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Davek0974
03-09-2019, 05:34 AM
Hi all,

I have a possible repeat batch-job coming up but need to knurl around 75mm of an 8mm shaft.

I had a try this morning as not really done any before, i have a clamp type tool and tried the fitted wheels first, these were the medium of the three provide but although it did cut, one of the wheels was bored off-centre and the little lathe was not happy, it started off bad but cut in the end, this is the right-hand of the two in the picture.

http://davekearley.co.uk/wp-content/uploads/2019/03/knurl.jpg

Then i changed to the coarse wheels and they ran better but now i get a double-cut on one angle?? (left image)

Is there a secret to knurling i need to learn? Does feed-rate matter, can i expect to knurl 3" / 75mm in one hit with no tail support?

Any tips ?

Thanks

MattiJ
03-09-2019, 05:55 AM
Some pointers: https://www.youtube.com/watch?v=9Zwi0ZAUCUc

Cheap knurling tools can be tricky to beat to submission. Paul had a match with one recently:
http://bbs.homeshopmachinist.net/threads/77506-Brass-sleeve-bearing-for-knurling-wheel?highlight=knurling

Lew Hartswick
03-09-2019, 09:21 AM
I don't think you'll ever do 3" of that thin a stock without tailstock support. We do lots of knurling a school and I have no trouble getting the kids to knurl 4 1/2 inches of aluminum bar on the first try. Ive done steel pipe up to 1 1/4 (what will fit in the spindle) down to 1/4" rod (admittedly very short lengths) with the same knurling tool (one of the scissor type BUT with a new set of knurls, the tapered edge ones) . Another good thing is to knurl towards the tailstock to avoid any sliping in the chuck. It does take a bit of axial force. Slow RPM and fairly fast travel. keep it wet with any oil. Been at this for 20 years.
...lew...

Mcgyver
03-09-2019, 09:28 AM
a coarse knurl on small diameter work with a less than an ideal tool makes it a challenge.....but you did get good results for part of it. With a clamp style, I'd do it in one pass, with maybe a 5-10 thou feed rate. The clamp style with two wheels holds the work in the up and down direction, but without the tailstock, movement in the "in and out" direction may be an issue. There is a clamp style with three wheels so its entirely self supporting so you can do long very small dia work with no tailstock.

A cut knurling tool would make quick work of that....although when I've done so it wasn't with so coarse a knurl. One pass, at speed.

https://i.imgur.com/dlxDNWa.jpg

Davek0974
03-09-2019, 11:46 AM
Thanks all, seems i have some learning to do:)

I always thought knurling was forming, never heard of cut knurling, have now.

A three-wheel clamp style sounds ideal hear but i cant find one, not yet anyway.

I can modify the part for tailstock support and cut that off later.

BCRider
03-09-2019, 12:18 PM
Most of the tools are forming tools. Cut knurls are a special case. Not uncommon at all but you buy one or the other.

There's a lot of cheap and badly made tools around that make getting a good start a chore. It may well be that you simply need a better tool than what you have with better knurls.

There very much is a pitch to all this too. The knurls will try to pull themselves to a true cut like you show in one portion where it's a nice clean diamond. But if the diameter is just right it can "stabilize" on a double cut easily. Then the trick is to change to a different pitch knurl if you MUST cut that size.

If it's a simple push tool, as many are, then you most certainly want to use a tail stock with a piece that long and small. It's not really an option in fact with something that long and small. And you might well find that you need to move into the work through the middle then ease off as you get closer to the chuck. In effect riding along with a consistent amount of pressure through the portion where the work tries to flex away from the tool.

For long and skinny like this a clamp style tool would be aces. Far easier and more consistent as all the pressure needed is kept within the tool so the part can't flex away from the knurls easily.

But the cheap clamp style tools are not always the best either. Some of them are going to work a lot better if you take some time to improve them with things like less wobbly pins and the like. It has to hold the knurls so they sit at proper right angles to the work surfaces to get a nice formation.

