Model Engine Maker

Supporting => Tooling & Machines => Topic started by: RReid on June 08, 2021, 01:46:54 AM

Title: A small dividing head
Post by: RReid on June 08, 2021, 01:46:54 AM
Before starting the next engine project I decided to build a diving head that can be used on either my Taig mill or lathe. With a tip of the hat to a dividing head published by Tony Jeffree, I came up with my own design built around a Taig headstock spindle and a 30:1 worm gear. The frame is based on two pieces of 3” x 3” aluminum angle, which will be trimmed and screwed together to give the “box” dimensions I want. A riser block will raise it high enough for the 4 jaw chuck to clear the mill table, but with the block removed it will be on be on spindle center line when bolted to the lathe cross slide
(https://i.postimg.cc/kGXPBFfq/IMG-0753.jpg)

The hub of the gear wheel I have is 0.75" diameter, which doesn't leave much meat for a set-screw after boring to 0.67" for the spindle. So I made an “auxiliary hub” from some 0.875” hex brass. I turned a short .25” spigot on one end to center it in the gear bore for silver soldering, and a longer 0.375”  on the other side so it can be mounted in an ER-16 collet for boring and parting off.
(https://i.postimg.cc/0QCqkHGV/IMG-0750.jpg)
Title: Re: A small dividing head
Post by: kuhncw on June 08, 2021, 02:32:08 AM
Ronald,

That is an interesting design.  I'm looking forward to your build updates.

Chuck
Title: Re: A small dividing head
Post by: joe d on June 08, 2021, 02:35:50 AM
Ron:

I built one more or less to Jeffree's design, it's been very useful.  I suspect you will like yours once you've completed it.

Joe
Title: Re: A small dividing head
Post by: Thor on June 08, 2021, 05:00:48 AM
Hi Ronald,

 Your dividing head looks very nice. I too was inspired by Tony Jeffree to make my own dividing head using a MT 2 spindle from a Sieg X1 milling machine: http://files.thor-hansen.webnode.no/200000013-0eebe10dd7/Delehode2.pdf (http://files.thor-hansen.webnode.no/200000013-0eebe10dd7/Delehode2.pdf)

Thor
Title: Re: A small dividing head
Post by: RReid on June 08, 2021, 03:44:14 PM
Chuck, Joe, and Thor - Thanks for the input guys, much appreciated!

A note on the drawing might be in order. At the bottom of the page in the first picture you can see printed "Solidworks Eductional Product". I don't know if this is commonly known within this forum or not, but one of the nicest perks of a membership in the Experimental Aircraft Association (EAA) is a free annual license to that version of Solidworks. At only $40/year it's a bargain for 3D modeling software that is hardly reduced in functionality at all versus the big buck full version.
Title: Re: A small dividing head
Post by: RReid on June 09, 2021, 12:42:58 AM
Most of today's work involved easy but slightly boring brass boring. That included the gear wheel and two bushings to support the spindle in the frame. Didn't take any process pictures because, as usual, I forgot to. Pretty standard stuff anyway. Here's the end result.
(https://i.postimg.cc/nLnXgZML/IMG-0757.jpg)

That portion of the spindle to the right of the nut will be surplus, and I'll cut most of it off eventually. The only part still to make for the spindle is the brake.
Title: Re: A small dividing head
Post by: RReid on June 11, 2021, 01:11:44 AM
Switching focus now from the spindle to the frame. The frame consists of two pieces of nominal 1/4” x 3” aluminum angle. The “A” piece forms the base and the front (working) face. The upright leg was cut down to 2.5”, and both faces have to be machined for flat and square. Here I'm about to flycut that front face. These are very light cuts, so the blocking isn't really needed, but helps to dampen any vibration. Also visible is the 3/16” pilot hole that locates the future position of the spindle.
(https://i.postimg.cc/CxYmCKmN/IMG-0759.jpg)

And the result.
(https://i.postimg.cc/htrM2qYq/IMG-0760.jpg)

Next was to drill and tap 6 6-32 holes to fasten the “A” and “B” angles together. A selection of table clamps and C clamps keep everything together and in line. Three of the screws go up from the bottom, so those holes were also counterbored with an end mill to accept the heads of the SHCSs.

I usually start taps either in the drill press or the mill. In this case I did the drilling on the mill, so the tap goes into the chuck which is held by loosely tightened collet. The collet holds the chuck vertical and aligned, but is loose enough for it to slide up and down, making it easy to start a few threads worth by hand. Then over to the bench to finish the tapping, knowing the tap has been started straight.
(https://i.postimg.cc/QMdmPyLK/IMG-0763.jpg)
(https://i.postimg.cc/6QbcNfwj/IMG-0768.jpg)
(https://i.postimg.cc/PxL4fv5t/IMG-0769.jpg)

With the basic frame now assembled, it's time to think about boring it for the spindle. I plan to do this on the lathe, first with drills then a between centers boring bar. Here I've mounted the frame to the cross slide and am indicating it in.
(https://i.postimg.cc/G2yT3wz2/IMG-0771.jpg)

Then I lined up on that previously drilled pilot hole, and drilled through the back face.
(https://i.postimg.cc/htq3CsPV/IMG-0775.jpg)

Ultimately that bore needs to be 0.8” diameter. I'll go as far as I can with drills, up to 0.75” if all goes well. Then switch to a boring bar, which I will have to make. Hopefully out of this old piece of shafting.
(https://i.postimg.cc/6qx2yj1h/IMG-0772.jpg)
Title: Re: A small dividing head
Post by: Thor on June 11, 2021, 07:44:17 AM
Hi Ronald,

 You are making good progress. Using a between centres boring bar will make the holes for the spindle the same diameter and parallel to the lathe bed.

