How to make this?

[colin hamiltonParticipant @colinhamilton16803]

I'm looking to convert and old freestanding pedestal grinder into a buffing machine. Would it be possible to make one of these shafts on my manual lathe. Is if possible to cut a tapered thread?

Thanks Colin

[colin hamiltonParticipant @colinhamilton16803]

[Gary WoodingParticipant @garywooding25363]

I wouldn't bother making one, they're readily available and not very expensive. Don't forget that right-hand ones have a left-handed thread. **LINK**

[Tony Pratt 1Participant @tonypratt1]

In the dim & distant past I did make one on a Myford super 7, I used a taper turning attachment to cut the tapered thread. I can't see how you would do it without the attachment?

Tony

[HopperParticipant @hopper]

Yes you can do it. And without a taper turning attachment. This maestro from Indonesia shows how at about the 5:20 mark.

 

His method is basically, turn the tapered section first. Then set up the lathe to screw cut the coarse "thread" that forms the spiral, with a suitably shaped form toolbit instead of a thread cutting tool. Then there is the interesting bit. As he screwcuts along the job, he uses the cross slide to manually make the toolbit follow the path of the taper. Quite a trick.

Note, he uses an inverted tool bit and runs the lathe in reverse so he cuts away from the chuck. You would have to make sure which direction you wanted your spiral to run and adjust lathe set up accordingly . I think those grinder mop mounts are "handed" so the mop always tries to screw on in use.

 

There is more of this guys' antics on the thread on here called "A Great Machinist". I have learned a lot of great little tricks from him and a bunch of others like him in Indo, Vietnam and Pakistan. Necessity is the mother of invention over there where you can't just buy a solution to every problem.

Edited By Hopper on 22/02/2022 10:51:10

[Tony Pratt 1Participant @tonypratt1]

Yes worth a go, I would imagine scrap rate would be high.

Tony

[Martin KyteParticipant @martinkyte99762]

Clockmakers have been cutting fusees for many years by removing the leadscrew from the cross slide, enguaging the screw cutting feed and applying pressure to the cross slide by hand in order to produce the groove for the clock line. I've done a few and have never produced a scrapper.

regards Martin

[BazParticipant @baz89810]

Made one a couple of weeks ago for my daughter, she has an Axminster polishing machine that takes 6 inch mops but they are held like grinding wheels with flanges and a nut. She wanted to be able to use smaller mops and so we decided she needed a pigtail. Axminster sell them but they are clamped on by grubscrews, I don’t like the idea if the shaft getting graunched up by the screws or one becoming loose and hitting her in the face so my version screws on the end of the spindle. I used taper turn attachment set at about 10 degrees and 12 tpi, the coarsest thread the lathe will cut. I used a screw cutting style tool but at about 40 degree angle, and for depth, cut it until it looks right. Took about an afternoon to do.

[HopperParticipant @hopper]

Posted by Tony Pratt 1 on 22/02/2022 11:04:26:

Yes worth a go, I would imagine scrap rate would be high.

Tony

Yes, I imagine a few "practice" pieces would be in order.

I would say the trick is to start at the large end and screwcut toward the small end, as he does in the video. That way if you hesitate, the tool simply goes off into empty space and you can go back and start again, no worries. But trying to do it the other way, starting at the small end, would mean any hesitation on the cross slide would result in a major dig in of biblical proportions!

[colin hamiltonParticipant @colinhamilton16803]

This forum is awsome.

I was going to buy but my pedestal spindles are chunky so not sure if I could buy. Also I've spent shed loads on the machines so it seems odd not to spend more on materials than buying and having a go!!!

Sounds like manual control of depth on the course setting making use of a home ground tool is the way to go. What could possibly go wrong!!!

Cutting from thick to thin makes a lot of sense

[Dave WoottonParticipant @davewootton]

I can remember at the firm I trained at there was a polishing and plating shop, the tapered ends for the polishing machines were re threaded regularly when they wore. I never tried it ,the job was left to one of the old hands, a superb craftsman, he rethreaded them by manipulating the cross slide with the leadscrew engaged, I'm sure that he did as Hopper suggests started at the large end.

The polishing machines were very scary , with something like 3hp motors,I used to sneak in and use them to polish bits of motorcycle until I managed to fire a primary chaincase across the shop as it was caught by the wheel. another telling off and banishment from the polishing shop!

Dave

[HopperParticipant @hopper]

Haha. Dave I had to laugh. My Dad worked at the Chrysler factory so my first motorbike, an old WW2 Harley, ended up very well chromed thanks to the bumper plating shop. Later as an apprentice at the same place, I used to see those guys polishing bumpers and those were some scary antics. WHS would have a fit today. Let alone the open plating baths with acid and heavy metals discreetly run down the city drain on night shift.