Davek0974
03-09-2019, 12:26 PM
thanks, I do think this tool is junk, has slop everywhere and probably not worth trying to patch up.

I'll look for a better tool.

Mcgyver
03-09-2019, 12:36 PM
A three-wheel clamp style sounds ideal hear but i cant find one, not yet anyway.
.

I first encounted them in watch/clock stuff where you might be making very small diameter tools so it needs that self supporting function. Horia makes a beautiful one, and they are very proud of it (as they are all their stuff, but its as good as it gets). There's also Knurlmaster which are more reasonable

http://www.penntoolco.com/eagle-rock-knurlmaster-hand-knurler/

Bob La Londe
03-09-2019, 12:54 PM
Knurling seams pretty easy. Just scrub the ice really hard if your puck is moving to slow, and maybe create smooth paths to change its course. I never understood why it was an Olympic sport.

Frank Ford
03-09-2019, 01:11 PM
If the job's likely to repeat and is worth it, you might look for a turret knurling tool. I have a job I do occasionally where I knurl the full length of 1/4" drill rod. So I got a Hardinge turret tool off eBay, made a special tool holder for it, and set it up for just what I needed:

http://www.frets.com/HomeShopTech/Projects/LongKnurl/longknurl20s.jpg

I don't dismount the tool from the holder or ever adjust it at all - I just take it out for that one job and stick it back in the drawer.

It does a great job:

http://www.frets.com/HomeShopTech/Projects/LongKnurl/longknurl09.jpg

A decade after I set it up, I can take it out, run it over a drill size "B" 0-1 rod and end up with a 0.249" (+ - .001") knurled rod anytime I need it.


Here's the full deal: http://www.frets.com/HomeShopTech/Projects/LongKnurl/longknurl.html (http://www.frets.com/HomeShopTech/Projects/LongKnurl/longknurl.html)

PStechPaul
03-09-2019, 03:50 PM
There is a good discussion of knurling tools here:

http://bbs.homeshopmachinist.net/threads/74909-Is-this-knurling-tool-any-good?highlight=knurling+tool

The other thread shows how I re-bored and added a bushing to a knurling wheel that was eccentric:

http://bbs.homeshopmachinist.net/threads/77506-Brass-sleeve-bearing-for-knurling-wheel?highlight=knurling

I also bought a few sets of knurling wheels from Aliexpress. They also needed some work.

https://www.aliexpress.com/item/2pcs-Positive-Negative-Knurling-Tool-Diagonal-Knurl-Wheel-1mm-Pitch/32846825270.html?spm=a2g0s.9042311.0.0.27424c4d8IS IjW

https://ae01.alicdn.com/kf/HTB1Swj.KeuSBuNjy1Xcq6AYjFXaV.jpg
https://ae01.alicdn.com/kf/HTB1xjLCB5OYBuNjSsD4q6zSkFXaW.jpg

They also have sets with a tool holder. It is hinged to apply equal pressure to both wheels, but the scissor type is better

https://ae01.alicdn.com/kf/HTB13TqVXI_vK1Rjy0Foq6xIxVXaw.jpg
Here is a scissors type tool I made. It's not quite finished, but it works, and cost nothing but time and materials I had on hand:
http://enginuitysystems.com/pix/tools/Knurling_Tool_4935.jpg

Yondering
03-11-2019, 01:06 PM
These are scissor knurling tools: https://www.wttool.com/index/page/category/category_id/16561/?utm_medium=cpc&utm_source=SiteChampion

I'd consider Paul's home-built tool above a clamp tool, not a scissor tool. That clamp style is a weaker design and is harder to get enough bite to track correctly.

OP - yes there is a secret to good knurling - take a deep enough bite right at the start to do the complete knurl in one pass. With a deep bite, it'll track correctly from the start without giving the problems you experienced.