Thor
Title: Re: A small dividing head
Post by: RReid on June 12, 2021, 12:52:34 AM
I left off yesterday having drilled the start of the spindle bore to 3/16”. Today I continued drilling, going up in steps each time. Here is the last drill I used, 5/16”. It's roughly half as long as the lathe bed!
(https://i.postimg.cc/mk6jBzWx/IMG-0778.jpg)

I could have gone a little farther with drills, but I decided that since I now had clearance for that piece of old shaft I showed previously, I would switch from drilling to boring. But first I had to drill the bar for a cutter and a set-screw.  Turns out that key slot was really handy. It provided a nice indexing surface, making it easy to rotate the work 90 degrees for laying out and drilling those two holes. Here I'm laying out the center line of the first hole by measuring from the fixed jaw of the vise.
(https://i.postimg.cc/Vs7DjTr7/IMG-0780.jpg)

Then rotate and do the set-screw hole. I start taps on the drill press by turning the spindle by hand while applying downward pressure with the quill handles. Just a few turns, then back out carefully. A little dab'll do ya, then finish on the bench.
(https://i.postimg.cc/FHSpXHPq/IMG-0783.jpg)
(https://i.postimg.cc/c42hzncw/IMG-0785.jpg)

Here's the boring bar, mounted between centers (well, between 4J and center), cutter installed, ready for work. The cutter was ground from a broken center drill. Because of its geometry, the cutting edge is facing “down” and towards the headstock, so the boring proceeded by moving the carriage from left to right.
(https://i.postimg.cc/7LyVHrdL/IMG-0787.jpg)

Almost there.
(https://i.postimg.cc/G2LxDJcw/IMG-0788.jpg)

Success! Everything fits and the spindle turns nice and smooth. I'm pretty pleased with how that went. There's obviously no micrometer adjustment on that boring bar, so it would have been easier to have turned the bushings to fit the bore rather than the other way around, but it worked out by going slow and careful.
(https://i.postimg.cc/NMd7k9My/IMG-0791.jpg)
(https://i.postimg.cc/xdyPqFV3/IMG-0790.jpg)
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 12:31:41 AM
Well, it's not quite a dividing head yet, I still need to make a division plate and the attendant stop pin, etc. But with a simple utilitarian crank, it can now be used as a rotary table. At least I think so, I haven't had a chance yet to actually prove that. :thinking: At least the chuck goes round 'n' round when I turn the crank.
(https://i.postimg.cc/qMjPLmh8/IMG-0793.jpg)

(https://i.postimg.cc/Cx5W6jk9/IMG-0794.jpg)

(https://i.postimg.cc/SKzHmkZr/IMG-0798.jpg)

Since the Taig spindle I used has a “bearing pre-load nut” at the far end, which I retained but don't have any bearings to pre-load, I think I can use that nut as an effective brake, eliminating the need for a separate one. You can see it in this last picture.
(https://i.postimg.cc/5t75KC5K/IMG-0792.jpg)
Title: Re: A small dividing head
Post by: crueby on June 17, 2021, 12:38:48 AM
Can you use it in rotary table mode to make the division plate?


Do you need different plates for different numbers of gear teeth when cutting gears? I've never used a dividing head, don't know the ins and outs of them.
Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 01:07:35 AM
Can you use it in rotary table mode to make the division plate?


Do you need different plates for different numbers of gear teeth when cutting gears? I've never used a dividing head, don't know the ins and outs of them.

Yes....standard B&S dividing heads have 3 plates....they can be reproduced with what is there!....it's a lot of work, but it is doable.

RW Smith did a great write up on making indexing plates using a tape measure tape wrapped around a disk as a master...and made clock wheels with the result!....also remember, what ever error you have in the position of the holes in your plates, will be reduced by the gear ratio of the dividing head....so that helps alot.

Dave
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 01:19:38 AM
Quote
Can you use it in rotary table mode to make the division plate?
Yes. For example, since I used a 30:1 worm gear set, every full turn of the crank moves the work 1/30 of a revolution, and by drilling a hole at each turn of the crank, 30 full turns would produce a 30 hole division plate. Such a plate could then be used to make a gear (or any other segmented part) with 30 teeth or any other number of teeth that is a factor of 30 (2, 5, 6, etc.).

The other way division plates are sometime generated is by using a circular saw blade as a temporary indexing wheel.

