# What is needed to learn the fine art of knurling on a mini-lathe?  Is it possible?



## WobblyHand (Apr 24, 2020)

Found the thread "Easy Knurling by Conrad Hoffman".  While quite informative, I've still got some questions.  It's not clear to me how easy or hard knurling is to do on a mini-lathe.  (Like I have.)  Having seen a few threads with spectacular examples of the art, I'd like to put my toes in the water. Surely not to compete with anyone, as I doubt I could make anything that nice.  Not sure what kind of knurling tool to get, or even if there are any good options with only an OxA QCTP.  Checking down in my shop, rummaging about in the toolbox, I see that I have a 250-010, which I really hadn't examined carefully before.  Never noticed before that it has some knurling rings on it one one end.

What can I expect to be able to do with this tool?  How big a workpiece?  The wheels seem to be about 0.490" in diameter and 0.18" wide, with a pivot spacing of 0.53".  How do you start?  How is the tool placed?  It looks like you have to press it into the work and also feed it.  How on earth do you maintain the right pressure?  What materials could I knurl, I'm guessing only aluminum or brass.  How do you feed it and maintain the pattern?

On the other end of this tool is a slot with set screws that is 0.509" high.  Is there a scissors or clamping knurling tool available with a 0.5" high shank?  What should I be looking for?  Classic newbie question, "where do I start?"


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## Nutfarmer (Apr 24, 2020)

Scissor or clamping type knurling tool out less strain on the lathe than the old style direct pushing style. It's important in the smaller sized lathles . Second most important item is use a quality set of knurls. The import one's will drive one crazy. Search past posts . There have been some excellent recommendations. There have been discussions of the proper dia .of the work piece to knurl. I have never bothered to match knurl  pitch to work dia. and haven't had a problem. Lastly use lots of heavy cutting oil. Above all just go make some and see what will work for you and your particular lathe


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## Cadillac (Apr 24, 2020)

Two problems I've found with the knurled you speak of. First is the force it takes to knurl like said its a lot of pressure on a small lathe but it can work. Two the axles that the knurls ride on are terrible. Sloppy fit to wheel and wear easily. I ended up replacing the axles with shoulder Allen bolts that were a snug fit to knurl wheel size. It did help a lot and it does produce a good knurl now but still a lot of force on lead screw. Since then I've made a pinch style knurled which works 100 times better with minimal forces on lathe.


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## WobblyHand (Apr 24, 2020)

A lot of folks here have much heavier lathes than I have, so what they do may not apply to me.  Am I just looking for a clamp knurling tool with a 1/2" tall shank?

Thanks, @Cadillac I did notice the wheels were quite sloppy.  They rock on the axle, not good.  I don't have a sense on how hard to push, but I guess I'll try it and see when everything stalls.  It sounds like a 3 ring circus for a beginner - lube, keep up the pressure and feed.  Shoot, I can barely stand up and run one handle on the lathe.  I may have seen someone's write up on a clamping design.  Was that yours?

With the dinky knurler that I have, how large a piece can I knurl?  Should I use a center?


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## royesses (Apr 24, 2020)

The mini lathe is capable of knurling. LMS sells a knurling tool made for the mini lathe. It typically does ok on aluminum and brass. I also knurl steel but you need to make multiple passes until you get the depth you want. The problem is the knurling tool is not extremely rigid, and the lathe is not extremely rigid. I purchased a scissors type from Travers machinery and modified it to work on my mini lathe but it requires the extended cross slide kit from LMS. So yes the minilathe can do knurling and it does a pretty good job of it.
These fit and work:  








						Scissors Knurling Tool | Hand Knurling Tool
					

Designed specifically for the mini lathe, this knurling tool fits 4-way and quick change tool posts and includes three sets of knurls. Order online today.




					littlemachineshop.com
				











						Knurler, Large Capacity with 6 sets of Knurls 3770
					

Lathe Tooling 3770 0 to 2" diameter capacity; Fits standard 4-way and quick change tool posts; Three sets of diamond knurls; Three sets of straight kn...




