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S&S_ShovelHead
03-15-2011, 09:58 PM
I need to turn a peice of .6" OD SS bar, 1.5" long. Drilled and taped (3/8 X 16) all the way through. It needs to look very nice and have a grip so it can be hand tightened. Tried out the chinese knurling tool today and it was just garbage, could barely make an impression in aluminum. Im going to make a knurling tool on my mill but it wont be here untill next week and I need this job done in 5 days. Any tips on a way I can use my lathe to create a nice looking, gripable surface?

Mcgyver
03-15-2011, 10:02 PM
rig up something to index off a gear at the back, set a V tool up sideways and 'plane' a straight knurl? which a chamfer at each end these can look very clean and professional

S&S_ShovelHead
03-15-2011, 10:05 PM
Having a hard time picturing that, any pics possible?

Ken_Shea
03-15-2011, 10:16 PM
Just turn a number of very narrow grooves.

Never tried it but one suggestion read some time back was to thread RH and then thread again LH

S&S_ShovelHead
03-15-2011, 10:19 PM
Just turn a number of very narrow grooves.

Never tried it but one suggestion read some time back was to thread RH and then thread again LH

I thought about the LH + RH threading but Im not sure I could do it where it would look nice.

Also thought about a bunch of very narrow grooves but am not sure how well that would work for gripping.

Elninio
03-15-2011, 10:25 PM
Cut two large threads, one left and one right-hand, something like four or two TPI.

Mcgyver
03-15-2011, 10:39 PM
Having a hard time picturing that, any pics possible?

a straight knurl, like this:


http://media.digikey.com/photos/Keystone%20Elect%20Photos/2073.jpg

kendall
03-15-2011, 10:43 PM
Just turn a number of very narrow grooves.

Never tried it but one suggestion read some time back was to thread RH and then thread again LH

I've done it and it works well. coarse multi start threads cut shallow make for a very nice feel and good grip

johnnyd
03-15-2011, 10:45 PM
What Mcgyver said...mount your thread cutting tool sideways.
Start at one end & "scratch" a deep groove horizontally the length that you want. (hand cranking the lathe carriage)
Rotate chuck however many degrees you want, & repeat as necessary. :D

Carld
03-15-2011, 11:08 PM
What they are trying to tell you is first align the knurling tool perpendicular to the work. Then move the knurler so the knurling wheels are pointing slightly toward the tail stock. It just takes a few degrees of angle, like 2 or 3 degrees.

Knurling SS is hard to do and it takes a good knurler to do it and a little experimenting.

I suggest you take a piece of SS turned to the .6" that sticks out of the chuck about 2 1/2". Then knurl that and then drill and tap the hole then part it off.

S&S_ShovelHead
03-16-2011, 12:06 AM
I tried several of the mentioned methods but none really worked well enough. If I can get a good knurling tool locally then the job would pay for it (and Ide hate to lose the job).

Any thoughts on the tool in the top right? http://www.kbctools.com/can/Navigation/NavPDF.cfm?PDFPage=390
It looks like they have a chinese one (KBC brand) & and american (Eagle rock one) for almost triple the price.

Black_Moons
03-16-2011, 06:28 AM
Unless you have a HUGE lathe and are knurling aluminum, Yea, you basicly need the sissor type knurler, I think I got mine for like $60 off ebay. Seems to work ok. have not used it much however.. came with 3 diffrent pitch of wheels however, that was nice.

camdigger
03-16-2011, 06:41 AM
Are the knurled wheels from the chinese knurler OK? If so, there is the possibility of building a scissor knurler..... Be almost as fast as ordering one from a supply house.

firbikrhd1
03-16-2011, 09:42 AM
The scissor type tool should work well, but I have no experience with one, I just think the principal is sound. My lathe is a 10" Logan, fairly stout but certainly not a heavy lathe and I can knurl steel with a standard knurling tool like those made by Armstrong, Williams, etc. You mentioned having a tool made in China and it may be the problem, or perhaps the wheels are dull/soft. Something you might try with your current tool is adjusting it so it meets the work at an angle less than 90 degrees, i.e. allowing the edge of the tool closer to the tailstock to apply more pressure than the edge toward the headstock. This slight angle will apply more point pressure and possibly allow you to obtain a good knurl.

Toolguy
03-16-2011, 10:18 AM
I have 2 of the Eagle Rock ones, the scissor or plier type, one goes up to 2 inches and one goes up to 6 inches. I use them fairly often and they work great. I will not use the push or bump style - that puts a huge amount of wear on the leadscrew and especially the bronze leadscew nut. Good quality knurls are a must, but good ones needn't be expensive.

