Knurling tools

I feel the need to knurl.
Busy Bee has a bunch of knurling tools on sale. I have a 9x20 lathe so I suspect only the clamping type with 3/8" shank comes into play.
Can anyone comment on the available selection? What to look for? What to ask about?
http://www.busybeetools.com/categories/Metalworking/Knurling-Tools/Knurling-Tools /
Thanks,
Michael Koblic, Campbell River, BC
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On Thu, 31 May 2012 21:26:49 -0700, snipped-for-privacy@gmail.com wrote:

i had nothing but poor results with knurling till I scored a high quality scissor type tool. These offers look wimpy to me. I'd suggest trolling eBay for a bit beefier one.
The trick to knurling is to knurl completely to depth in one pass, this takes a lot of force and has to be rigid.
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http://www.busybeetools.com/categories/Metalworking/Knurling-Tools/Knurling-Tools /
I have a cheap version of the scissors or clamping type. It took some fine tuning and tightening up to make it work well enough. When it runs over center it lifts the far side of the carriage.
Sometimes I get better results by starting with only a slight overlap at the end of the work, to allow the knurls to bite in more easily, then feeding across. The center joint has to be carefully tightened for this so the arms don't deflect and twist the knurls.
I think the work circumference has to be an integer multiple of the knurl pitch. The knurls on mine are 3/4" in diameter and have 48 teeth, equivalent to a 1" knurl with 64 teeth, or a 64DP gear. They should(?) track on any diameter that comes out even in N/64ths of an inch, and possibly the metric ones that nearly match like 8, 11, 14, 19mm.
Successfully knurled 12L14: https://picasaweb.google.com/KB1DAL/Tools#5726420861185879138 More often one knurl doesn't track. The simple fix is to leave extra length to experiment.
jsw
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On 01/06/2012 12:58, Jim Wilkins wrote:

This is a popular myth that started with the assumption that knurling is similar to gear cutting - it's not. Think about it. If you examine a knurl that hasn't synced you will find that it's consistently out of sync all round. If it was due to the circumference not being an integer multiple of the knurl pitch then you would expect the off-sync pattern to vary around the circumference - sometimes syncing properly and sometimes not. The fact that the out-of-sync pattern is maintained consistently tells you that once a pattern has been established, the wheels will follow it.
Certainly, the initial out-of-sync pass is the result of the circumference/pitch discrepancy, that's why you must start off with a good bite - the deepest you can get away with.
The secret to good knurling is to start off with a good deep impression - you mustn't pussyfoot with the initial bite. If you get a good start the wheels will synchronise with the existing pattern and you will find it impossible to change it. Once you've established the pattern, you can just increase the pressure until you get the depth you want.
It works every time with me.
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wrote:

Having done thousands of knurls over the years I only agree partly with the above statements. For a good knurl the work does indeed need to be a close approximation to the knurl pitch. But since the knurl will deform the work you eventually wind up with a knurled surface than matches the pitch of the knurl if the work is soft enough. If the piece being knurled is not able to deform fast enough before work hardening then you can end up with a crappy knurled surface. Brass will do this. It can start to flake if not knurled fast enough. The knurling process works best when the material is worked quickly. Sometimes the knurling won't come out good unless the diameter of the piece being knurled is changed a little. This happens more with diamond knurls. So if the part you are trying to knurl just doesn't look good try turning down the diameter a little. Of course all the above relates to form knurls and not cutting knurls. Eric
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I agree with Gary's comments regarding pattern size and workpiece diameter.
Excerpt from earlier reply wrt knurling: Displacement-type diamond pattern knurls should be able to work properly without concern for matching the pattern size to the diameter of the workpiece.. that's where the good bearing surfaces of the pins and proper lubrication come into play, as the knurls can creep a little to keep falling into/track the same pattern. The helical shape of diamond pattern knurls helps them track because they can slip sideways a little while they're working.. if they don't have a gap between the knurl and the holder (and good lubrication), thay can't slip which will most likely produce poor results and lots of frustration.
The method taught when I was in high school was to carefully bring the knurls into light contact with the workpiece and rock the chuck back n'forth by hand, adjusting one of the knurls until the pattern was properly spaced to produce full diamonds (not smaller parallelograms).. then bump the cross feed in a bit and rotate the workpiece over a wider arc while establishing a bite into the workpiece with the correct pattern. After applying adequate cutting lube, it was a matter of feeding into the workpiece as soon as the spindle motor was switched on. The knurls would displace the material and establish a pattern to track, so the operator could travel the workpiece and continue to feed until the desired results were attained. We didn't have scssor-style knurling tools back then.. but the same principles apply. We were students.. I'm sure experienced machinists develop/utilize different methods.
Straight knurls should also track an established pattern, although this could be a little more difficult when working with work-hardening alloys.. it may require the operator to make CNC-like movements to be able to attain consistent results for a large number of workpieces.
--
WB
.........


