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View Full Version : Small twist on a 5C depth stop...



Doc Nickel
05-24-2008, 05:18 PM
I've been using both my lathes rather extensively lately, almost exclusively in 5C collet mode. First I discovered I needed a second collet depth stop (I had just the one I'd made a few years ago) and then I discovered I had some long, thin pieces (5/16" rod) that were slightly undersized stock. Due to the undersize, the collet gripped poorly- it held the part well enough, but it could rotate, tilting in the collet jaws like a seesaw.

So, I killed two metaphorical birds with one stone:

http://www.docsmachine.com/machineshop/5Cstop5.jpg

The new stop has a sort of circular V-block on the end, which tends to center the stock thusly:

http://www.docsmachine.com/machineshop/5Cstop6.jpg

The opposite end has a point, which can be used to center stock that has a centerdrilled hole, or short lengths of tubing.

Works great, so far. It's a bit rough in finish, but hey, it's just a tool. :D

Doc.

DICKEYBIRD
05-24-2008, 05:45 PM
Great idea Doc! That should do the trick.

I noticed that the adjustable depth stop rod on the old Sioux valve grinder has the same setup. The original chuck rollers were pretty short so a valve would probably rock a little without it.

John Stevenson
05-24-2008, 07:20 PM
Use one of these.

http://www.stevenson-engineers.co.uk/files/5CER2.jpg

5C body and holds an ER32 collet.
No gaps and they will hold undersize parallel without bellmouthing.

.

oldtiffie
05-24-2008, 09:18 PM
The ER-32 collets in a 5C adaptor is a feature of the "Spindexer" I bought from Arc Eurotrade (UK) that, as I recall, John Stevenson designed. I have not seen this feature anywhere else on any other "Spindexer". I can and do use my 5C and ER_32 collets in the same Spindexer. A top job!!!

5C collets are very fussy as regards size of the work they are holding, where-as ER collets have a 1mm "gripping range". My ER-32 collets will grip anywhere in the range of say 12 -13mm (which includes 1/2"). I use my 5C collets from my grinder in the 5C adaptor in my Spindexer as in John Stevenson's pic.

Any relatively thin/long part hanging out of the rear of a lathe collet or chuck at relatively high speed/revs is liable to "spin-off" and hit the hole through the lathe spindle. It should be retained/constrained by a "spider" (which is a method retaining the work).

It can be by way on a fitting such as in the original post. It can also be by way of a soft (wood, plastic, nylon etc) cylinder that is just a relatively neat sliding fit into the lathe spindle. It is drilled to be a relatively close fit on the job and can be hack-sawed about 3/4 of the way through along its length. It will retain the work quite well and can be easily made/replaced and inserted into and removed from the lathe spindle as required.

Any part protruding out of or beyond the rear of the lathe spindle bore is a very real potential hazard. If it is relatively long and thin and at relatively high speed/revs it may just suddenly "throw-off" at 90 degree and whip around at lathe revs. Most people remember it and guard against it even if it only happens once!!

Doc Nickel
05-24-2008, 11:47 PM
Use one of these.

-Those would be fine for individual items, but I'm making 20 to 30 parts at a time. If I have to get out wrenches to insert or remove the workpiece, I might as well just use a normal chuck.

With the 5C lever closer, I can stop the spindle, remove the part, insert the next one, and restart the spindle in about three seconds.

Doc.

toastydeath
05-25-2008, 12:09 AM
-Those would be fine for individual items, but I'm making 20 to 30 parts at a time. If I have to get out wrenches to insert or remove the workpiece, I might as well just use a normal chuck.

With the 5C lever closer, I can stop the spindle, remove the part, insert the next one, and restart the spindle in about three seconds.

Doc.

You stop the spindle before changing parts? =))))

One of the good things about leaving the spindle running is that the parts tend to center up almost instantly. Now I turn the spindle on before putting even the first part in the machine, it's just too easy to get things running true.

JRouche
05-25-2008, 12:36 AM
Great tool!!!!!

Oh, and I dont stop the spindle with the lever collet closer either, thought thats how they were meant to operate.. I dont know.. JR