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By DTR
#1033399
I've been doing more metalwork jobs than woodwork as of late, so I thought I'd post some stuff up.

My Hobbies wood lathe has a blind morse taper socket in the spindle, so I can't just bump out the centres from the opposite end. Apparently this is quite common on older lathes. Until now I've been twisting the centres out, but I've never been happy with this. Then when Doris bought her Coronet, I realised this has a centre ejector. It screws onto the spindle nose, and simply pulls out the centre when unscrewed. I thought this was a brilliant idea, so I endeavoured to make one....

I started by making a mandrel threaded the same as the Hobbies spindle nose. This will serve as a gauge for the ejector's internal thread, and also as a way of holding the ejector for machining:

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Then I hacksawed off a lump of bar for the ejector. I chucked it, faced off one end, then flipped it over and faced off the opposite end. Then I drilled a 1/2" hole straight through (sorry, no photos).

Next I bored the hole out to the tapping size of my spindle nose (7/8 BSW). This is a blind bore, leaving a "cap" at the end of the ejector. Then I screw cut the internal thread. I cut the thread almost to full depth:

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And finished the thread with a tap:

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Now the ejector can be screwed onto the mandrel and the two are mounted back in the lathe. A skim cut is taken to clean up the outside:

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And then the ejector is knurled:

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Finally the knurling is tidied up:

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The almost-finished ejector. All that's left to do is to drill a hole for a tommy bar, just in case it gets stuck

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Last edited by DTR on 04 Jun 2016, 08:53, edited 1 time in total.
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By AndyT
#1033405
Neat, tidy and very satisfying!

I've got something similar on my wood lathe, bought from Axminster and called by them a "thread protector." But it's more fun to make your own than scout around for the right size, in stock etc.
By AES
#1033467
Nice bit of work there DTR, you should be very proud of that. =D>

Especially the knurling - nice and "crisp & deep & even"! (not easy to do when you start off - DAMHIKT).

Thanks for posting

AES
By timber
#1034170
DTR wrote:Now in use

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I do like the knurling, what sort of knurl did you use single or double and where can I get one from ?? I did have a single but needed a fair bit of pressure. Went with a lathe I sold
Thanks Timber
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By DTR
#1034206
Hi Timber,

The knurler is a cheap, 2-wheel clamp type. I probably got it from RDG or Chronos, but I can't remember which now:
http://www.rdgtools.co.uk/acatalog/INDU ... 09087.html

I used to use a vintage 2-wheel "side pressure" type, the sort that carries two wheels on a pivot and ploughs in sideways. I think that one actually worked better, but I was wary of using it because of the load it imposes o the lathe bearings. Maybe one day I'll transplant the wheels from the vintage one onto the new one....
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By monkeybiter
#1034221
DTR wrote:The knurler is a cheap, 2-wheel clamp type...........
I used to use a vintage 2-wheel "side pressure" type............... but I was wary of using it because of the load it imposes on the lathe bearings


I have one of each and, like you I prefer the 'squeeze' type rather than the 'push' for the same reason. I seem to remember that you can buy knurling wheels on there own, so you can alter courseness or pitch etc., or just renew worn wheels.

Just had a look at Chronos's site, amazed, the knurling tools really are quite cheap.
By timber
#1034249
monkeybiter wrote:
DTR wrote:The knurler is a cheap, 2-wheel clamp type...........
I used to use a vintage 2-wheel "side pressure" type............... but I was wary of using it because of the load it imposes on the lathe bearings


I have one of each and, like you I prefer the 'squeeze' type rather than the 'push' for the same reason. I seem to remember that you can buy knurling wheels on there own, so you can alter courseness or pitch etc., or just renew worn wheels.

Just had a look at Chronos's site, amazed, the knurling tools really are quite cheap.

Thanks DTR And Mike
I will have to order one. It does make ones work more professional.
I have a bit of kit that came with a job lot I bought that does similar decorative stuff on bowls etc. Haven't tried it yet as I am not into bowl making.
Regards
Timber
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By monkeybiter
#1034253
I strongly recommend the 'squeeze' type, better for your headstock bearing.

Tip:- after your first pass [left to right or vice versa] if you keep the knurls engaged you can then nip the pinch-bolt up a little and gently/slowly traverse back the way you came for a second deeper go.
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By DTR
#1036440
monkeybiter wrote:Tip:- after your first pass [left to right or vice versa] if you keep the knurls engaged you can then nip the pinch-bolt up a little and gently/slowly traverse back the way you came for a second deeper go.


+1 to that
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By DTR
#1036445
This week's job - making a flycutter for the BCA....

Blank arbor chucked and turned down ready for screw cutting:

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Screw cut the thread:

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Drilled and tapped a lump of rod and screwed that onto the end:

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Then I took a skim off the face and diameter to make it true with the arbor (no photos).

Next I clamped the flycutter into a vee block fixture bolted to the cross slide. This fixture holds round stock centred on the lathe centre height for cross-drilling. The vee block has been bolted down at a 45* angle to the lathe axis. A 1/4" hole is drilled and reamed for the tool bit, then the fixture is rotated 90* to drill for a clamping screw:

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And finally the flycutter in place on the BCA:

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