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On Thu, 31 May 2012 21:26:49 -0700, mkoblic wrote:

Knurling-Tools/
Little Machine Shop has scissor-type knurling tools that look considerably beefier, that come with a good selection of knurls, and they carry the knurls, to boot (Busy Bee did not list knurls for the inexpensive ones).
It's about twice the price, but it's the one that I'd buy.
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On May 31, 10:26pm, snipped-for-privacy@gmail.com wrote:

This is the sort I have: http://www.use-enco.com/CGI/INSRIT?PMAKA=505-4516&PMPXNO=952422&PARTPG=INLMK3
Mine is this exact style, except it was made in India and I bought it off the scratch-and-dent for about $20. Nice to see that they have a U.S.-made item, current price is not so nice for anyone not having a business to depreciate it. Anyway, it works well, I replaced the clamping nut with a lobed cast-iron knob from MSC. No wrench needed then. Uses standard-sized knurls, at least US-standard ones.
The Busy Bee ones remind me of the various project ones I've seen in The Model Engineer over the years for the British small hobby lathes. Might be OK for fine knurling on smaller workpieces. Prices are attractive, anyway.
Stan
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http://www.busybeetools.com/categories/Metalworking/Knurling-Tools/Knurling-Tools /
    Hmm ... if you could use the first one shown (that is -- you have the quick-change toolpost in at least AXA/Series 100 size) then you have the option of using one by Aloris which I particularly like (and which I have in the BXA size) The #19 (in my case BXA-19, in yours, likely AXA-19). You can see it on page 18 of the 2010-2011 Aloris catalog (PDF page number 20).
    The one in the photo is missing one feature which mine has. First the features in common:
1)    It fits on the dovetail of the toolpost like any other holder.
2)    It has two rigid arms which travel in dovetails, with a     leadscrew which is left-hand thread on one end and right-hand     thread on the other, and is captive in the middle, so as you     adjust it, the arms maintain centering once you have initially     set the height adjustment nut -- unless you move it to a     different lathe with different dimensions.
3)    You can change the knurls for whichever pattern you want.
4)    Once it is set for a given diameter, you can feed it onto     subsequent workpieces of the same diameter with no more     adjustment needed.
X)    The difference is that mine has a knurled knob on the top end of     the leadscrew, with four holes drilled in radially, so you can     use a "tommy bar" to tighten it if need be. It looks as though     the current one has an Allen socket at the top end.
    Also in common -- you probably don't want to pay new prices for     it. :-) The AXA size in that catalog is $302.00. Probably more     in the 2012-2013 catalog. Mine came from an eBay auction some     years ago.
    There are two currently on eBay.
        #120748127351    -- $271.95 BIN
        #250867306826    -- $265.00 BIN
Hmm ... the first one shows the knob in the top illustration, and the Allen socket in the one down in the body of the auction, so I'm not sure which you would get.
    O.K. Only the second one actually mentions the knob in the description, so I guess that the first one gives you the Allen socket.
    Anyway, if you want to purchase from the page you showed, the ones which I would suggest are:
    B267758     B3005 (maybe)     B267738     B2678 (again maybe)     B3007
    Make sure that the shank will fit your tool holders, and (if you can find that information) the knurls will separate enough to handle the largest diameter workpiece which you expect to knurl. The ones marked as "maybe" look as though they are more limited in sizes possible.
    The other styles are called "bump" knurling tools, and they put a lot of stress on the cross-slide and carriage -- and you don't have that strong a lathe to start with.
    I have used a scissors style knurling tool which has the shank going back away from the workpiece, and then the arms curving to handle a wider range of sizes without requiring getting the toolpost too far away from the workpiece. This worked well even on my little Compact-5/CNC (5" swing lathe). It was actually made by Eagle Rock (a good maker), but when I bought it from MSC, I could not tell this from the catalog listing, which simply said "Made in USA". Once I received it, however, it was marked by the maker.
    Note that once you have a good tool, you can buy other knurling rollers in various pitches and angles to swap in for your purpose. Two rollers with the same angle (other than straight) will cut a diamond pattern. Two straight ones will cut a straight knurl only (unless used in a T-style holder designed for turret lathe use, which can be adjusted to do anything with straight knurls), and one with a right-hand angle and the other with the same angle in left-hand will cut a diagonal knurl.
    Good Luck,         DoN.         
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wrote:
[...]

[...]
Thanks.
I was wondering about the B3007. I have the OEM 4-way tool post and should be able to get the 5/8" shank in there without having to worry about shimming to get it on center due to the "floating" ability of this particular tool.
Also losing $18 is not going to kill me (immediately). $270 might.
Michael Koblic, Campbell River, BC
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    Yes -- it is quite forgiving in that sense.

    Understood. The one I got was a lot more wallet-friendly. :-) That was before eBay got taken over by commercial vendors, when you could get used equipment in good condition.
    Enjoy,         DoN.
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wrote:
[...]

I will stick an order in tonight (Busy Bee also have a couple of other good deals).
I suspect that poor results will more likely be due to operator error rather than the quality of the tool :-)
I was toying with the idea of doing a simple version of knurling on my mini-mill - either just engrave each knurl with a dental burr while turning the work piece or doing it with a tap (I saw someone making gears that way). However, to get the workpiece rotating horizontally and evenly step at a time on the mill would actually be more expensive than the said $18 tool on the lathe.
Michael Koblic, Campbell River, BC
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