Of course, that assumes you have knurl wheels that track straight; if you don't, that's the first thing to address.

fixerdave
03-11-2019, 01:45 PM
I first encounted them in watch/clock stuff where you might be making very small diameter tools so it needs that self supporting function. Horia makes a beautiful one, and they are very proud of it (as they are all their stuff, but its as good as it gets). There's also Knurlmaster which are more reasonable

http://www.penntoolco.com/eagle-rock-knurlmaster-hand-knurler/

I've had reasonable success with a cheap(ish) scissor type but this concept looks way better. There must be a reason it isn't standard for lathe work. What are the drawbacks? Any HSM articles/plans for making one?

David...

Mcgyver
03-11-2019, 01:53 PM
Any HSM articles/plans for making one?
David...

not that I know of, but I bet it would be popular, especially given Horia's prices

Davek0974
03-11-2019, 02:04 PM
These are scissor knurling tools: https://www.wttool.com/index/page/category/category_id/16561/?utm_medium=cpc&utm_source=SiteChampion

I'd consider Paul's home-built tool above a clamp tool, not a scissor tool. That clamp style is a weaker design and is harder to get enough bite to track correctly.

OP - yes there is a secret to good knurling - take a deep enough bite right at the start to do the complete knurl in one pass. With a deep bite, it'll track correctly from the start without giving the problems you experienced.

Of course, that assumes you have knurl wheels that track straight; if you don't, that's the first thing to address.

Finding a good scissor style in the UK is not easy, I bought the one i have many years back, it was the sort that every supplier seemed to have, very popular and cheap - its a piece of crap in reality, could be made better using a chisel and club hammer :(

They still show the same one though and i dont want to get junk twice.

I did another test tonight and using info learned to date it actually did work, i just need a better tool i think.

fixerdave
03-11-2019, 02:06 PM
not that I know of, but I bet it would be popular, especially given Horia's prices

It can't be that hard... but then I started thinking about it... maybe just mounting a couple of rocker type heads in a scissor frame. But, the 2 wheel side can't rock or it would just flip out, but it has to slide back back and forth to balance the pressure. Easy on a hand tool... but a bit tricky on something mounted in a lathe. Still thinking about it... don't know why as I don't really need it and the last thing I need is another project... but I can't stop thinking about it. Dang!

David...

Edit: 2 cheap rocker knurlers on a scissor frame. Replace the bottom (or top... be easier to get at) pivot pin on the rocker with a bolt, maybe scribe a line across it and the frame indicating level(ish). Then, snug down the scissor frame, run the cross-slide until the alignment marks agree, lock the cross-slide, then tighten that rocker solid so it can't pivot. Then, clamp the scissor down hard, letting the other side rock as necessary, Might work... DANG!

old mart
03-11-2019, 02:49 PM
My efforts at knurling improved when I kept a good amount of oil flowing to wash away the particles. If you have a coolant pump on the lathe, use it.

MattiJ
03-11-2019, 03:11 PM
My efforts at knurling improved when I kept a good amount of oil flowing to wash away the particles. If you have a coolant pump on the lathe, use it.

Strong compressed air blast also helps alot. That what I use for cut knurling as my lathe is not equipped with flood coolant

Davek0974
03-11-2019, 03:40 PM
It did work better with tons of oil on it.

I need to find a better clamp type tool with decent wheels.

H380
03-11-2019, 03:54 PM
My $.02. Use lots of threading oil. I mean lots as in a constant flow/drip on the wheels as you are feeding. I also use a toothbrush and brush hard WITH OIL between passes. I don't disengage the feed. I stop the lathe, brush and flush with oil, reverse the direction, feed in, restart the lathe, drip oil on the wheels, stop lathe, repeat. The outcome depends a lot on how big and heavy your lathe is.

MattiJ
03-11-2019, 03:56 PM
Finding a good scissor style in the UK is not easy, I bought the one i have many years back, it was the sort that every supplier seemed to have, very popular and cheap - its a piece of crap in reality, could be made better using a chisel and club hammer :(

They still show the same one though and i dont want to get junk twice.