[Dave WoottonParticipant @davewootton]

Looking back I do wonder how we survived, letting 16 year old idiots loose on powerful barely guarded machinery, I don't remember many people wearing safety glasses unless grinding, and then not many. The plating shop resembled something out of a Hammer horror film, foul smelling vats of who knows what bubbling menacingly. As for the heat treatment shop I was told " careful with this it's cyanide, the antidote is up there but it's worse than the cyanide!" Basil the chap in charge used to sit near the tratment ovens to eat his sandwiches in the winter months. All this at a firm that boasted of being state of the art and at the forefront of Harold Wilsons white heat of technology.

Very handy for motorcycle mad teenagers though, I had a very shiny Triton, not sure how I survived that either.

Happy Days

Dave

Edited By Dave Wootton on 22/02/2022 13:46:10

Edited By Dave Wootton on 22/02/2022 13:48:15

[Anonymous]

The OP really needs one of these……

….set up to screwcut RH 19tpi BSPT threads:

the resultant 3/8" BSPT blowdown plugs, and a couple of embryo fusible plugs:

Andrew

[MikeKParticipant @mikek40713]

Haven't done this, but if I had to do it I think I would try it by setting over the tailstock to cut the taper *and* the thread. Does that not work?

[old martParticipant @oldmart]

Offsetting the tailstock might not be able to produce a steep enough taper, these adaptors are cheap as chips on ebay.

[Pete RimmerParticipant @peterimmer30576]

I don't use a tail for my buffing wheel. I just have a straight shank arbor that passes through the hole in the mop with a large washer either side. It runs nicely and doesn't vibrate as much as when I used the tail.

If you're only planning to use one mop most of the time it's an easy option.

[larry phelan 1Participant @larryphelan1]

Dave, your post brought back "Happy Memories" of being put to operating a pressbrake, with a "guard" which did not work at the tender age of 16.. This thing would suck you in and blow you out in bubbles, I wonder what the H&S shower would make of it these days !

We also had degreesing baths using something called Tricoetheleane [excuse the spelling, 50 years on ], this stuff would send you on a trip, no bother !

And yet, we are still around ! Who needs guards, ear defenders. facemasks ect ? These things are for wimps !

So what if you end up with being half deaf, half blind, with rotten lungs and minus a few fingers ?

Do you think the "Company" cared ? Did they hell !

Been there ,done that ect,ect.

Looking back, I ask, how did they ever get away with it ?

These days, it,s gone the other way, you can,t switch on a machine unless you have a "Cert"

Excuse me while I go and pour a strong drink, I need one !

[noel shelleyParticipant @noelshelley55608]

Drill and tapped one for a friend recently. I would not bother to try and make one, even though I have a taper turning attachment. At about £10 from the polishing shop I seem to think. It is vital that it is true to the axis of the machine it is being used on ! If you have a screw on chuck be careful running a lathe in reverse. Noel.

[mechman48Participant @mechman48]

see ..

https://w**LINK**

Cheap enough for a set to convert your grinder.

George.

[Sam Longley 1Participant @samlongley1]

I know that this sounds like a bodge but would it be possible to do the following.

Turn a taper.

Wind a copper wire around the taper, using a very thin wire between to keep equal spacing.once a pitch has been established

Solder the wire in place

Using a tool like a wood turners scraper with a "V" point ground in it just run it along the resulting grooves to form Vs

Or perhaps do the same with a triangular file

The thread does not have to be particularly accurate to carry the pad & just needs some form of LH screw.

Would that work. Or is it a rubbish idea?

Edited By Sam Longley 1 on 22/02/2022 18:36:17

[Patrick VallatParticipant @patrickvallat98682]

Health and safety….

I'm 18month away from retirement and am always surprised to see all the playmobils at work with yellow or orange clothes, blue plastic head gear and plastic goggles, even for working inside on tiny machinery, I still climb like a monkey ,wear black overall and no ear protection,I still have all my limbs and it's only me who takes care of my own security, nobody else….today's working people suffer more from stress and boredom than crushed fingers….BRAVE NEW WORLD

Just to add, I spent my first ten years of life fifty yards away from the Schaublin lahte factory at a time when it was still a large concern, all my friends have a 102, I had many but have two Myfords ML7 , a 69 Commando, 49 Triumph Thunderbird combination , a Reliant Kitteb and a Marcosc coupé, modell engineering is almost unknown here, a country of watch makers, was at the 2020 medel engineer show in London and was hooked by the amout of enthusiast present, always a pleasure to read the forum….

[VicParticipant @vic]

For Five quid I wouldn’t bother.

**LINK**

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