Westline
03-16-2011, 10:24 AM
I Think we are running a bit off topic here trying to fix the OP's knurling style and not giving him alternatives to knurling..... but hey what the heck I'll bite.
firbikrhd1 has a good point by providing the same pressure but on a smaller area on the work to get a better knurl.
I have done something similiar that worked well for me.
When the knurling tool does not make a nice deep pattern I engage the halfnut and run the machine in Rev till it gets to the tailstock then I let 3/4 of the wheel track off the edge of the work and disengage the halfnut.
This gives it a nice small area to apply pressure too, while doing that I let the lathe run and keep on cross feeding the tool in towards the work without forcing it too much. I don't like applying to much force on my crossfeed nut.
When the knurnling tool has dugg in a bit better, stop the lathe, flip it to forward and set the feed to as slow as possible, engage the halfnut and off you go.
The knurling tool will now mostly cut with it's left edge as it get new high material, if you run the feed too fast it will climb on top of the material again and not cut into it.
I used this on hardened 4140 on my 9 x 19 lathe and it works really well.
Just remember to lock your crossfeed gib before starting to autofeed ..... no need to make your cross feed backlash any bigger:D

AiR_GuNNeR
03-16-2011, 01:03 PM
A cut type knurling tool would work well too. They are a bit pricey, but worth it. I picked one up off of eBay a while ago.

S&S_ShovelHead
03-16-2011, 02:04 PM
Tryed all the mentioned methods with my knurling tool, it still barely scratches the metal.

I cant bring myself to spend $220 or a knurling tool when I can make a better one in a week or so.

Came across this idea http://i150.photobucket.com/albums/s120/torchroadster/DSC04851.jpg

Made a prototype out of aluminum and the client liked it so now I have 16 more to build. Any tips on an adhesive that will prevent the o ring from spinning. I got some gasket maker on one right now to see if it will hold but dont have high hopes (just what I had lying around).

Toolguy
03-16-2011, 02:11 PM
Use smaller o rings for a tight fit. No glue needed.

Carld
03-16-2011, 02:26 PM
RTV in the grooves and put the O ring on then wipe off the excess. Cheap and fast and permanent. The good thing is he can replace the O rings if they get damaged or wear and you can't do that with a knurl.

Mcgyver
03-16-2011, 02:30 PM
thanks thinking out of the box - good solution

S_J_H
03-16-2011, 02:49 PM
I need to turn a peice of .6" OD SS bar, 1.5" long. Drilled and taped (3/8 X 16) all the way through. It needs to look very nice and have a grip so it can be hand tightened. Tried out the chinese knurling tool today and it was just garbage, could barely make an impression in aluminum. Im going to make a knurling tool on my mill but it wont be here untill next week and I need this job done in 5 days. Any tips on a way I can use my lathe to create a nice looking, gripable surface?
Knurling does take a little time to learn so practice on scrap for a while.
SS is tricky stuff as you constantly have to think about work hardening.

The simple non scissor, push knurlers work fine in aluminum using tailstock support. IMO they can actually do a better job in some cases as they are more rigid. But yeah like everybody says they are hard on the machine.
I made this shifter knob long ago on a little 7x10 using a simple push knurler that cost about 20$-
http://i109.photobucket.com/albums/n48/S_J_H/032Shifterhandle1.jpg
http://i109.photobucket.com/albums/n48/S_J_H/033Shifterhandle2.jpg

Now a days I pretty much always use the scissor type of knurler.
I bought this import one from Enco for about $60 on sale-
http://www.use-enco.com/CGI/INSRIT?PMAKA=505-4518&PMPXNO=950782&PARTPG=INLMK3

It's not the prettiest knurler, but it has worked pretty good and the knurl wheels that are included seem to work OK with 303 stainless.
A lot of guys make their own scissor knurlers and some are mighty impressive looking and make for a real nice project.

I like the look of the groove & o-ring. Does it give enough grip for what your making?

Cutting the 1.5" long internal 3/8"-16 thread in the SS might be a bit of a PITA.
What method and tools are you going to use?
Steve

S&S_ShovelHead
03-16-2011, 03:48 PM
I like the look of the groove & o-ring. Does it give enough grip for what your making?