					littlemachineshop.com
				





This one requires modification and an extended cross slide








						TTC Quick Acting Clamp Type Knurling Tools
					

Make Perfect Knurl Patterns with TTC Quick Acting Clamp Type Knurling Tools. The quick-acting clamp-type knurling tools from TTC offer long-lasting performance. They allow for a faster setup so that you can readily start working with them. Their rugged construction and scissor-type knurling...




					www.travers.com
				



55-530-021	TTC	KT/Q/2-6	Left Hand	0 - 2-1/4"	Manual Lathe Shank	1/2"	1/2"	 $79.49 EACH	

Roy


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## WobblyHand (Apr 24, 2020)

Roy, LMS isn't currently open, due to being considered non-essential by the state of California.  (Just checked their website.)  It would be nice to give them some business, but can't honestly say there is a desperate need to knurl.  It's not an emergency (for me).  I do like the extended cross slide!  That's a good idea.  I had a devil of a time machining a 3.75" diameter piece, as I couldn't back away far enough.  Ended up angling the compound rest as far outbound as it could go.  It was pretty awkward.

I'll check out the Travers link.

At one time, I downloaded the Camjack knurler instructions.  I'll dust that off and see if it's possible to use.


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## mikey (Apr 24, 2020)

My Sherline lathe weighs just over 30# and has 0.080HP and knurls like a beast - full depth knurls in stainless, brass, aluminum and mild steel in a single pass - if you use the right tool. I'm finishing up an article on how the tool is made if you can hold on. I'll include a sort of minimalist knurling primer and that might help answer some of your questions. The bottom line is that for a small lathe, a straddle knurler is the way to go.


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## WobblyHand (Apr 24, 2020)

@mikey, thank you very much!  I'll wait.................................. 
Looking forward to this!


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## mmcmdl (Apr 24, 2020)

Get a biggin and mill the shank down . The shank means nothing other than if it fits your holders . Eagle Rocks or homemade scissprs work great in a small lathe . You need good quality knurls and axles .


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## WobblyHand (Apr 24, 2020)

@mmcmdl yes, that would work.  Don't have a mill, so it would be a little harder, but not impossible.  Files are amazing.  Guess the key is 1) scissors type, and 2) not too long for my little lathe and 3) good axles and knurls.


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## Dhal22 (Apr 24, 2020)

WobblyHand said:


> @mikey, thank you very much!  I'll wait..................................
> Looking forward to this!




Me too.   I have a little lathe....


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## savarin (Apr 24, 2020)

WobblyHand said:


> At one time, I downloaded the Camjack knurler instructions.  I'll dust that off and see if it's possible to use.



I made one of those and swear by it.
I would think that for the mini lathe it should be made a little bit smaller but maybe just the shank to fit your holder.
My lathe is only a 9x20 and I regularly knurl stainless with the camjack knurler.
I dont worry about diameters just use more clamping pressure.
heres a stainless example


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## WobblyHand (Apr 25, 2020)

For reference purposes, I am linking @mikey's post here.  It's an interesting read.  Straddle knurler.  I hadn't realize Mikey had posted it.  Found it looking for something else on HM.  Thanks so much for putting in the effort to documenting this.  Guys, Mikey's a fantastic writer!  A real HM treasure.

Enticing as all get out, hard for me to imagine building it without a mill.  Heck, even with a mill, it would take me a while!  Temporarily discouraged, knurling seems further away than I had hoped.  Dunno, I'm going to reread the straddle knurler thread again, and the camjack.  Maybe there's some knurler thingy I can make in my crappy shop with rubber screwdrivers, wobbly files, wooden wrenches and stone mallets. Feeling a little , hope to get over it soon.

Taking apart the 250-010 I do have, reveals shoulder bolts, it's just that it's a relatively sloppy fit between the bolts and the knurling wheel. Measures out to 0.192" ID for the hole, and 0.182" OD for the bolt.  There's a burr on the bolt surface as well.  Don't think I'll play with this much more.  Rather look into making something better than the 250-010.


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## royesses (Apr 25, 2020)

If you want a clamp type knurler Amazon has many of them as low as $24.95. Most are exactly like the LMS knurler. The  250-010 is a bump knurler and is usefull only for soft metals as you have found out.

