Precision Matthews BS-1 Dividing Head Full Review and How to Use Part 2

[BladesIIB]

In this video I used the term Differential Indexing incorrectly, what I call Differential Indexing is actually Plain or Simple Indexing. The formula is correct for Plain/Simple Indexing. My apologies for giving it the incorrect name.

In Part 2 of this review I make a couple of chess pieces then put the dividing head into action for Plain/Simple Indexing and Direct Indexing. It Performs Flawlessly - and better than me!

Also intro the concept of using a formula to get CNC like repeatability from your DRO. Was to much to get into detail in this video so look for a video to help maximize the DRO on your lathe next Saturday morning.

This video is broken down in sections and the direct links are in the YouTube description.

Discuss Project (chess pieces) - 3:05
Grind Custom Tool - 4:45
Machine Two Chess Pieces - 7:40
Plain/Simple Indexing on The Mill - 15:20
Direct Indexing on The Mill - 23:10
Finish Chess Pieces - 31:10

All Lathe work is done on a Precision Matthews PM 1440TL Lathe.
All Mill work is done on a Jet JMD-18PFN

 

[benmychree]

What you call differential indexing is not differential indexing. True differential indexing is where, through a train of gears, the spindle of the dividing head is geared to the index plate of a universal dividing head, so that when the index crank is turned, causing the spindle to rotate, the gear train feeds back to the index plate causing it to rotate, either forward or backwards. this done to allow prime numbers to be divided such as 127, the number of gear teeth required for true metric transposing on a lathe.
What you are calling differential indexing, is called by Brown & Sharpe, PLAIN INDEXING.

 

[BladesIIB]

benmychree- I appreciate the correction and my apologies for getting that wrong. I will correct the Thumbnail on this video and make a correction in the description. I will make sure I do better research in the future.

 

[benmychree]

You might like to pick up a copy of Brown & Sharpe's book "Practical Treatise on Milling and Milling Machines", there is a lot of info and tables, and many, many pictures, all of their machines, of course! I look for them on E Bay. Cincinnati also published a similar but larger and more technical book.

 

[Lo-Fi]

Great video on differential indexing here too, if you're interested;

 

[benmychree]

I will watch it! I am set up for differential indexing, and used it to make a master 127 tooth change gear to fit my ancient automatic gear cutter to cut a coarser change gear for metric threading on my 19" Regal LeBlond lathe, also made other change gears with prime numbers of teeth for threading diametral pitches.

 

[benmychree]

I note that in addition to the indexing computed above, also 5 turns and 15 holes on a 21 hole plate gives the same result with much fewer holes to count. A feature of a real B&S dividing head is that the sector arms have a graduation on them that coincides with a number in a column of their dividing tables, the setting for the above indexing with a 21 hole plate is 140, for the 49 hole plate, it is 139, you just set to the number, and no hole counting!

 

[BladesIIB]

I note that in addition to the indexing computed above, also 5 turns and 15 holes on a 21 hole plate gives the same result with much fewer holes to count. A feature of a real B&S dividing head is that the sector arms have a graduation on them that coincides with a number in a column of their dividing tables, the setting for the above indexing with a 21 hole plate is 140, for the 49 hole plate, it is 139, you just set to the number, and no hole counting!

I do show examples of different hole plates giving you the same result when I do the 6 index example. In my experience there is usually more than one way to get to the same result. Sounds like the B&S dividing head, and I am sure some other name brands have some great features. I was not able to find one of those that fit my budget and was trying to share a review on this model. Appreciate the feedback. I did update my Video thumbnails and descriptions as well as my posts in HM to correct my use of Indexing and call it Plain/Simple Indexing.