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Re: Hemingway Kits

Posted: Sun Mar 29, 2020 12:19 am
by Alpha1
Ovenpaa wrote:What is the all metric lathe you use?

I have a Chipmaster that although capable of metric screwcutting is only used for imperial work albeit I only work in metric!

To explain, I am of an age where I experienced the change to metric dimensions back in the 60s. At that point I chose metric and tried to stick with it yet I grew up with people who were imperial through and through so I worked with both. These days my DRO's are permanently set to metric yet I still mentally swap back to imperial for small measurements as I was brought up with British motorcycles. So when I am clocking in with a 0,01mm clock, when it is done I tend to convert the needle deflection to thousandths, so half one increment (0,005mm) is just under two tenths.

Anyways... It is not so bad, a 1/2"x20tpi (UNF) thread starts at 12,7mm and I take initial cuts at 0,1mm or four thou ish, halving it towards the end which gives a good finish as long as the machine TPM is at a decent level.

I dislike imperial drawings and always convert anything I am sent to metric and CAD so it is stored for future reference, plus CAD and metric is handy as I can very easily calculate the weight of an item by taking the material density which is always available. I am making parts for some two mile competitors and everything I do is metric even though they are using 'imperial' projectiles.

Next job when I get a chance is a DRO on the surface grinder even though the vernier scales are super accurate, I just like DROs

I need more coffee.
Its not an all metric lathe you can screwcut imperial on it I have done it. I have cut the thread for re loading dies on more than one occasion.

Re: Hemingway Kits

Posted: Sun Mar 29, 2020 11:16 pm
by Alpha1
Looking at the drawing it tells you to turn the M2 arbor down to a given dimension. You then bore a hole into a piece of round bar stock to match the dimension you have turned the 2MT arbor to and loctite the two pieces together. I thought why not just drill and tap both pieces then loctite them together . Or am I missing some thing after all the reamer does not turn its the work piece in the lathe that spins.

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 4:22 am
by bradaz11
probably because it's not needed. just cutting nd gluing is sufficient, why add an extra step if you don't have to

as for metric vs imperial. I don't mind imperial when it is in decimal form, but fractions mess me up. Like I needed a bearing the other day, I knew it was imperial, and very close to a 6001 bearing, so the ID needed to be 1/2", but what is the imperial equivilent of just over 28mm. being at work, no access to a zeus book, and googling got me no where, as any online fraction calculators deal as actual fractions, not fracttions of inch - ie 4th, 8ths, 16th etc. and half the online conversion charts I was googling only went to 1", so had to resort to looking at smalll fractions, taking the metric size, then addding that to 25.4 and seeing if it was over 28mm. 1-1/8" looks to be the kiddy

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 8:02 am
by strangesam
I bought a cheap pair of digital callipers that have the option of displaying in mm, decimal inch and fractional inch to solve that problem Bradaz11.

I just adjust the calliper to the appropriate measurement, then press the unit button to convert.

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 6:53 pm
by bradaz11
oo that could be usefull, what does it do in fractions when it is between a size?

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 7:05 pm
by strangesam
I'm honestly not sure, and cant check as they're in the tool box at work, which is closed.

From memory, I think it goes down to 1/128ths which is fine enough for my purposes, at slightly less than 0.2mm (Have posh mitutoyo ones for accurate decimal measurements)

Can't remember where I bought them, but look a lot like these ones, https://www.warco.co.uk/digital-vernier ... liper.html

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 7:08 pm
by Alpha1
Oh I like them.

Re: Hemingway Kits

Posted: Mon Mar 30, 2020 7:35 pm
by bradaz11
I think im going to have to get something simmilar then! I have too pairs of starrets, both ip rated, one is now wandering on it's zero, plus a real cheap pair that have always been pretty reliable, but can I ever find either on the bench? nooo! always the buggered set, that I keep forgetting is the buggered set.

Re: Hemingway Kits

Posted: Wed Apr 01, 2020 12:24 am
by Alpha1
They sell them on Amazon I ordered a set for £17.00.

Re: Hemingway Kits

Posted: Wed Apr 08, 2020 12:11 am
by Alpha1
Received the calipers.
The Hemingway kit is proving to be a bit of a challenge.