Hemingway Sensitive Knurler?

[donf]

I have had my 8x12 import lathe since 2007. It replaced my Atlas 6” lathe and I think I made the right choice on which lathe to keep. There were some much better things about the Atlas though. It’s mostly been a bushing maker / bolt shortener, etc.

I want to start using it more and leaning more skill with it. I have two import bump style knurlers and they worked OK until I tried steel instead of aluminum a few weeks ago. It’s a good thing all I wanted was to roughen up a tube to use as a handle because it’s ugly!

I read past posts here and know I know that I need to upgrade to a scissor knurler. I was all ready to buy the Sensitive Knurling Tool kit HK 1115 from Hemingway a few weeks ago for $60 until I got shocked with the $74 shipping charge! I inquired to Hemingway to see it this was correct or to see if I could just buy the plans (no use shipping chucks of metal across the world when a metal supply yard is 15 minutes away)…after a few weeks and no response I can safely say than my inquiry was ignored!
So it might be time for plan B. I could buy a knurler, but I would rather build one and learn at the same time.

My questions are
1) For those that have built the better Hemingway kit, was it good enough to warrant the $130 including shipping to get just metal and a paper plan? I don’t mind spending money but I’m not wealthy so I don’t want to throw it away either!

2) What’s the lever on the top arm do? The better knurler Hemingway offers is a copy of an older English design, but I tried searching to see if I could see pictures of one disassembled to better understand what its purpose was.
I also looked at the basic knurler and it seems to use a very small knurl wheel, not the 3/4-3/8-1/4 that's most common here.

3) I could just use a different plan. I have found several free plans online to look at and some look very nice, but they don’t incorporate the slider or whatever it is in the top arm. If that's important to results then I would like to see if I could incorporate that.

[JCHannum]

These appear to be nothing more than variations on the scissor knurling tool. Plans have been published in the HSM magazines and several other publications. I built the one by Rudy Kouhoupt as well as the one in one of the Lautaurd Bedside Reader books. I suspect the lever on the top is a quick release feature that does offer some benefits, but is not a show stopper.

My suggestion is to spend your money on some of the books and other publications with plans and build articles for these tools. You will get a lot more return on your dollar.

Welcome to the site.

[John Stevenson]

The lever on the top arm is an eccentric and allows you to take the load off for a return to the start for a second pass is needed.

Personally I'd look at doing your own design incorporating all the information you can get from various sources.

Draw one up and post it on here for review, your design and feedback received will learn you more than writing a cheque out.

For a starter everyone I have seen sandwiches the wheels in a slot on the arms. The result is you always have one side of the slot in the way. Hemingway quotes 1/4" which could be a show stopper if you wanted to knurl up to a shoulder.

Some of the expensive commercial units use recessed wheels so this doesn't happen but I have never seen it in a home shop environment

This is a straight knurl but you can get matched pairs for diamond knurling as well.

[Jaakko Fagerlund]

Or bite the bullet and build a cut knurling tool Manually adjustable version is a very easy to build but a little bit difficult to adjust properly, whereas a properly built will have an adjustment screw/gear in it. And with this tool you get nearly zero load on your headstock bearings etc.

[donf]

Is just a copy of some measurements on my lathe and a few pictures of Hemingway's basic knurler. I do think I will try to not sandwich the rollers in the arm that was a good suggestion. The lever for a second pass sounds handy I just don't picture what is needed design wise. A cut knurler sounds interesting too! I have to get off the computer and get some chores done before the weekend ends.
Thank you for the advise!

[John Stevenson]

Just a quick question.

Do you have to have diamond knurls or will a straight knurl do ?
The reason I ask is a cut knurler for straight knurls is very simple to build.

[donf]

I would like to do both types of knurls, but this hopefully is not my last project. So maybe I can build one type now and another type latter. I do have a little X3 mill to go along with my little lathe. Thank you for the help!

[IanPendle]

The Hemingway knurler is a copy of the original Marlco knurling tool. They come up on ebay quite often in the UK and seem to sell for around £50. I wonder if they were sold in the US? You could maybe search using Marlco?

Ian.

[willmac]

I have built the Heminway knurler and it works well for small lathes. The additional lever is useful - it provides a sensitive 'feed' of the knurl into the work as well as being able to release the knurls from the work (but retain the main screw adjustment) as John S said.

The point about the knurls running in a slot rather than being cantilevered out is valid. This can limit how close you can get to a shoulder. In addition, the knurl axis pin also sticks out a bit and can interfere. However, this is true of most small scissor knurlers and is hard to avoid if using small knurling wheels.

If I had a much bigger heavier lathe I wouldn't use this type of knurler, but for its intended purpose it is fine.

Just to illustrate what we are discussing see below for photos of mine.

[donf]

I wonder if they were sold in the US? You could maybe search using Marlco?

Thanks, I will keep a look out. I have been looking and nothing shows up currently.

I have built the Hemingway knurler and it works well for small lathes. The additional lever is useful - it provides a sensitive 'feed' of the knurl into the work as well as being able to release the knurls from the work (but retain the main screw adjustment) as John S said.

I like the design a lot, it just looks nice. I think I will try to add a release lever to my project plans as it seems to add a bit of functionality to the tool. I have thought about the offset cam and it now makes sense that the moving the arm down even slightly will release the pressure on the rollers. Does the design use a detent to hold the arm in the upper position while knurling?
Thank you for the help!