I did another test tonight and using info learned to date it actually did work, i just need a better tool i think.

Good, Cheap, Easy. Pick two ;)

Hommel-Keller wheels and shop made tool.

Davek0974
03-11-2019, 05:55 PM
I just want a decent tool for light use. I really don't make any tool that i can buy, better things to do with time etc.

Seems i'm limited to the same 20 pile of junk i have, a 300+ professional heavy duty item or DIY - we get bugger all choice from what i can see so far :)

thaiguzzi
03-12-2019, 01:11 AM
I just want a decent tool for light use. I really don't make any tool that i can buy, better things to do with time etc.

Seems i'm limited to the same 20 pile of junk i have, a 300+ professional heavy duty item or DIY - we get bugger all choice from what i can see so far :)

You are in the UK.
I've said it before, i will say it one more time.
Hemingway Kits in England sell the plans, drawings and materials to make the Marlco type clamp (scissors) knurler.
The Marlco (google it), long ceased manufacture but was reknowned as one of the best knurlers one could buy.
For less than 40 quid and a weekend of your time, you can have the Hemingway Kits knurler knurling quality, consistent knurls to your heart's content.
One happy owner.
If you've got "better things to do with your time", i can't help you.

MattiJ
03-12-2019, 02:55 AM
I just want a decent tool for light use. I really don't make any tool that i can buy, better things to do with time etc.

Seems i'm limited to the same 20 pile of junk i have, a 300+ professional heavy duty item or DIY - we get bugger all choice from what i can see so far :)

Well now you just need to decide if you "can" buy the 600+ professional tool or if you have time to make it by yourself at that price :rolleyes:

Wasn't able to find online price for the 3-wheel Zeus knurler but I'm pretty sure its more like 1200 than 600

Yondering
03-12-2019, 02:23 PM
You are in the UK.
I've said it before, i will say it one more time.
Hemingway Kits in England sell the plans, drawings and materials to make the Marlco type clamp (scissors) knurler.
The Marlco (google it), long ceased manufacture but was reknowned as one of the best knurlers one could buy.
For less than 40 quid and a weekend of your time, you can have the Hemingway Kits knurler knurling quality, consistent knurls to your heart's content.
One happy owner.
If you've got "better things to do with your time", i can't help you.

It sure seems like a lot of people confuse clamp type and scissors type (including a lot of advertising). What you described above is a clamp type. A scissors type is what I linked to earlier in the thread, and looks like a pair of scissors - the adjustment is on the opposite side of the pivot from the work, rather than the same side like a clamp knurler.

Even if the OP doesn't want to make his own though, the versions I linked to are only around $30, and it's 2019, someone in UK can order one same as I can here, it doesn't have to be sourced locally. I agree with you, it seems like he has a defeatist attitude and doesn't really want to put out the effort to solve the problem.

hareng
03-12-2019, 03:25 PM
Finding a good scissor style in the UK is not easy, I bought the one i have many years back, it was the sort that every supplier seemed to have, very popular and cheap - its a piece of crap in reality, could be made better using a chisel and club hammer :(

Why dont you ignore all this diy crap, i say that because every video or piccy someones ever done with a clamp type i would throw in the bin. What i mean to say is i have never ever seen a respectable knurl done with a clamp/scissor style.

Leaves you two choices a cut knurl or conventional self adjusting twin wheel mines a cheapy bought 27 years ago used daily where quality and name is paramount.

Davek0974
03-12-2019, 05:50 PM
It sure seems like a lot of people confuse clamp type and scissors type (including a lot of advertising). What you described above is a clamp type. A scissors type is what I linked to earlier in the thread, and looks like a pair of scissors - the adjustment is on the opposite side of the pivot from the work, rather than the same side like a clamp knurler.