Roy


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## WobblyHand (Apr 25, 2020)

Roy, I see lots of them there.  Any that you might recommend?  It's not like one can trust the reviews there.  Some folks think everything is garbage, others accept all kinds of crap.  There's a mini V type, a floating clamp type, a simple screw type.  I don't see any with significant mechanical advantage.  I'd think that would be necessary.


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## mikey (Apr 25, 2020)

WobblyHand said:


> Enticing as all get out, hard for me to imagine building it without a mill.  Heck, even with a mill, it would take me a while!  Temporarily discouraged, knurling seems further away than I had hoped.  Dunno, I'm going to reread the straddle knurler thread again, and the camjack.  Maybe there's some knurler thingy I can make in my crappy shop with rubber screwdrivers, wobbly files, wooden wrenches and stone mallets. Feeling a little , hope to get over it soon.



Please don't be discouraged. Where there is a will, there is a mill! Someday, one will fall into your lap and things will progress from there as they should. 

If I were you, I would buy a knurling tool for now and make a better one if/when you get a mill. I suggest you get this type and avoid this type. 

Regardless of which tool you end up with, see if you can improve the rigidity of the tool and it will work better for you. Of course, if you need help, sing out and we'll try to help you along.


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## WobblyHand (Apr 25, 2020)

I hope a mill doesn't land in my lap!  They're heavy!  One day...  

For the "this type" I see a LH tool.  The shank is on the wrong side.  Don't I need a RH tool?  I couldn't find a RH TTC knurler.  There is none on the travers tool website.  The Eagle Rock has a RH tool, but it's over 3X the cost.


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## mikey (Apr 25, 2020)

Give Travers a call and clarify the tool configuration. I'm not sure but the pic might be reversed. In any case, call first.


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## WobblyHand (Apr 25, 2020)

mikey said:


> Give Travers a call and clarify the tool configuration. I'm not sure but the pic might be reversed. In any case, call first.


On the Travers website, the TTC tools are only in LH version.  The Eagle Rocks show in both RH & LH.
Which one do I want, the RH?


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## mikey (Apr 25, 2020)

Yeah, the tool should face the chuck and the shank should be on the right side of the tool. I cannot imagine Travers not selling this tool in the normal configuration. I would call to confirm. 

It is also possible that the tool shank can be converted for use on the other side of the tool. My Eagle Rock knurler can be be converted to work in the rear-mounted position so maybe their tool can, too.


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## royesses (Apr 25, 2020)

Here is one with a 5/16" holder for $29.95:





						Spring Loaded Clamp Type Knurling Tool 2" Inches Capacity 5/16" Shank for Lathes - - Amazon.com
					

Spring Loaded Clamp Type Knurling Tool 2" Inches Capacity 5/16" Shank for Lathes - - Amazon.com



					www.amazon.com
				




This one is $24.95:





						2" Capacity Knurling Tool 5/16" - 8mm Shank to Hold in Quick Change Tool Post - - Amazon.com
					

2" Capacity Knurling Tool 5/16" - 8mm Shank to Hold in Quick Change Tool Post - - Amazon.com



					www.amazon.com
				




I'm assuming you have a QCTP? you can use up to 1/2" holder with a 0XA QCTP. The original tool post on a minilathe is made for 5/16". I'm suggesting not buying the more expensive ones since you will most likely want to make your own when you have the equipment.

These should do what you want and give a decent knurl.

Roy


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## WobblyHand (Apr 25, 2020)

Yes, I have an OxA QCTP.  Thanks!  Can I just use a 250-001 normal holder?


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## royesses (Apr 25, 2020)

Travers only has one knurler with a 1/2" shank, it is the one I linked to in my first post. It requires the extended cross slide kit and I had to make a new shank with the pivot moved to the end and a new pivot bolt (I have 6 or so of them with ground grip and large hex key head) and I made a bronze bushing/ sleeve as the pivot bore was too large. The knurler is quite massive for the minilathe but does a good job. It has what seems to be tapered pinned axles so changing out the wheels might be requiring more modification. Here are some photo's of it. The bolt and 1/2" square bar are part of the modifications along with a bushing. A mill is not needed to do this, just a lathe and maybe a reamer. Drilling the bushing and honing with sandpaper wrapped around a 1/4" rod would also do the job of fitting the bolt/bushing.






