High speed screw cutting
Hello all.
I just baught what was advertised as an “incomplete” Ainjest high speed screw cutting atachment For my Colchester Master 2500 from E,bay.
Well actualy it was for two. One for the Master and one for a Trimph.
When i got them home to inspect i found the Master to be complete.Not just complete but with every screw and bracket needed to fit to my lathe.
Result. 😀 😀
I fitted it to the lathe only to find that the lead screw on my lathe is metric, and the halfnut in the Ainjest is English. 😥 .
My question is this.
If by fitting a metric halfnut in the Ainjest, will i be able to use the attchment ? Also what is the pitch or tpi of the metric leadscrew so i can make the part up or buy a tap to make the offending part.
I asked the same question on a Colchester forum but got what i considerd to be quite an ignorant answer indicating that it wouldn’t be possible as “gears inside were imperial” Ignorant because there are no gears in the damn thing. Just the affore mentioned halfnut, and one “idle” gear that just runs on the lead screw as per the normal thread dial indicator.
If i can get it to work it’ll be a god send ( not to mention a bargain ) as i only gave £10 for the pair. Considering a new metric is unit is £1800.
If not, well it was worth a tenner just to try.
Hope some one out there can help.
Atb, Sean.
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Viewing 5 replies - 1 through 5 (of 5 total)
Not sure yet. Am gunna get a set of acme thread dial guages and find out.
I guess there’s no way to make your existing halfnut fit the Ainjest?
What’s the diameter of your lead screw?
Im 99% sure it will work once i get a half nut that fits the lead screw.
From what bit i can gather from the Colchester site is that they were made with two diferant acme thread pitches.One metric and the other imperial.
Also i’m sure that the metric and imperial pitches were a slightly diferant angles.One being 55deg’ and the other 60 or 55.5deg’.
There’s a couple of acme taps on ebay but al probly end up buying the correct indexable tip.
The thing is, i have exploded diagrams of both metric and imperial units and they are a completley differant designes.
Ive got to try tho just to satisfy my curiosity.
This is the lead screw
And this is the halfnut.
I need to identifie the lead screw pitch then i can make the new matching halfnut up.
Atb, Sean.
I’m not that (at all) familair with this, BUT this website says
http://www.dgrdesigns.co.uk/metradial.html
So maybe it will work without any changes?
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i have a couple nuts just hanging around … haha . what size is the od of the thread , they may be the same , they look close .