Even if the OP doesn't want to make his own though, the versions I linked to are only around $30, and it's 2019, someone in UK can order one same as I can here, it doesn't have to be sourced locally. I agree with you, it seems like he has a defeatist attitude and doesn't really want to put out the effort to solve the problem.

Its not defeatist and FYI i have spent plenty of time looking for affordable usable knurl tools, I don't know any overseas suppliers, warranty/returns would be out of the question and, for your information the company you linked to does not ship outside of the USA.

I now have enough info to select or make what i need, the Hemingway stuff looks good and maybe what i choose.

Davek0974
03-12-2019, 05:54 PM
Why dont you ignore all this diy crap, i say that because every video or piccy someones ever done with a clamp type i would throw in the bin. What i mean to say is i have never ever seen a respectable knurl done with a clamp/scissor style.

Leaves you two choices a cut knurl or conventional self adjusting twin wheel mines a cheapy bought 27 years ago used daily where quality and name is paramount.

By 'self adjusting twin wheel' i gather that is the swivel-head push-feed dealy that pops up a lot?

I doubt an 8mm rod of aluminium would be able to resist the force for push-feed knurling even with tailstock support, that is why i favour the clamp style tool. I don't know what forces are involved in two-wheel cut-knurling and a three-wheel tool although ideal is just simply out of range price-wise.

Yondering
03-12-2019, 06:07 PM
What i mean to say is i have never ever seen a respectable knurl done with a clamp/scissor style.


You mean like this?
304 stainless
https://i.imgur.com/eP54EzZ.jpg

or like this?
grade 5 titanium
https://i.imgur.com/kM1pqsr.jpg

These were done with one of the scissor tools I linked to earlier.
My knurls with a scissor tool turn out like that every time, repeatably, in stainless, carbon steel, titanium, and aluminum. The technique is important and a lot of guys don't get it right, but it's fairly easy once you know what to do.

lynnl
03-12-2019, 07:51 PM
VERY nice looking knurls, Yonderling!
Did you do those with that same scissor tool shown in the link you provided earlier?

i.e. this one: https://www.wttool.com/index/page/category/category_id/16561/?utm_medium=cpc&utm_source=SiteChampion

That's a very reasonable price. In fact I would've guessed almost too reasonable. Which is why I asked if that's what you used.

Lew Hartswick
03-12-2019, 11:02 PM
My $.02. Use lots of threading oil. I mean lots as in a constant flow/drip on the wheels as you are feeding. I also use a toothbrush and brush hard WITH OIL between passes. I don't disengage the feed. I stop the lathe, brush and flush with oil, reverse the direction, feed in, restart the lathe, drip oil on the wheels, stop lathe, repeat. The outcome depends a lot on how big and heavy your lathe is.
If you're getting "chips" (stuff) in the knurl then you are breaking stuff off the work. That says you are not allowing the metal to flow as it should with conventional knurling. (as opposed to cut nurling). At the end of a knurlng pass the work should be just oily. On aluminum one pass should be sufficient, even on steel tubing/pipe I get a clean knurl in one pass with a "medium" knurl and no "residue" that needs to be brushed off, just the oil .
...lew... OK here are some links to what I'm talking about. One pass .
These are on aluminum
https://i.postimg.cc/K4vzvjJj/37.jpg (https://postimg.cc/K4vzvjJj)
https://i.postimg.cc/q6RMmDzy/38.jpg (https://postimg.cc/q6RMmDzy)
https://i.postimg.cc/gX42HbkG/39.jpg (https://postimg.cc/gX42HbkG)
https://i.postimg.cc/HVrkXKGC/91816.jpg (https://postimg.cc/HVrkXKGC)
https://i.postimg.cc/bs4NTT8S/92000.jpg (https://postimg.cc/bs4NTT8S)
https://i.postimg.cc/68R61v5j/92030.jpg (https://postimg.cc/68R61v5j)
These are on steel
https://i.postimg.cc/PLsJtMRn/6-Knurl.jpg (https://postimg.cc/PLsJtMRn)
https://i.postimg.cc/Rqs03mDR/7.jpg (https://postimg.cc/Rqs03mDR)
https://i.postimg.cc/njnLmhxd/8.jpg (https://postimg.cc/njnLmhxd)
..lew..

