Author Topic: Cowells lathe - parting off  (Read 547 times)

Offline iRon

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Cowells lathe - parting off
« on: September 29, 2020, 12:02:05 PM »
I am trying to persuade myself that I do not need (want!) a Cowells lathe.

I have heard (or read) somewhere that parting-off can be a little difficult.

Please could someone with experience give me his or her opinion and what is the best parting tool for a Cowells lathe.

Thanks, Ron.

Online Jo

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Re: Cowells lathe - parting off
« Reply #1 on: September 29, 2020, 12:04:57 PM »
I have never had any problems parting off on my Cowells  :headscratch:

I normally use HSS parting off tools on my Little C

Jo
Enjoyment is more important than achievement.

Offline iRon

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Re: Cowells lathe - parting off
« Reply #2 on: September 29, 2020, 12:20:50 PM »
Thanks for the reply, Jo.

Steel is no problem?

Do you use a 'classic' ground hss tool or an eclipse-style blade?

Ron

Offline Jasonb

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Re: Cowells lathe - parting off
« Reply #3 on: September 29, 2020, 12:21:45 PM »
Should not be a problem if you treat the machine with respect, it's never going to be good at parting off big lumps of material but within reason should be able to cope with smaller size stock which is what the machine is really meant for. A narrow parting tool will help 1mm to 1.5mm wide would be as much as I would want to use on a similar size Emco Unimat, a 3mm insert would just be too much for a small machine like this.

Offline iRon

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Re: Cowells lathe - parting off
« Reply #4 on: September 29, 2020, 12:37:11 PM »
Thank you, Jason.

Offline steve-de24

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Re: Cowells lathe - parting off
« Reply #5 on: September 29, 2020, 12:39:23 PM »
+1 for Jason's recommendation for a narrow parting off tool.

Has anyone got the rear tool post for the Cowells and is there a noticeable difference between parting off from the front or rear?

Steve

Offline JimG

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Re: Cowells lathe - parting off
« Reply #6 on: September 29, 2020, 12:48:34 PM »
I have the rear tool post fitted to my 90ME and it works very well.  I was just about to recommend to the OP that he obtain one when your message popped up.  :)  And the cross-slide is long enough to accommodate the rear toolpost being pretty well permanently fitted. 

I had a rear toolpost on my ML10 with its original short cross-slide and that toolpost was on and off regularly to give enough room in front of the chuck - getting the longer cross-slide conversion helped matters no end.  :)

Jim.

Offline Chipswitheverything

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Re: Cowells lathe - parting off
« Reply #7 on: September 29, 2020, 12:58:05 PM »
I would agree with Jason on this, I have had no trouble parting off things like studs and small diameters, using a narrow tool, and sharp!, but the low power and smallish spindle dia. are not conducive to wading into bigger sizes - brass might be OK, but steel not so much.  Depends too on the means of chucking, a small lever scroll chuck is not up to big cuts, a four jaw might do better but the work is some way cantilevered from the spindle nose. I made up a handle that can be quickly locked into the back of the spindle bore, ( if stock is not too far into the hole in the spindle ) , and if I'm in doubt about an operation like parting off, I'll pop that in and save a "bang -up".  I made up a little back tool post for the parting tool, as in photo, and would have been using the handle on the metric screwcutting job on the arbor in the other picture.  If you root about this forum there is quite a lot about the Cowell lathe, one of the USA members bought one a few years ago and sparked a fair amount of discussion.  Dave

Offline iRon

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Re: Cowells lathe - parting off
« Reply #8 on: September 29, 2020, 02:52:15 PM »
 Rear tool post and thin parting tool seems to be the prescription.

Thank you, everyone.

Offline steve-de24

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Re: Cowells lathe - parting off
« Reply #9 on: September 29, 2020, 03:43:15 PM »
A rear tool post for my Cowells is on my 'to do' list. Getting one from Cowells means parting with over 50 and you'll have to make up your own mind as to whether you think its worth it....

If you want to make one yourself then take a look at 

https://madmodder.net/index.php?topic=8110.0

Steve







Offline Bobsmodels

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Re: Cowells lathe - parting off
« Reply #10 on: September 30, 2020, 07:45:51 PM »
Here is rear post I made. 

http://www.modelenginemaker.com/index.php/topic,8167.msg174752.html#msg174752

Also made special 4 position tool holder, and boring bar holder.

Bob

Offline iRon

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Re: Cowells lathe - parting off
« Reply #11 on: September 30, 2020, 08:57:08 PM »
Thank you, Bob.