How to use a scissor or clamping knurl on a lathe
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- Опубліковано 1 жов 2024
- Shows the method I was taught by a metal work teacher. There was a good video on YT showing this method, but it has been taken down. So I put up this video to replace it.
Camera: Nikon Coolpix L820 - Навчання та стиль
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I've never bothered to nominally size a shaft for the knurl pitch and it's always worked out OK for me.
The knurl wheels should re-engage just like the gears in a gear box if you do it slowly. It's nothing like screw cutting re-engagement as you have a free rolling surface (x2).
If you were to use the screw down method it is likely that you may not align with the impression correctly and will get double cutting. Rob
That style knurler seems to work well, will keep an eye out for one 👀 Thanks for the video Rob
Great video , I love UA-cam,it’s like having a thousand personal teachers.
The proof is in the end result.
Great video 👍👍. One thing that I though would have been cool is if you only went half way on the 2nd knurl to show us the difference of the 1st and 2nd knurl. But still, awesome video.
Not a criticism as the job is right, but it can be done quicker. Slow chuck speed, high feed. Keep feed engaged and throw chuck into reverse to return to start. Picking up the pitch of the knurl isn’t too important as the form is rolled onto the job more than cut hence why the diameter increases. It can help to have the tool slightly angled to the job so the pressure is heavier on one side. I generally do them dry but use a splash of coolant to keep the knurls cool. When the knurls get worn, they can chew up the job as they produce specks of swarf that can get stuck between the teeth so I run the last pass with an airline on it. I’m currently doing 55mm dia knurls by 25mm long on mild steel and they take about a minute each with 4 passes all at full depth. I’m an employed turner of 35 years but still watch videos as there’s always someone doing something different and sometimes better.
Great stuff, no over explanation, just simple instructions.
What kind of large do you have, it's super quiet, I like that.
BasementShopGuy It's a cheap Chinese CQ9325 10 x 18 ". I hate noisy lathes also. This one is pretty quiet provided the change gears are correctly adjusted. Bolton Tools/hardware sell them in the USA. Cheers Rob
Have done this since high school, I'm 52 now just got a mini lathe. Thanks for sharing this.
Enjoy your mini lathe. Cheers Rob
Nice job. Thanks for sharing.
Rob, looks great and thank you I find your videos very practical and to the point. I am new at machining and could you tell me what TPI you run the lead screw. I have a small metric 7x12 mini lathe, what do you recommend?
thanks Dave
+David James
Hi David,
I use 0.12 mm for general turning. This works well with TCMT carbide inserts and also HSS.
I can switch to 0.06 but this can be too fine for some metals and actually give a poorer finish. It does however work great with shear tools.
For fast ripping down to size I use 0.23.
So as a good all rounder I would recommend 0.12 mm.
Cheers Rob
Thanks for the video! Well done! Good information!
Thanks Rob. Do you make any effort to size the shaft diameter for "optimal" knurling, or is all that just unnecessary? I was also very impressed it re-engaged so well. I had always heard if you re-engage it is likely to cross up the knurl, but yours looked fantastic.
+Joel L: There seems to be a lot of "mumbo jumbo" going around with huge number crunching charts to get the correct dia, I have NEVER used any charts, with a scissor tool like this it just self aligns on the previous track and comes out right every time, also with a scissor type tool there is no sideways thrust on the job, and no need to be on centre height.
Quite correct any knurling tool will follow the impression left previously and follow it to some extent.
I only use the cheap fixed must be 26 year old now used every other day, no need to setup just plough straight in job done.
nice video, clear explanation: excellent
Thanks for the vid! I've always wondered how it was done!
Well that came out well, I have been watching a UA-cam tutorial where they insist that the diameter of the area is turned to the correct size ? I have never done this and always get a good diamond knurl as you have, but I do use the scissor type tool as you do, so maybe it is not required on these tools, it always just tracks in the impressions left on the first rev, the scissor type also does not put any side thrust on the job being knurled.
+Englishman French
I never use those sizing charts. I've never had a problem.
The correct longitudinal feed rate is much more important IMHO.
Cheers Rob
great vid
this is how i knurl on the lathe... i understand now that i have to meajure the OD and do some maths... but it worked like this for me to....
how to knurl on the lathe all types of knurling
🙂👍☕
Is that tracking properly?
Yes.
G'day, I enjoy your vids a lot. What's your story are you a retired fitter and turner?
I recently bought my second lathe (1st one, Chinese 9x20 has to go) an Aussie made "New Gregco" 8x17, made in the '40's. A much nicer bench lathe than the Chinese one, the compound dovetails on the Aussie one are wider than the cross-slide dovetails on the Chinese one. The only downside is it doesn't have the RPM of the Chinese one.
No, I'm just a guy from a blue collar worker family back ground.
We always had to make money go a long way, so that's been ingrained into me, and my make do videos.
I had to learn metal work like everyone else, but having done diverse jobs in my life , you pick up a few skills along the way which is good to pass on.
Overall, you can't take life too seriously.