Davek0974
03-13-2019, 03:19 AM
Why dont you ignore all this diy crap, i say that because every video or piccy someones ever done with a clamp type i would throw in the bin. What i mean to say is i have never ever seen a respectable knurl done with a clamp/scissor style.

Even I have seen respectable knurls done with these tools so i know that statement is duff, even my POS tool made a reasonable effort on one of my tests, its just not repeatable and its all down to the poor quality of the build.

Those knurls look ideal to me.

Magicniner
03-13-2019, 04:43 AM
Over a long period of time I've tried many knurling tools, I've ended up with J&S & Integi clamp types and Quick & Integi cut types plus a couple of single wheel push types for special knurls.

I know many careful folk moan incessantly about the expense but I kept searching the auction sites and tool supplier sites regularly over several years and picked them all up for a fraction of retail, all either second hand or on clearance. Over the same period of time I also found almost the same set of tools for a friend, again at a fraction of retail.

Quick, Good, Cheap, pick two.

thaiguzzi
03-13-2019, 11:25 AM
It sure seems like a lot of people confuse clamp type and scissors type (including a lot of advertising). What you described above is a clamp type. A scissors type is what I linked to earlier in the thread, and looks like a pair of scissors - the adjustment is on the opposite side of the pivot from the work, rather than the same side like a clamp knurler.

Even if the OP doesn't want to make his own though, the versions I linked to are only around $30, and it's 2019, someone in UK can order one same as I can here, it doesn't have to be sourced locally. I agree with you, it seems like he has a defeatist attitude and doesn't really want to put out the effort to solve the problem.

Gotchya.
Thanx

thaiguzzi
03-13-2019, 11:26 AM
Why dont you ignore all this diy crap, i say that because every video or piccy someones ever done with a clamp type i would throw in the bin. What i mean to say is i have never ever seen a respectable knurl done with a clamp/scissor style.

Leaves you two choices a cut knurl or conventional self adjusting twin wheel mines a cheapy bought 27 years ago used daily where quality and name is paramount.

Comedian.

Yondering
03-13-2019, 12:01 PM
VERY nice looking knurls, Yonderling!
Did you do those with that same scissor tool shown in the link you provided earlier?

i.e. this one: https://www.wttool.com/index/page/category/category_id/16561/?utm_medium=cpc&utm_source=SiteChampion

That's a very reasonable price. In fact I would've guessed almost too reasonable. Which is why I asked if that's what you used.

Yes, that's what I used. At least, the tool I used came from that link about 7-8 years ago. Mine is the "standard" size; it's a fairly beefy part with plenty of strength, which lets you bite into the work hard so the wheels track correctly from the start. (That is partly why I'm not impressed with the smaller/weaker clamp tools.)

The only thing I changed was to to flip the tool over so the adjustment screw points up and tack weld the head of the cross bolt to one arm, just to make it easier to tighten (that head was round with no hex to grab with a wrench).

I've been meaning to replace the wheels on mine, since one of them has chipped teeth, but it still knurls reasonably well for what I'm looking for.

BCRider
03-13-2019, 12:33 PM
Dave, you figured out a solution yet?

If you want a reasonable balance between time and cost Stefan Gottswinter has a video on what he did to correct the issues he found on a cheap scissors style.

Now Stefan, in his usual way, quite overdid it and turned the job into a major re-work. But really looking at my own cheap scissors style which looks a lot like the one Yonderling posted the link for truly only needs two things.

First is a properly sized bushing that is the right length so when I tighten the pivot bolt the arms and mounting leg don't all lock up solid. Or a newly made then hardened and tempered shoulder bolt to do the same thing. It's a very thin bushing so the shoulder bolt idea would be better.