Roy


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## royesses (Apr 25, 2020)

WobblyHand said:


> Yes, I have an OxA QCTP.  Thanks!  Can I just use a 250-001 normal holder?


Yes, just the standard holder is all you need. If you prefer you can choose one on Amazon that has a 1/2" shank. Either one will work. Most of the knurlers Amazon has are exactly the same as LMS.
When you knurl make sure to use plenty of oil. Mikey and the machinists know a lot more about knurling than I do so I think they will give you lots of tips. 
I included the photos of the Travis knurler just to give an idea of the size and the modifications required. I am not suggesting you go that route. I think Mikey's design is the best I've seen.

Roy


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## mikey (Apr 25, 2020)

Thanks, Roy. I think the Eagle Rock design is a good one but it relies on mass for rigidity and stiffness. The key to improvement is to make sure the joint between the arms is free of play so the arms can't move too much. I like the Eagle Rock knurler but it won't fit on my Sherline and mine is stiffer, anyway. Thank you for your kind words regarding the design. I kinda like it, too.


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## royesses (Apr 25, 2020)

Yes Mikey I agree about the eagle rock design. I didn't want to design my own at the time so I went with the beefiest one I could find. As soon as I get the chance I'm going to steal your design and make one.  The one I have is able to turn the QCTP on its mount if too much pressure is applied. It will also stall out the lathe motor. 

Roy


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## mikey (Apr 25, 2020)

royesses said:


> Yes Mikey I agree about the eagle rock design. I didn't want to design my own at the time so I went with the beefiest one I could find. As soon as I get the chance I'm going to steal your design and make one.  The one I have is able to turn the QCTP on its mount if too much pressure is applied. It will also stall out the lathe motor.



It looks like your cross slide will allow you to rear mount a tool. Have you considered making a solid rear mount for your scissors knurler? It might just work well enough to avoid having to make a tool, especially if you can improve the hinge joint. If you can do that, I would go that way myself. 

I made my knurler because there was nothing out there that would fit on my lathe that was any good. The Sherline lathe only has 0.08HP but when the belt is in the low speed position, all the torque from the motor is available at low speed so my knurler will work amazingly well. Blew me away the first time I made a 90% knurl in 303SS in a single pass. Now I just assume, somewhat arrogantly I admit, that it will just work that way. I cannot knurl hard stuff in a single pass but I can do it on most common hobby shop stuff so ... good enough.


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## royesses (Apr 25, 2020)

mikey said:


> It looks like your cross slide will allow you to rear mount a tool. Have you considered making a solid rear mount for your scissors knurler? It might just work well enough to avoid having to make a tool, especially if you can improve the hinge joint. If you can do that, I would go that way myself.
> 
> I made my knurler because there was nothing out there that would fit on my lathe that was any good. The Sherline lathe only has 0.08HP but when the belt is in the low speed position, all the torque from the motor is available at low speed so my knurler will work amazingly well. Blew me away the first time I made a 90% knurl in 303SS in a single pass. Now I just assume, somewhat arrogantly I admit, that it will just work that way. I cannot knurl hard stuff in a single pass but I can do it on most common hobby shop stuff so ... good enough.



Yes I've looked at that before. It's one of the projects that I want to make soon. Since I installed tapered roller bearings and tapered gibs on the carriage I've had no problems parting so I kind of put some projects on the back burner. It would be nice to see the knurl pattern better though. 

At one time I was going to buy a Sherline. I know they are great little machines, higher quality than the Siegs. I installed a reduction pulley on my minilathe so I get about 30% more torque. It does what I need but could use more power. I think your skill plays a big part in the capabilities of that little lathe.