Cheers Rob
Might I suggest a tip that I use to get 100 percent success. In your video, on your first attempt, you got a double hit on one of the knurl wheels. This happens because you have eased the tool into the moving stock while the machine was running. What you want to do is press a heavy mark into the stock on the very first revolution. Here is how I do that. Apply lube first, stop the machine, then move the knurls into position centered on the stock, now clamp the knurls firmly into the stock while the machine is not moving, go ahead and engage the feed mechanism, NOW turn on the lathe, and watch a perfect knurl happen. This method will fully mash the knurl wheels into the stock on the very first revolution. With the dents already fully established on the first revolution, when the stock rotates around the second time, it will already have a heavy dent, and this heavy dent "persuades" the knurl wheel to fall back into that dent. Try it, you will like it.
That's not how I was taught to do it. Do whatever floats your boat, but that is not the correct way.
Thank you!
Thank you. Much appreciated. As a retiree and novice engineer I’m always looking for methods I can easily remember.
Glad it was helpful! Cheers Rob
Thanks for showing this technique. I just bought the same style knurling tool. Going to try it out your way.
Rob,
Sorry I meant for knurling what do you set the TPI?
Dave
+David James
Hi Dave,
0.23 mm. The size of the lathe has no bearing on the matter, feed speed only relates to pattern pitch (coarseness).
The larger the pattern, the faster the feed speed.
For light pitches as shown (which is useful for most jobs) you would run 0.23 or thereabouts.
Cheers Rob
You got double tracking the first time but on the second pass it kind of repaired itself although I can see the double tracks in between the knurling. How did that happen?
Looks OK to me.
xynudu
If you pause at around 3:00 you can clearly see that the right slanted diagonals of the diamond knurl are finer (more closely spaced) than the left slanted diagonals which are kinda thick. Can you see it? Anyway what TPI knurls are those?
Sandarpan The first pass wasn't deep enough for the knurls to bite in evenly so it's obvious the pattern was crap - that's why I cranked it up and did a re-run. The knurls are some coarse ones I bought off of Ebay (can't remember the pitch). I find that finer knurls give more consistent results as they don't have to cut as deep/less pressure required. Also when you go deep it puts a heap of strain/flex on the knurl when you cross feed as in the video. Rob
Ok got it. I'm trying to learn about knurling as much as possible. Thanks.
Sandarpan Your welcome. It's all a learning curve. Rob
beautiful knurl, the scissor knurl does a great job
+Neds Head
Yes, they work well.
They don't put a lot of side thrust on the job, which is a good thing, especially when knurling long small diameter work between centres.
Cheers Rob
Clear instruction. Thanks
Very helpful, knurl came out great.
Good to hear. Cheers Rob
Nice and to the point, cannot wait to try out mine using this method.
Glad you found it useful. It's the correct way to do it. Cheers Rob
Thank you so much for making this a much easier task! I may have to go putting knurls on all kinds of things now :)
Rob do you make your own cutting fluid?
Yes. Kerosene and engine oil at 5:1.
@@Xynudu I do the same, people tend not to agree with it. Do you find it works well for you?
Works fine. It can smoke a bit if things get hot, but is excellent at preventing galling. It's an old timers's receipe that has been around for decades. Doesn't cause rust or give you dermatitis like the water based stuff, and it's cheap. Cheers Rob
@@Xynudu oh boy does it smoke. Do you use it for tapping as well? I was wondering if it would be any good.
I do, it's great for non ferrous, but not ideal for steel jobs. I ran out of the propper stuff some time ago. That's reminded me to get off my arse and buy some more ;) Cheers Rob
I made myself a clamp type knurler, works good, now i see your good method of using it. Thank you
Hi John,
This is exactly how knurling would be done in industry. They just drive the knurl onto the job. That's why most scissor knurls only have finger adjustment.
They don't screw the knurl down into the work, as some people seem to think it should be done.
Cheers rob
@@Xynudu This was my mistake, I was screwing the knurl down into the job. Your method is much better, faster, repeatable and gives a better result. So you have a new subscriber.
Can I start this in the middle of a shaft?
Sandarpan Sure. I always knurl before turning the job to final size. That way as knurling always gives a less than perfect edge, you can do a final machine pass/es to the edges of the knurl to clean it up and make a nice edge. Something to think about and plan ahead. Cheers Rob
xynudu
Actually I'll be knurling myself a weightlifting bar. Like this forum.bodybuilding.com/attachment.php?attachmentid=4974793&d=1350149133 , this forum.bodybuilding.com/attachment.php?attachmentid=4418391&d=1336063005 and this www.homegymbodybuilding.com/wp-content/uploads/2014/05/rogue-bar-knurl.jpg . The knurl starts and stops in the middle of the shaft quite a bit away from the edges and the knurling is done last.
Sandarpan The knurling doesn't have to be done last. It can be done at any time. You can reduce the shaft to within a couple of thou ", knurl the relevant areas, and then do a final cut along the shaft to get a clean edge against the knurls. Also those separated knurls in the final photo can be done as one full width knurl, and then the plain separators machined out of the knurl afterwards. It's your call, but that's how i would do it to get a nice clean finish. Cheers Rob
xynudu I suggest you try knurling a piece of scrap round bar to see how well it works. How clean the edges are. Then try my method and see which one gives the best result. Rob
Thanks. What would you recommend I do for knurling a hardened steel shaft say ~ 45 HRc?