Knurling Tool

[19brendan81]

Hi Guys.

Does anyone know where I can get a knurling tool that will produce a good knurl? I have one at home already but it doesnt produce a very deep knurl. I want a knurl roughly akin to what you find on a socket wrench handle or something.

I will initially be knurling 32mm rollers for a grain mill but envisage the mk2 model having 50mm or even 75mm rollers so the knurl will need to handle these sorts of diameters.

Brendan

[pipeclay]

For what you are doing does it need to be a knurl or could it be some other type of pattern?

[19brendan81]

Every commercial variety uses a diamond pattern knurl, I believe its what they refer to as a coarse knurl but im not sure. Its nearly identical to the knurling on my sidchrome 1/2inch drive socket wrench. Its possible other patterns would work, but id be experimenting as ive never seen one with anything but knurled rollers.

Most of these things use 1 driven and 1 lazy roller. I believe the knurling helps to pull the grain through and as it does so it drives the lazy roller, crushing the grain in the process. Initially mine will run like this, but eventually I will cut some gears for it so that both rollers are driven.

[Metmachmad]

There are different grades of patterns available (ebay, engineering supplies, etc) fine, medium, course. Then also to get to optimum finish it does depend on technique.

[pipeclay]

Is the size the Grain gets crushed to important or is this a 1st stage opperation.

[Big Shed]

There are several types of knurling tool on the market.

I got one with my QCTP, it is the type that gets pushed in to the work. I found this very limiting and it put a lot of strain on both the cross slide and the work (I do mainly small diameter stuff, up to 20mm)

So I looked at the clamp type and it seemed to be a better way to go. I bought one on Sunday at the Bendigo Model Engineers Exhibition from LPR Toolmakers. I have done several diamond pattern knurls on both 12L14 steel and 6061 Aluminium so far and I can get a good deep knurling pattern, it is also very even. They also sell extra knurling wheels in 3 different patterns and in quite a range of pitches.

They have an Ebay shop as well

http://www.ebay.com.au/itm/KNURLING-TOOL-ADJUSTABLE-HEAD-16mm-shank-/400166358963?pt=LH_DefaultDomain_15&hash=item5d2bc60fb3

The bar that holds it in the QCTP holder is 16mm high and my AXA tool holders are 14mm, so I had to mill a couple of mill off to make it fit, no biggie.

Edit:

There is another one available from Chronos in the UK

it is a bit cheaper, but by the time you pay for postage maybe not that much cheaper. I decided to buy from the local guy because he was there and I could physically look at it. On the one I bought there 2 flats milled on the top of the knurled nut so you can put a spanner on to put more pressure. I found that worked really well. The pattern I got was really consistent and I could vary the depth quite easily. I could go deepr than the knurl on my Sidchrome socket wrenches or I could do a much shallower pattern.

http://www.ebay.com.au/itm/CLAMP-TYPE-KNURLING-TOOL-MEDIUM-SIZED-LATHES-/300568229581?pt=UK_Home_Garden_PowerTools_SM&hash=item45fb4336cd

There are other places that sell the clamp type as well, from memory they go to about 1.5-2 inch diameter. If you need to go bigger, then the the push in type may be the way to go.

[Anorak Bob]

You could always make your own. I purchased most of my wheels from Blackwoods. They are made by WDS in England and cost about 30 bucks a pair.

BT

[19brendan81]

Thanks Big Shed. Do you know if the wheels that came with your tool are described as coarse, medium or fine?

I think because of the size of my job I will need a push in style knurl, and acknowledge they are inferior due to the strain they put on the lathe etc. I guess I could make my own as suggested but I really want to expedite this job.

are those wheels from blackwoods pretty good Bob?

[pipeclay]

Does the Grain have to be crushed to a particular size.
It is a fairly large diameter to knurl.
Have you considered screw cutting.

[Big Shed]

Nice looking rear tool post setup BT, how do you adjust the height?

[Pete F]

Nice looking rear tool post setup BT, how do you adjust the height?