Roy


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## mikey (Apr 25, 2020)

If I had your lathe, the first two projects I would make would be a rear mounted parting tool post and a rear mount for a knurler. The performance boost from rear mounting has to be experienced to be believed. If you think you can part now, try a rear mounted parting tool and you'll never go back to the front, Roy.

The Sherline lathe is tiny and you have to learn to work with it. The key reason I think it is a really good small lathe is the precision of the leadscrews and not so much skill. No kidding, I can literally cut what I dial in on that lathe. I can't do that even on my Super 11 so when I need precision, I go to the Sherline. Who knew?

I really think that most lathes can be improved with the right tooling. To get that tooling, you often have to make it but hey, that's what we do, right?


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## royesses (Apr 25, 2020)

On my todo list Mikey. I have looked at both and yes they can be done.

I wish my little lathe had a dial it in lead screw like the Sherline. I think mine is graduated in quarter inch lines with 1/2" accuracy.

You bet making tooling is the fun part of this hobby. With this forum and guys like you helping everything is doable.

Roy


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## WobblyHand (Apr 26, 2020)

Looking at @mikey's thread, I think it's possible for me to make nearly every piece on a lathe, or drill press, except milling the slot in the arms.  If I buy ground stock, then at least the pieces will be darned close in size.  The side pieces will be very close.  I can clamp pieces together and drill them.  Still puzzling over the best way to do the slotted arms, but I sure can drill them together, with overlapping holes, and file them together.  Not as precisely as with a mill, but it's possible.  The half moons won't be able to be a true half moon, but I could get close machining them using a 4J chuck.  Should be good enough.  Not quite sure about rear mounting, but I think doing so would be a very good thing.  I have a big enough chunk of aluminum to do that.

For some more detailed questions on straddle knurler, should I ask here, or on the other thread?  I'd hate to clutter up that beautiful post.  My questions are on topic for this post.  For instance, for the knurling pins, what is special about the Precision drill rod? Instead, could I use hardened O1?  Or M42 rod?  If I used the M42 rod, I should be able to cut it with an abrasive saw disk without worrying about softening it, right?  I mean, it's cobalt steel.


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## mikey (Apr 26, 2020)

First, your questions are appropriate in either thread but since this one is yours, ask your questions here. 

If you work very carefully, you probably could make that knurler without a mill. Before I had a mill, I had a hacksaw, files and a strong right arm. 

If you buy ground low carbon steel, much of the machining will already be done for you. The plates and arms will be precision ground, straight and flat. None of the dimensions in that tool are so precise that you can fudge the pieces one way or the other. 

For the half-moons, use round rod that is accurate; O-1 rod works well for this because it is somewhat hardened as supplied and it works fine for the wear it will see in that state. Hardening is not necessary. The problem will be cutting them in half to form the pivots - maybe ask one of the forum guys to do this for you? Whatever you do, do not grind this stuff in half; it will be harder than Hades and you won't be able to drill or tap it.

For the pins, nothing special about the brand (PTD) but I suggest you use a drill blank. It is precisely sized and hard enough to use as a pin. 

For cutting the slots in the arms for the wheels, you can do this several ways. You can scribe the slot on both sides and bandsaw or hacksaw out most of the bulk, then file it to your layout lines. I remember doing fairly precise filing this way. Or you can ask one of the guys on the forum to end mill it for you, which would be the easiest way. 

Otherwise, I don't see a major obstacle if you have a lathe, a drill press and the will. If you do build it, maybe take pics and start a thread. I'm sure there is some other hobby guy out there in your shoes, too.


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## WobblyHand (Apr 26, 2020)

@mikey Thanks for the encouragement.  Been scratching my head trying to make this happen.  Even made out a shopping list.  Yes, I was planning on using ground stock, that would help me get over the milling to exact size problem.  

For the half moons, do they exactly have to be 1/2 circles?  How about being a clipped circles?  (Almost 1/2 moons.)  I was thinking of laying the tight tolerance O1 rod on its side and holding them with a 4J and cutting a flat on them.  I'd use carbide, I guess. Would that work?  Or would that harden the daylights out of it?

