Can someone advise me about knurling, please?

I've been using an Eagle Rock scissor knurling tool with a couple of
medium diamond knurls for some years now with satisfactory results.

I've never given any thought to the work-piece diameter in relation to
knurl pitch and have always managed to get fairly clean results -
mostly in brass and alloy. Not quite sure why but they always seem to
turn out ok.


20Motorbikes/DSC00395.jpg

What I'd like to do now is buy some sets of straight knurls but never
having tried these before, I feel I need some advice.

For example, I assume it's critical with straight knurls to calculate
the OD of the work piece as a multiple of the dia or pitch of the
knurl.

What I don't understand yet is how the two knurls are positioned so
that they mesh male to female so that the crest of the "male" matches
the trough of the "female"? Just thinking about it, I can't see how
you prevent crest meeting crest and ending up with double-tracking.

Any advice would be much appreciated.

Trevor

----- Original Message -----

From: GadgetBuilder

To: 7x12minilathe@...

Sent: Sunday, October 23, 2011 10:38 AM

Subject: [7x12minilathe] Re: Knurling

?

There are two schools of thought on knurling: to prevent doubling the OD of the work must be adjusted to match the knurl, and if the knurl doubles then increase pressure. "Religious" wars occur between these schools so expect fireworks shortly ;-)

I'm from the increase pressure school. I was doing a diamond knurl and one knurl doubled and the other worked properly. Since both knurls were working on the same diameter I concluded that diameter wasn't the controlling factor.

Straight knurls work about the same as diamond knurls. With a diamond knurl, each knurl must sync with itself. With straight knurls each knurl must sync with itself and also with the other knurl, not generally a problem since they're identical.

The problem in either case is getting them started properly so they sync. My approach is with the work stationary, engage about 1/4 of the knurl on the work and crank on some pressure. Rotate the work slowly and check for sync - if it isn't sync'ed add pressure while rotating until it syncs. (It's possible that it won't sync but I've only seen it happen once and this was on material that work hardened easily.) It is sometimes difficult to recover when doubling occurs - turn the area down slightly and try again.

Once synced, check that depth of knurl is correct then traverse the area to be knurled. I generally go down and back but some go down and then release the knurl. If the knurl isn't deep enough add pressure and make another pass. A fully formed knurl can be rough on the hands so consider this when deciding how much pressure to add. Also, try to knurl in one pass since the knurl is cold working the metal and this can cause failure where chunks of the work pull away and stick on the knurl. Doubling increases the probability of this type of failure.

Some material is difficult to knurl no matter what you do - I avoid knurling stainless when possible and some types of aluminum are prone to chunks coming off.

Always use lots of oil and low speed. Clean knurls thoroughly after each use.

Expect someone from the OD adjustment school to come by and refute all this shortly... :-)

John

--- In 7x12minilathe@..., "trevor_rymell" wrote:
>
> Can someone advise me about knurling, please?
>
> I've been using an Eagle Rock scissor knurling tool with a couple of medium diamond knurls for some years now with satisfactory results.
>
> I've never given any thought to the work-piece diameter in relation to knurl pitch and have always managed to get fairly clean results - mostly in brass and alloy. Not quite sure why but they always seem to turn out ok.
>
>
>
> What I'd like to do now is buy some sets of straight knurls but never having tried these before, I feel I need some advice.
>
> For example, I assume it's critical with straight knurls to calculate the OD of the work piece as a multiple of the dia or pitch of the knurl.
>
> What I don't understand yet is how the two knurls are positioned so that they mesh male to female so that the crest of the "male" matches the trough of the "female"? Just thinking about it, I can't see how you prevent crest meeting crest and ending up with double-tracking.
>
> Any advice would be much appreciated.
>
> Trevor
>

Can someone advise me about knurling, please?

I've been using an Eagle Rock scissor knurling tool with a couple of medium diamond knurls for some years now with satisfactory results.

I've never given any thought to the work-piece diameter in relation to knurl pitch and have always managed to get fairly clean results - mostly in brass and alloy. Not quite sure why but they always seem to turn out ok.



What I'd like to do now is buy some sets of straight knurls but never having tried these before, I feel I need some advice.

For example, I assume it's critical with straight knurls to calculate the OD of the work piece as a multiple of the dia or pitch of the knurl.

What I don't understand yet is how the two knurls are positioned so that they mesh male to female so that the crest of the "male" matches the trough of the "female"? Just thinking about it, I can't see how you prevent crest meeting crest and ending up with double-tracking.

Any advice would be much appreciated.

Trevor

What is best to use for me to clean all of the red grease off of my new 7x12 mini-lathe?

Also what affordable cutting oils does everyone use for various metals? I am starting with some 6061 Aluminum stock probably as my first cuts on the lathe. I also will want to do some mild steel and stainless steel at some point. I have some reading to do so I am familiar with the lathe and make sure I am doing everything properly. I just want to know what to order online or buy locally for cutting oil and also to clean the lathe.

And what is best for way oil? I want something that will keep the lathe from rusting if it sits a couple weeks here and there. I see various types in spray cans and bottle out there, not sure what to get.

Thanks!

-----Original Message-----
From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of Randal Williams
Sent: Thursday, October 20, 2011 5:46 PM
To: 7x12minilathe@...
Subject: Re: [7x12minilathe] Re: Best to use for cleaning red grease off lathe + oil for cutting fluid & way oil?

Instead of using their pressured sprayers, just put it in a squeeze wash bottle.? It will minimize any over-spray and waste.

-rw

---

From: nissan.370z
To: 7x12minilathe@...
Sent: Thursday, October 20, 2011 2:13 PM
Subject: [7x12minilathe] Re: Best to use for cleaning red grease off lathe + oil for cutting fluid & way oil?

?

Cool thanks. I wonder if I could put it in one of those Harbor Freight spray cans that you load your own mixture in and pressurize it with air? I have one but never used it.

--- In 7x12minilathe@..., Ward Miller wrote:
>
> Charles, I see you use a lot of WD-40. Just so you'll know, here is
> what it consists of:
>
> 50% Stoddard solvent (i.e., mineral spirits, similar to kerosene)
> 25% liquified petroleum gas, or carbon dioxide (as a propellant)
> 15% Mineral oil (light lubricating oil)
> 10% inert ingredients
>
> So, you could mix 3 parts of Mineral spirits (from the paint store) and
> 1 part light lubricating oil, and use it where you would use WD-40 and
> at a lot lower cost.
>

Charles, I see you use a lot of WD-40. Just so you'll know, here is
what it consists of:

50% Stoddard solvent (i.e., mineral spirits, similar to kerosene)
25% liquified petroleum gas, or carbon dioxide (as a propellant)
15% Mineral oil (light lubricating oil)
10% inert ingredients

So, you could mix 3 parts of Mineral spirits (from the paint store) and
1 part light lubricating oil, and use it where you would use WD-40 and
at a lot lower cost.

Instead of using their pressured sprayers, just put it in a squeeze wash bottle.?? It will minimize any over-spray and waste.

-rw