Agree! I was also admiring the slide, very handy bit of kit that.

[19brendan81]

The size of the crush when all graining isnt that critical. Its one of those things where blokes will argue til the cows come home about the features and benefits of a crush anywhere between .5mm and 1.5mm (this is the gap between the rollers and doesnt include the depth of the knurl). Most commercial designs come with adjustable rollers, however I dont know a single brewer who uses different gaps for different brews....they set it once and then leave it. My personal preference after trial and error is for a .8mm gap between the rollers. I find that the adjustable models inevitably come out of adjustment and this is something I want to avoid as it causes changes in efficiency, which can effect the balance of your brew and ultimately give youa result you dont want...which is something I will avoid by making my grain mill with a fixed gap.

I have considered thread cutting, and it would probably work (especially with two driven rollers)...however the knurl appears to be the standard so I figured thats what I would do.

How would you thread cut pipe? With a left hand then right hand cut and a 1mm pitch? Would you use a standard 60degree bit?

[Anorak Bob]

They are good Brendan. I have purchased a number of American made wheels that are equally as good and for a third of the price. Have a search for makers like Reed, Formrol, Armstrong and Brown and Sharpe.

Having quality wheels simply rules them out of the equation if the resultant knurling isn't flash. The knurls I have work well on tougher stuff like 4140. The screws and lock "nuts" shown below are made from it.

BT

[Big Shed]

Thanks Big Shed. Do you know if the wheels that came with your tool are described as coarse, medium or fine?

I think because of the size of my job I will need a push in style knurl, and acknowledge they are inferior due to the strain they put on the lathe etc. I guess I could make my own as suggested but I really want to expedite this job.

are those wheels from blackwoods pretty good Bob?

Medium I think.

[19brendan81]

Bob those Knurls are awesome....thats precisely what I want to achieve. Is that coarse medium or fine?

P.S thanks Big Shed. I think the knurl I have at home is too fine, too blunt or both.

[Big Shed]

This is the range that LPR Toolmakers have

KNURLING WHEELS comes in Pairs 3/4 x 3/8 x 1/4 PIN | eBay (http://www.ebay.com.au/itm/KNURLING-WHEELS-comes-Pairs-3-4-x-3-8-x-1-4-PIN-/110621201014?pt=LH_DefaultDomain_15&hash=item19c1899276)

So I guess the 32 tpi will give the 0.8mm pattern.

[Anorak Bob]

Fred and Pete,

There is no adjustability. I made the knurling tool to sit exactly on the lathe spindle centreline. Same with the cut off blade. To use the knurling tool on the other Hercus ( lathe no.2 Pete) fitted with the standard cross slide, I use a height adjustable tool post. The 260 extended cross slide on the green ARL sits roughly 4mm higher than the standard slide, negating simple interchangeability of tooling.

BT

[19brendan81]

Note the .8mm gap is the gap between two 4 or 5 inch long knurled rollers, set with a feeler gauge. It is not the pitch, size, shape or depth of the knurl. All of the units I see use what assume from the info above is a medium or coarse diamond pattern knurl. The rollers spin in opposite directions which pulls the grain down through the rollers and crushes it. here is a pic.

[pipeclay]

If you are going to use Pipe you may find deflection by knurling if you use a conventional knurling tool.
If you were going to screw cut you you could hold in chuck and a centre.
The thread itself would depend on the size of cross hatch you want.
You could practice on a spare bit of material to find what fine thread suits.
You could either cut right then left,or just cut left or right and turn the job around and cut again.
The depth of the Cross hatch you want will be dependant on the final pitch you choose.

[Big Shed]

Note the .8mm gap is the gap between two 4 or 5 inch long knurled rollers, set with a feeler gauge. It is not the pitch, size, shape or depth of the knurl. All of the units I see use what assume from the info above is a medium or coarse diamond pattern knurl. The rollers spin in opposite directions which pulls the grain down through the rollers and crushes it. here is a pic.

Sorry my mistake:doh:

[19brendan81]

No problems, I should have put the pic up in the first place!