For the knurl pins, could I use D2 steel?  That's a tight tolerance tool steel.  Drill rods confuse me.  Looking on McMaster, they have comments that O-1 could be used as drill rod, as well as D2, M2, well you get the idea, too many choices.  They also have some M42 tight tolerance rod as well.  It specs at -0.0002" to 0" ground finish.  ($14 for 4.5") I know M42 will maintain its hardness!   What kind of hardness is desirable?  I could get hardened O-1 for instance.

I'll try the layout lines, hacksaws and files.  After all, it's only low carbon steel, not tool steel.  Filing shouldn't be that hard.  Almost any filing is better than filing tool steel with a diamond file!  The filing will keep me off the streets, which is a good thing these days. There's a 4x6 horizontal bandsaw in the garage, but I just don't trust it enough to do this kind of work.  The vise is terrible.    

One last question, what did you use for the spring?  How long does it need to be?  It has to have an ID greater than 1/4" to fit over the tension screw, but beyond that I'm not sure.  If I had a box of springs laying around, I wouldn't even ask.  Since I need to order stuff, might as well get something close!

As for a project thread, should I start one in the Members project area?  Yes, some of us hobby guys starting out don't or can't have a full shop, so we have to substitute resourcefulness for raw tons of iron.  Maybe it  would encourage another beginner.


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## mikey (Apr 26, 2020)

WobblyHand said:


> @mikey Thanks for the encouragement.



Brother, if you have the will and determination to see this through, you can do it. I don't know about you but the best way to make sure I do something is to tell me I can't!



WobblyHand said:


> For the half moons, do they exactly have to be 1/2 circles?  How about being a clipped circles?  (Almost 1/2 moons.)  I was thinking of laying the tight tolerance O1 rod on its side and holding them with a 4J and cutting a flat on them.  I'd use carbide, I guess. Would that work?  Or would that harden the daylights out of it?



No, the half-moons do not have to be perfect halves; mine are not. However, the flats need to be pretty flat. I don't know if cutting them on the lathe will harden them excessively; you have to try it and see. I don't see why it would be much harder than using an end mill if you use a lot of cutting oil and take small bites but having never done this before, I am not sure. Try it and see.



WobblyHand said:


> For the knurl pins, could I use D2 steel?  That's a tight tolerance tool steel.  Drill rods confuse me.  Looking on McMaster, they have comments that O-1 could be used as drill rod, as well as D2, M2, well you get the idea, too many choices.  They also have some M42 tight tolerance rod as well.  It specs at -0.0002" to 0" ground finish.  ($14 for 4.5") I know M42 will maintain its hardness!   What kind of hardness is desirable?  I could get hardened O-1 for instance.



I just used a drill *blank*. You can buy these cheaply on ebay. I used PTD brand because they are known to be a quality brand but you can use whatever you like. Size them for the ID of the wheels you use.




WobblyHand said:


> I'll try the layout lines, hacksaws and files.  After all, it's only low carbon steel, not tool steel.  Filing shouldn't be that hard.  Almost any filing is better than filing tool steel with a diamond file!  The filing will keep me off the streets, which is a good thing these days. There's a 4x6 horizontal bandsaw in the garage, but I just don't trust it enough to do this kind of work.  The vise is terrible.



Filing is not hard. Filing accurately is hard!



WobblyHand said:


> One last question, what did you use for the spring?  How long does it need to be?  It has to have an ID greater than 1/4" to fit over the tension screw, but beyond that I'm not sure.  If I had a box of springs laying around, I wouldn't even ask.  Since I need to order stuff, might as well get something close!



The spring is not critical. If it helps, mine is 1-1/2" long.



WobblyHand said:


> As for a project thread, should I start one in the Members project area?  Yes, some of us hobby guys starting out don't or can't have a full shop, so we have to substitute resourcefulness for raw tons of iron.  Maybe it  would encourage another beginner.



Yup, start a thread there. I guarantee you that there is some silent guy out there with fewer tools and experience than you that will benefit from everything you share. I think this is a good project for this kind of effort because most of the dimensions are non-critical. In fact, none of them are critical but you need to try for good fits where you can. In the past, guys who made things mostly by hand were called Craftsmen ... not a bad label if you ask me.


