PM1340 - the Best & Jacobs Full Custom Edition

Mind boggling
Couple of questions
Where did your get the ER40 collet chuck with the D1-4
What size chuck guard did you get?

What is "mind boggling" about it? Is that a good thing, or a bad thing?

Every photo at the link I initially provided has a description of what's in the photo. Just click on the photo and the text is in a box below the image.

ER40 collet chuck specifics: https://www.flickr.com/photos/davidpbest/33457416614/in/album-72157683014913836/

Flexbar LatheGuard info: https://www.flickr.com/photos/davidpbest/32852017594/in/album-72157683014913836/
 
Thanks for your detailed reply & clear pictures.
Sidebar question (sorry I was ogling your tool rack haha). Can you tell me about your knurling tool? Is it your own design or commercial unit? Looks like a standoff integrated to the shank... so you can approach a shoulder & keep the tool post back a bit, or?

SNAG-5-8-2017 0000.jpg
 
Thanks for your detailed reply & clear pictures.
Sidebar question (sorry I was ogling your tool rack haha). Can you tell me about your knurling tool? Is it your own design or commercial unit? Looks like a standoff integrated to the shank... so you can approach a shoulder & keep the tool post back a bit, or?

Certainly. I first bought an inexpensive import scissors knurling tool from Enco: https://www.mscdirect.com/product/details/78657012?rItem=78657012

This is not a quality tool, and would have required a lot of tuning, and fixing to make it into one. I didn't have the patience to do this:


So I decided to buy a higher quality knurling tool from Eagle Rock. That's what you see in the photo. Eagle Rock makes lots of different models, right, center, left offset, etc. They're entry level version I'm sure is great, but it's not designed to easily replace the knurling wheels. I bought this one
http://specialtytooling.eaglerockon...-scissor-type-knurling-tools/k1-44-21-0625r-e

from Ajax tools for $300 http://www.ajaxtoolsupply.com/earoknscclkn2.html

I based my decision largely on this review:


The Eagle Rock is made in the USA, and is a fine tool. I wouldn't put it in the category of a Swiss watch or as refined as what Stephan did in his upgrade of an import, but it suits my needs and I can recommend it. That specific tool comes with 20 TPI diamond wheels that are 3/4" diameter, 3/8" wide with a 1/4" bore for the axle.

I had not knurled before jumping immediately into the deep end of the pool, taking on a heavy deep knurling of 316 stainless steel with 12 TPI wheels. These are the wheels:

IMG_5637.jpg


This is what I was making - thumb screws

IMG_5729.jpg


for the sliding cover over the compound DRO scale:

IMG_5738.jpg


That was challenging. And I'd put it at the limit of the 1340 lathe without moving to a solid tool post (eliminating the compound) which I intend to do soon. Jbolt has a thread that discusses the solid tool post mount here on H-M. as well as YouTube videos by Stefan

(
)

and Robin

(
).

The biggest problem I've found with knurling is that under heavy load, the tool post (Dorian in my case) will tend to drift clockwise - which really chowders-up the knurling. Tighten everything down, lock the cross slide, and use cutting oil.

More conventional diamond cutting 20 TPI is much easier on the machine. Here's a video of that operation - making the handles and knobs for the 1340 out of 316 Stainless:
https://www.flickr.com/photos/davidpbest/34162064130/in/album-72157672547607804/ The handles, took several passes at progressively deeper cuts, and it was important to get the OD on the part matched to the TPI of the knurling wheel to get good results.

I ended up making a spreadsheet for looking up the required OD for the TPI knurling wheels I have on hand (12, 20 and 21) and I'm attaching it here - look for the OD you are targeting, and to the right will be the precise OD that comes closest to the target that matches the TPI of the wheel.

Hope this helps.
 

Attachments

  • Knurling Diameter Calculations 12 20 21 TPI.pdf
    34.8 KB · Views: 331
What is "mind boggling" about it? Is that a good thing, or a bad thing?

Every photo at the link I initially provided has a description of what's in the photo. Just click on the photo and the text is in a box below the image.

ER40 collet chuck specifics: https://www.flickr.com/photos/davidpbest/33457416614/in/album-72157683014913836/

Flexbar LatheGuard info: https://www.flickr.com/photos/davidpbest/32852017594/in/album-72157683014913836/

In a good way. I can't imagine doing as much as you did in the year or so that you had the lathe.

I was considering the Pratt Burnerd Multi-size collet system but a chuck and set of collets would run about have the cost of the lathe.

Thanks again for all your help
 
+1 on the Eagle Rock K-144. I have the K-201 that uses press pins to hold the knurls and its a pain to change the wheels.
 
David, I just re-read your build thread again and I'm not sure if can express how much I appreciate the work you have done, both on the machine and the work to post it here for others to learn from and admire, thank you.

I noticed on your VFD enclosure I didn't see any fusing on the incoming power, how did you handle that?

David.
 
I didn't put fusing on the VFD end because I didn't see the need. What would fusing there be protecting? The power for the VFD is on a dedicated 3-phase branch circuit with a breaker at the load center that will protect the wiring from any overload generated at the VFD end. Since the VFD is the only thing on that branch circuit, the possibility of some other element creating some kind of voltage condition that would damage the VFD is eliminated. So I scratched my head and asked "if I put fuses here, what would they be protecting and from what condition" and I still do not see their purpose if I had included them. I asked around and the best answer I got as to why to put fuses at the VFD end was "everybody does it that way" or "it's code" (which isn't true), or "to protect the VFD" to which I ask "from what?" and got no answer. So you tell me - maybe I'm missing something. What would fuses at the VFD end be protecting that isn't already protected by the breaker at the load center?
 
OK good answer, I'm certainly not qualified to comment on why not have fuses installed before the VFD.

I'm using them in my install because Mark (mskj) included them in his wiring diagrams he sent me and now that I've purchased them they will be installed.

Also Mike from Zmotorsports also included them on his install, so I just followed suit as I don't know enough to question the logic of are they needed or not.

Something to do with breakers protect the wiring, fast acting fuses protect the components, I read that on one of the VFD threads at one time.

Thanks for the quick response.

David.
 
Yes, I've heard the party line that fast acting fuses protect the components. With only one load on the branch circuit, I still ask "protect the components from what? What electrical anomaly is going to occur that requires a fuse to protect the VFD if the VFD is the only device on the circuit?" No one has been able to answer that to my satisfaction. Some people wave their hands and start talking extemporaneously about "surges" and "lightening strikes" etc. and fine, if that occurs, my $300 VFD gets fried. BFD I say. LOL
 
I agree, fuses would probably be an unnecessary redundancy. If the breaker trips it will probably be because the VFD burned out.
One thing to keep in mind, if you have the machine hardwired (without a plug) directly to that branch circuit, you need a means of disconnect within 5 feet. Typically a fusebox with a switch is used.
PS Awesome Job on the lathe!!!
 
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