Boxford screw cutting

[Tractor manParticipant @tractorman]

Hi all. I want to do some screw cutting on my boxford lathe. It only came with three basic gears to allow different feed rates on the traverse. Two 48 teeth and one 96 teeth.
The chart on the lathe shows I am missing ten gears in total to cut all possible pitches. Does anyone know where I can source a set of gears for this lathe? Or do I just try to get the ones allowing popular thread forms? Regards mick

[Tractor manParticipant @tractorman]

Need change gears

[David Standing 1Participant @davidstanding1]

As that's a 'new' Boxford, Boxford have them in stock.

 

http://www.boxford-software.com/spares/x10Menu.html

 

Be prepared for a hit to your wallet though…………..

 

 

Edited By David Standing 1 on 24/01/2017 13:21:43

[John Stevenson 1Participant @johnstevenson1]

Went and looked at that link and for a brand new lathe they didn't seem over expensive by the each.

I know it would soon mount up for a set but there won't be many about second hand at this point in time although being MOD based and more than likely from the far East there might be alternatives. However they do have splines, and not a keyway.

As an exercise I too the 60 tooth and they want £32.72 for it.

Assuming 1.5 MOD then HPC who they repeatedly tell us are "Never knowingly undersold " even though their budget rack is more expensive that their standard rack.

Require £28.41 for the same gear but then you have to machine an internal spline.

[Tractor manParticipant @tractorman]

David thanks for the link and the caution lol.
John I thank you for your input, I have emailed boxford spares to find if I can purchase change gears and await an answer. As you said it’s not out of the way for a new machine but I may buy the most useful ones to begin with. Mick

[David Standing 1Participant @davidstanding1]

Posted by John Stevenson on 24/01/2017 13:52:01:

Went and looked at that link and for a brand new lathe they didn't seem over expensive by the each.

I know it would soon mount up for a set but there won't be many about second hand at this point in time although being MOD based and more than likely from the far East there might be alternatives. However they do have splines, and not a keyway.

As an exercise I too the 60 tooth and they want £32.72 for it.

Assuming 1.5 MOD then HPC who they repeatedly tell us are "Never knowingly undersold " even though their budget rack is more expensive that their standard rack.

Require £28.41 for the same gear but then you have to machine an internal spline.

John

I agree, I don't think they are too expensive on an individual basis either, but if you bought eight or ten gears, and paid vat, and carriage, you could soon have a bill north of £3-400.

[David Standing 1Participant @davidstanding1]

Posted by Tractor man on 24/01/2017 14:28:19:
David thanks for the link and the caution lol.
John I thank you for your input, I have emailed boxford spares to find if I can purchase change gears and await an answer. As you said it's not out of the way for a new machine but I may buy the most useful ones to begin with. Mick

Mick

You're welcome.

You will probably get Gary Butterworth reply to you from Boxford. I've bought Boxford 280 stuff from him in the past, and he's been pretty helpful to me.

[Tractor manParticipant @tractorman]

I have had a reply from boxford and spares are available to buy so I am looking at the listing. Three or four gears will allow cutting of the major metric threads so I will start with them. Trouble is there is no thread indicator dial fitted to the apron. I will have to buy and retrofit the dial indicator to start cutting threads. Anyone need to buy any body parts? Lol

[BazyleParticipant @bazyle]

You don't need the indicator to cut threads. Keep the half nuts engaged and reverse it for each pass.

[Tractor manParticipant @tractorman]

Bazyle. I knew that method could be used but wanted to make things easier. I have a retracting threading tool holder on the build list and want to use that so a threading dial seems best.
Boxford do supply spares but do not have a service desk so you have to know what you want. I’m hopeful I will be able to get the necessary bits soon and report on my progress. Mick

[HopperParticipant @hopper]

Your cross slide will do a perfectly good job of retracting the tool. Helps if you have a resettable cross slide collar to set to zero. If not, a felt pen mark will do the job. Tis the way it were done for 200 years before the retracting toolholder became de rigeuer. If you run the lathe at 100rpm or less there is plenty of time to retract the tool at the end of the cut. Start out at 30rpm or so until you get a bit of practice in. Bit of practice and you'll soon be whizzing threads up at 200rpm.

[not done it yetParticipant @notdoneityet]

Gear cutting looks to be 'fairly' straightforward, so the splines seem to be the 'awkward' bit. (Thinking external and internal cutting).

So how would one go about cutting the splines (not looked at the drawings, but if of square section, I would drill most out on the PCD and progress from there somehow [small square broach per clickspring video?])?

Tractor man,

Should have stumped up the extra for a QCGB in the first place? It may have nearly paid for all these separate changewheels and made life so much easier from the outset! But I am guessing this was another of your 'bargain buys'? How much to convert to QCGB? i would never buy a changewheel machine again – unless it was " reet reel cheep"!

[Tractor manParticipant @tractorman]

Yep. A bargain buy and more than up to the job for me. It’s just a hankering I have to cut threads lol.
My raglan has a gear box so maybe I should learn to cut metric threads on an imperial machine.

[Brian OldfordParticipant @brianoldford70365]

Posted by Hopper on 25/01/2017 10:48:38:

. . . . . . . If you run the lathe at 100rpm or less there is plenty of time to retract the tool at the end of the cut. Start out at 30rpm or so until you get a bit of practice in. Bit of practice and you'll soon be whizzing threads up at 200rpm.

For the tyro I think it fair to add there is a dependency on pitch too. A course thread will whizz the saddle along the bed far faster than a fine one.

[Tractor manParticipant @tractorman]

So to be clear. I don’t need a thread dial, I do need to leave the half nuts engaged at the end of each cut, with draw the tool using cross slide reverse the lathe so the tool returns to the start of the thread , add the next in feed and run the lathe forward to the end of the cut and repeat till depth of thread achieved.
Sorry if I’m dense but I just want to be sure I can dispense with two hundred quids worth of thread dial. Mick

[John Stevenson 1Participant @johnstevenson1]

Correct.

It would help if you moved to a lift up screw cutting tool as mentioned in this thread.

**LINK**

That way it saves having to wind out, you just reverse and put the new feed on as the tool is returning.

There is a video of it here.

**LINK**

[alan-lloydParticipant @alan-lloyd]

If you can buy the thread dial do so, spend out now before its unavailable, I think I had the last thread dial from myford for my metric 254, never regretted it

[John Stevenson 1Participant @johnstevenson1]

I think I could be something a lot better with £200.

I have one on my TOS lathe and never use it. By the time you have swapped the right gear to match the thread [ 3 gears on mine ] and messed about plus you have the change of stuffing up at every engagement I find it's far quicker to power back with the half nuts still engaged and this is doing metric threads on a metric lathe.

[not done it yetParticipant @notdoneityet]

lift up screw cutting tool

Now that is a cunning ploy! Not much good for internal threads, mind!

It's easy with a dial indicator doing metric on the Raglan with not much undercut. Just need to re-engage the half nuts before reversing all the way back, but that lift up jobbie makes it so much easier, as two less operations per cut cycle.

[Tractor manParticipant @tractorman]

Hi all. Thanks to the blunt but accurate advice of not done it yet I have abandoned the idea of upgrading this lathe for screw cutting. Instead I have bought a new boxford lathe with all the bells and whistles.

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