines for many years. I would not attempt to make this part unless there was literally no other way. I bet I'm a better machinist than you (no offense, just stating reality) and have better machines to make that part on as well. If you had an actual drawing for the part instead of "making one just like the other one," It would be a little more doable.

There are lots of guys here who are good machinists see what they think. There is a lot more to this than meets the eye.

I'd start calling Jet Dealers until I found someone who had the part or I'd adapt something close to it from another machine. I'd just bet that Jet used that same nut on something else.

http://www.ereplacementparts.com/jet-lathe-parts-c-32652_32854.html?gclid=CI3YoPvRrMoCFQ9afgody3wMOg

Randy