Second is that the cheap scissors style use pressed in pins to hold the knurls. So "one size fits all". I want to press them out and make up some manner of slip fit pins for the rollers. To match the sizes of the knurls without slop this likely means grinding or lapping out the arms since I'm sure they are hardened and tempered or they'd bend easily under the forces. Otherwise I'd ream them to the size of the proper pins. And I'd also counterbore for the shallow flat head I'd include on such pins so there's no protrusion when working close to the chuck jaws.

All in all not a lot of putzing around. And it'll end up being a better knurl that can be used on longer and more slender parts as you showed. But mostly they are just more kindly to the headstock bearings.

hareng
03-13-2019, 03:40 PM
Even I have seen respectable knurls done with these tools so i know that statement is duff, even my POS tool made a reasonable effort on one of my tests, its just not repeatable and its all down to the poor quality of the build.

Those knurls look ideal to me.

Well there you go some people have a far lower standard than others.

hareng
03-13-2019, 03:42 PM
Comedian.

Well ive stung you boys for money being the undisputed best.

Davek0974
03-13-2019, 04:55 PM
Well there you go some people have a far lower standard than others.

Some people talk a load of crap too.

awemawson
03-13-2019, 05:16 PM
Dave,

When I was looking into cut knurling a few years back, the late (and sorely missed) John Stevenson pointed me at an article in Model Engineer that he had been involved with with plans to make a cut knurler, and it wasn't that complex. I don't think he wrote the article, but he may have.

Mainly now on my manual lathe I use one of my Marlco style, as they are easily set up - I have a pair on Dixson holders, one coarse and one fine. But I was fortunate enough to pick up a commercial cut knurler on eBay and it is a joy to use, but I tend to use it on my CNC lathe usually.

If you are setting up for production though, as I said on another forum, you really need a Swiss style lathe so the stock advances though the collet and is supported close to where you are knurling.

Davek0974
03-13-2019, 05:33 PM
Thanks, "production" in my terms is very low qty and small batches (1-10) a few times per year, a new lathe is just out of question at present.

I'm looking at a few options at present re tooling so hopefully should be sorted soon.

Yondering
03-13-2019, 05:56 PM
Well there you go some people have a far lower standard than others.

I'd sure like to see some examples of your knurling jobs, and what you consider an acceptably high standard.

There's a lot of talk and advice from guys in this thread, but I've only seen decent knurling results by a few of them.

JRouche
03-13-2019, 05:57 PM
Wasn't able to find online price for the 3-wheel Zeus knurler but I'm pretty sure its more like 1200 than 600

You talking about this tool? Its a nice piece. And yeah, prolly very expensive. JR

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=4848&d=1552514141

Yondering
03-13-2019, 06:30 PM
That's an interesting tool. I bet a guy could make one, with some careful machining of the jaws on a small 3 jaw scroll chuck. I wonder if the wheels are timed to each other though?

Seastar
03-13-2019, 07:54 PM
They time themselves.

sarge41
03-13-2019, 09:50 PM
If you want good knurls consistently, find out what the pitch of your knurling tool is. To do that, divide the circumference of the knurling wheel by the number of teeth on the knurl. Then determine if the pitch of the tool will go into the circumference of the job (to be knurled)an even number of times. many times, that diameter of the job, can be adjusted by filing or polishing a few thousandths off. When the knurl has gone around, it is important that the knurling tooth, drop back into the original track. If you think I have been smoking some wacky weed, just remember that I have been at this work for about fifty years or so. Good luck.

Sarge41

On edit: A good knurl can be done with a cheap import, scissors tool. When you determine the pitch of your tool, mark it on the tool for the next time.

