Making a 3/4 x 16tpi lathe spindle thread protector?

[jon hill 3Participant @jonhill3]

Recently purchased a Coronet 2 wood lathe and want to make the above for when I am using a drive centre in the headstock. I had thought of adapting a spare chuck adaptor so that the morse taper tools will fit.

Or I had heard of a technique using a smaller tap of the same tpi and pitch held in a block in the tool post.

Any sugestions?

[jon hill 3Participant @jonhill3]

[old martParticipant @oldmart]

3/4" X 16 happens to be a UNF thread, maybe you could get hold of a nut and modify that.

[Ian PParticipant @ianp]

If its purely to cover the exposed threads when you are using the Morse socket then something as simple as a short length of PVC tube or even a turned wooden sleeve could just be a push fit.

Unless I've misunderstood the requirements.

Ian P

[Roderick JenkinsParticipant @roderickjenkins93242]

On my Coronet Minor lathe, also 3/4"x16, the nose protector is also used as an extractor for the drive centre since the mandrel is not hollow all the way through. The drive centre has a flange for extraction.

HTH,

Rod

Edited By Roderick Jenkins on 12/03/2021 17:54:27

[jon hill 3Participant @jonhill3]

Hi Roderick, do you have a pic of your nose protector perhaps I could make a copy?

Jon

[Roderick JenkinsParticipant @roderickjenkins93242]

Here you go:

Rod

[Dr. MC BlackParticipant @dr-mcblack73214]

I just spin a nut onto the mandrel thread. That can also be used to release the fixed centre (locking the rotation) when necessary.

[Howard LewisParticipant @howardlewis46836]

What is the thread form?

As already said, 3/4 x 16 is UNF, which is 60 degree form. If the form is Whitworth, it will be 55 degree, which may accept a UNF thread, (I know that a female UNC will not happily accept a Whitworth thread despite being the same pitch ).

If it is 3/4 x 16 Whit form, the thread is a special, with a finer pitch than either 3/4 SW (10 tpi ) or 3/4 BSF (12 tpi ) and will need to be screwcut. Although Tracy Tools offer 3/4 x 16 Taps and Dies (The Autumn / Winter catalogue lists Taps at £10 and Dies at £12 ex carriage and VAT. )

Howard

[Dr. MC BlackParticipant @dr-mcblack73214]

Posted by MC Black on 13/03/2021 00:54:56:

I just spin a nut onto the mandrel thread. That can also be used to release the fixed centre (locking the rotation) when necessary.

Apologies I should have mentioned, the nuts are 3/4 x 16 UNF.

I believe that's one of several standards for woodworking lathes

MC

[Roderick JenkinsParticipant @roderickjenkins93242]

I used a UNF tap to make a couple of wedge chucks which work ok. The register is also 0.750". Always tricky to determine thread forms on these late 20th century British machines. Industry seemed to make the move briefly to Unified threads before embracing Metric

Rod

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