Cutting the 1.5" long internal 3/8"-16 thread in the SS might be a bit of a PITA.
What method and tools are you going to use?
Steve

The grip should be good enough, I hope.

I was just going to use a taper tap and try to aim for 55-60% thread engagement. Last time I tried to tap SS it did not go well so any tips to make life easier would be appreciated.

MotorradMike
03-16-2011, 04:39 PM
Came across this idea

Very nice.
I'm stealing that.

About tapping:
I had trouble with SS until I spent real money on an American tap. Then it went very well. I believe it was 302 SS though, one of the easy ones to work with.

Peter N
03-16-2011, 04:55 PM
...... so any tips to make life easier would be appreciated.


Yep - use 303 stainless everytime and life will be much easier:D
As it happens I had a little project recently very similar to yours that required both knurling and tapping some stainless.

I made this.
It's a 12.77mm (0.502") bush with an M10x1.25 left-hand thread. It's cut off at 15mm length, but was turned/knurled/tapped over 30mm as I thought I might need a spare one, but it actually came right first time.


http://www.btinternet.com/~p.neill/Coffee/InsertKnurl.jpg


Just to add to the bragging rights I didn't have an M10x1.25 left-hand tap, so I made one:


http://www.btinternet.com/~p.neill/Coffee/LHTap.jpg


And just in case you wondered what it was for, it was to repair this.
This is a rare plastic-reservoir master cylinder from a 1975 RD350 Yamaha, that has the L/H mirror mounting thread integral in the casting. Which as you can see is a bit of a mess.
I made the insert so that I can drill & ream the casting to 0.500" and then press fit the insert in place. The knurl is to prevent it rotating when the mirror is screwed in.


http://www.btinternet.com/~p.neill/Coffee/Mastcyl.jpg


I haven't yet had time to fit it though, work keeps getting in the way of playtime.
When I tapped the stainless I used some Rocol RTD, which is a dark sulpherised cutting oil. Using 303 and this stuff will make your life much more stress free.

Peter

John Stevenson
03-16-2011, 05:47 PM
Bit OTT but a while ago got an order to make some alloy rollers 30mm diameter 60mm long with a straight knurl and an eccentric hole in them.
They were for laundry machines that as the frame with these on revolved the roller would spin round on the eccentric and trap a towel / sheet etc and drag it thru the machine.

Real NASA high tolerance work. :rolleyes:

So banged a straight knurl on and sent them out and they got returned with a sample and told the knurl need to be straight ? Ok it was pretty straight but it would still do the job, the sample which I had never seen before was absolutely perfect, looked more like milled teeth than knurled ? ! light bulb moment.

Had a hunt round and found a splined hob I had bought off Ebay because it was cheap, blued a bit of 30mm bar up and rolled the hob round it and counted teggies.

Set the hobber up and hobbed three lengths of bar at about 15" long each, dead fast and purfect.

Here's a bit that was left.

http://img.photobucket.com/albums/0903/registered_user/hobbedknurl.jpg

MotorradMike
03-16-2011, 05:56 PM
Had a hunt round and found a splined hob I had bought off Ebay because it was cheap, blued a bit of 30mm bar up and rolled the hob round it and counted teggies.


I know you're from the UK and all but please do speak English.

John Stevenson
03-16-2011, 05:59 PM
I know you're from the UK and all but please do speak English.

It is English - teggies
If I came from North Carolina it would be tooth ;)

jugs
03-16-2011, 07:00 PM
I know you're from the UK and all but please do speak English.

A up lad, wats thee bletherin at, appen tha knows nowt about tit.
By 'eck! tha's askin for a reet braying.

As me gran ud say -

"If tha knows nowt, say nowt an-appen nob'dee 'll notice."

Git tha's sen lernin
http://yorkshirefolk.myfineforum.org/archive/yorkshire-colloquialisms__o_t__t_74.html


john
:)

S&S_ShovelHead
03-20-2011, 08:28 PM
Finished up the parts. The o-rings turned out well and the gasket sealer I originally used to secure them worked very well (I tried without it but friction alone didnt cut it). These are used by inserting the nut end through a key shaped hole and turning the cylinder to secure it in place, createing a mobile mount via the rod end. I was wondering what an average ballpark price (labour only) would be for a machinist to make theses four parts and drill/tap the aluminum mount. I was thinking around $150-200 canadian.

http://i1198.photobucket.com/albums/aa457/Shea_G/P1000087.jpg
http://i1198.photobucket.com/albums/aa457/Shea_G/P1000084.jpg