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## WobblyHand (Apr 26, 2020)

@mikey Alright, one last question on drill blanks.  The link you provided has a lot of listings.  What's in common is they say 3/16", which to me is 0.1875".  However, they seem to be all different diameters?  Right off the bat, I see, .1770, 0.1600, .1760, 0.1910, 0.1660, and 0.2010.  Why are they different diameters and not just 0.1875?  How does this work?  Confused.

Are they machined or brazed onto other tooling?  Why is 3/16 drill rod not 3/16?  What kind of tomfoolery is this?

Don't get me wrong, I understand that I'd get something that was dimensionally closest to what I need.  I'm just used to ordering things with a tolerance that I understand.  Mind is flabbergasted that 0.1600 is called 3/16.  Is this weird dimensioning also in other parts of machine technology?  Or is this eBayese?


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## mikey (Apr 26, 2020)

It is Chinese-ese. Look for blanks made in the US or with a stated tolerance. Drill blanks are normally +0.0000, - 0.0003" or something like that. If in doubt, order from McMaster Carr; they will give you dimensions and you'll get a quality product.


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## WobblyHand (Apr 26, 2020)

Oh, thank goodness, thought I had gone insane!  There weren't any PTD drill rods in good sizes today on eBay.  Might have to shop on $$$ McMaster.  I'll get something. 

One thing I don't quite understand is if one should get a hardened rod, or just "drill" rod from a reliable supplier.  McMaster really confused me with multiple steels qualifying as drill rod, especially since they were available as either hardened or annealed.

Edit: Formroldie sells carbide pins, so clearly they think hard is good.  Might go with hardened pins then.


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## mikey (Apr 26, 2020)

You are looking for drill *BLANKS*, not drill rod. Drill blanks are hardened to about Rc60 and are precisely sized.


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## royesses (Apr 26, 2020)

My LMS straddle knurler wore the original pins a lot so I made some out of 4130 - fail lasted a couple of knurls and started wearing. So I made some out of 4140 and heat treated and tempered to 52 Rockwell and they are doing much better. I may also go the carbide pin route. I wonder how well the drill blank pins will last. That might be a good way to go also. I think Mikey just answered my question 60 Rockwell.

Roy


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## WobblyHand (Apr 26, 2020)

mikey said:


> You are looking for drill *BLANKS*, not drill rod. Drill blanks are hardened to about Rc60 and are precisely sized.


Oh, I missed that.  *Thanks for whacking the 2x4 on the side of my head!*  So RC60 and harder.  That helps a lot!  Still a few choices, but it narrows down the field.  Thanks for your patience.  All the 'rod' I was looking at was precisely sized, I was missing the hardness spec.  Now that I have that, the shopping begins...


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## WobblyHand (Apr 27, 2020)

Two more posts on this thread before transitioning to a project thread.  Wanted to test cutting the half moons on the lathe.  Chucked a small piece of 5/8" O-1 in a 4J.  (That's what I had.)  Cut a flat on it.  Used a TCGT carbide insert for this.  Despite the interrupted cut, everything was good except two corners which chipped.  Probably should have used a new edge on the insert for this, but I was lazy.



4J marks are on the two ends and on the sides, they are not near any bearing surfaces.  The circular grooves on the face were a little deeper than expected, but I can hone them to any degree of smoothness.  Honing annealed O-1 is a piece of cake compared to HSS.  After I make it prettier, I'll try drilling it.  Not expecting that it's worse than any other O-1.

Contacted Form Roll Die for the knurling wheels.  Not sure they want to sell to a hobbyist.  We'll see.


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## Maplehead (Apr 29, 2020)

savarin said:


> I made one of those and swear by it.
> I would think that for the mini lathe it should be made a little bit smaller but maybe just the shank to fit your holder.
> My lathe is only a 9x20 and I regularly knurl stainless with the camjack knurler.
> I dont worry about diameters just use more clamping pressure.
> ...


Now that I have a 9x19 I'd consider trying knurling again if I could get them as good as these examples. Great job.


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