Joel
03-14-2019, 01:47 AM
Cheap Chinese scissors knurling tool results - 30" of it per part (!), and I did a LOT of them (was doing all of the mfg of my own product at the time).
One pass on 1 1/4" dia DOM tube, they had to look perfect and no flaking allowed as they got ENP plating and had to hold up to a wet and abusive environment. I did switch to quality convex knurls and carbide pins (only because of the long length and # of parts). I long ago quit worrying about the stock diameter when knurling and just tweak the pressure as required.
As was mentioned, an aggressive start is key to prevent double tracking. I have my own 'starting' method to assure perfection every time.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=4850&d=1552541125

Davek0974
03-14-2019, 03:24 AM
Looking at the detail here, my POS fails because of the serious slop in the arms that hold the wheels, it cannot be made to track correctly as bot arms twist a different amount - it really is poor.

But, it 'could' be fixed if nothing else pops up, still working on this and have plenty of time, a three-wheel unit would be great and i am on the lookout for a used unit.

awemawson
03-14-2019, 03:31 AM
Dave, for your low volume would it be perhaps sensible to explore outsourcing? Someone already tooled up would be able to knock them out cheaply.

MattiJ
03-14-2019, 04:16 AM
That's an interesting tool. I bet a guy could make one, with some careful machining of the jaws on a small 3 jaw scroll chuck.

That's exactly what I was also thinking!

MattiJ
03-14-2019, 04:18 AM
Looking at the detail here, my POS fails because of the serious slop in the arms that hold the wheels, it cannot be made to track correctly as bot arms twist a different amount - it really is poor.

But, it 'could' be fixed if nothing else pops up, still working on this and have plenty of time, a three-wheel unit would be great and i am on the lookout for a used unit.

You get really sturdy one if you place the clamping screw to opposite side of the workpiece.
And making one out of key stock or gauge plate takes probably like 30 minutes which includes already 2 iterations and 15 minutes of head scratching. (takes more time to order the material..)
Knurl wheels are the critical part but quality ones are available as spares.
And use carbide pins if you plan to do lots of knurling.

Davek0974
03-14-2019, 04:34 AM
You get really sturdy one if you place the clamping screw to opposite side of the workpiece.
And making one out of key stock or gauge plate takes probably like 30 minutes which includes already 2 iterations and 15 minutes of head scratching. (takes more time to order the material..)
Knurl wheels are the critical part but quality ones are available as spares.
And use carbide pins if you plan to do lots of knurling.

Thanks

Davek0974
03-14-2019, 04:35 AM
Dave, for your low volume would it be perhaps sensible to explore outsourcing? Someone already tooled up would be able to knock them out cheaply.

I did explore that briefly, price was not sustainable, they wanted bigger volumes than i could offer. I also tend not to outsource unless there is absolutely no way to make it in-house.

Yondering
03-14-2019, 04:03 PM
If you want good knurls consistently, find out what the pitch of your knurling tool is. To do that, divide the circumference of the knurling wheel by the number of teeth on the knurl. Then determine if the pitch of the tool will go into the circumference of the job (to be knurled)an even number of times. many times, that diameter of the job, can be adjusted by filing or polishing a few thousandths off. When the knurl has gone around, it is important that the knurling tooth, drop back into the original track. If you think I have been smoking some wacky weed, just remember that I have been at this work for about fifty years or so. Good luck.

Sarge41

On edit: A good knurl can be done with a cheap import, scissors tool. When you determine the pitch of your tool, mark it on the tool for the next time.

No. You do not have to do any of that. Just take a deep bite with the knurling tool at the start, and forget about stock diameter. It does not matter when you force the knurl to bite deeply enough.

The knurled parts I posted pictures of earlier are evidence of that, and I get the same results every time.

Davek0974
04-06-2019, 10:04 AM
Just an update for closure

Finally got back onto this job, rebuilt my POS knurling tool, reamed the joints and fitted turned pins, that got rid of 90% of the slop and it actually works now!

First batch done in no time, nice heavy cut with tailstock support...

https://www.practicalmachinist.com/vb/attachments/f38/253876d1554558907-knurling-how-knurl1.jpg