Quote
Do you need different plates for different numbers of gear teeth when cutting gears? I've never used a dividing head, don't know the ins and outs of them.
It really depends on how many different gears you want to make. One plate typically has more than one hole circle in it, but multiple plates with multiple rows are usual for a comprehensive set. For my needs one plate with maybe three rows of circles (30, 36, & 50?) will probably be more than enough.

I've never used a dividing head either, I'm in learning mode too!
Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 01:38:14 AM
Ron....what is the gear ratio?     40 to 1 or something else?

Dave
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 01:56:50 AM
The gear ratio is 30:1.
Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 02:18:09 AM
I was going to throw some math out there, but as is usual, someones done it already

https://www.cgtk.co.uk/metalwork/calculators/dividing

Set this spreadsheet to " custom" and 30 for the gear ratio.  Then set out the plates you want to make or have.....

It will tell you what divisions are obtainable....

Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 02:21:51 AM
and here is an example of the math

https://www.bing.com/videos/search?q=dividing+head+formuala%27s&docid=608038928227046131&mid=95B19BB63B9B79AC12EB95B19BB63B9B79AC12EB&view=detail&FORM=VIRE

Dave
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 02:28:13 AM
Thanks Dave. I've bookmarked that calculator, it will be handy.
Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 02:37:38 AM
If you start with a 1 hole plate, then a 2, you can add hole counts using the dividing head...if you plan it out with that calculator, you can get nearly all divisions up to 50 with only a handful of holes....though prime numbers will need to be laid out I think..

Enjoy..

Dave
Title: Re: A small dividing head
Post by: steamer on June 17, 2021, 02:46:35 AM
For the prime  holes, you can calculate the BC, and the XY positions with this calculator....

http://theoreticalmachinist.com/BoltCircleCalc

Dave
Title: Re: A small dividing head
Post by: Thor on June 17, 2021, 07:14:50 AM
Hi Ron,

 If you have access to a 2D CAD program you can draw the (prime number) hole circles for the division plate(s) and print the drawing on paper and glue the paper to the division plate blank and then drill the holes. If you get it slightly wrong, use the first plate to generate a second one, then any erros will become much smaller.
 Here is a webpage that generate dials: https://www.cgtk.co.uk/metalwork/calculators/divider (https://www.cgtk.co.uk/metalwork/calculators/divider)
 It will at least give you one hole circle.

Thor
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 02:59:17 PM
Thanks Thor, Thanks Dave. Clearly there is more than one way to skin the division plate cat!

Going back to my earlier example of a 30 hole division circle, I said that it could be used to cut any number of teeth or segments that is a factor of 30. But in fact the possibilities go beyond that. It will also cut any number that divides into 30 with a Remainder that is a factor of 30.

As an example, imagine wanting to cut flats in bar stock to form the basis of crankcases for a series of radial engines of 5, 7, an 9 cylinders, with only a 30 hole division plate to work with.

The 5 cylinder case is easiest, 6 full turns of the crank for each flat (5 into 30 = 6).

For 7 cylinders, 7 goes into 30 4 times, with a remainder of 2. So each flat would take 4 full turns plus 2 additional holes.

9 cylinders is similar, 9 into 30 = 3 plus remainder 3. So 3 full turns plus 3 holes. Nifty huh?

An 11 cylinder radial wouldn't work though. 11 into 30 is 2 with remainder 8. Eight is not a factor of 30, so we would need a new hole circle. 24 holes would work, and that could be generated from the 30 hole circle. Also nifty.
Title: Re: A small dividing head
Post by: RReid on June 17, 2021, 11:15:09 PM
Using the partially completed dividing head, as discussed in the previous posts, I made a 30 hole division plate today. First off I lined up the spindle with the mill spindle and locked down the X and Y gibs.
(https://i.postimg.cc/R0HcVgRJ/IMG-0800.jpg)

I have a 3” diameter aluminum face plate that I had used in the past on my wood turning lathe. I chose to make that my “blank”. Conveniently, it has a 3/4-16 threaded hub, so I could screw it directly onto the spindle.
(https://i.postimg.cc/kgZQm0xd/IMG-0799.jpg)

That plate already has some holes drilled in it, four of which are at the same 0.8125” radius as I want my hole circle to be. So I lined up on one of the existing holes. Their diameter is too large though, so I then  turned and pressed in some ali rod to plug them. I marked the end of the crank with a fine Sharpie and taped on a piece of parting tool blade to serve as a pointer, to give me a reference for “one full turn”. Cheesy I know, but sometimes you just have to make do and get on with the job. :shrug:
(https://i.postimg.cc/cHGfKf99/IMG-0803.jpg)

Then it was just a matter of going around once with a center drill, then again with the final 1/8” drill.
(https://i.postimg.cc/Y0pgRMwQ/IMG-0805.jpg)

(https://i.postimg.cc/VvDtHpYp/IMG-0806.jpg)

(https://i.postimg.cc/fWKYLtxC/IMG-0808.jpg)

Still enough real estate left for up to 3 additional circles outside of this one. Later I'll remove the existing hub, since I expect to screw this plate directly to the side of the diving head. But the shop thermometer says it's 105 F out there, so I quit for today. I don't get paid enough to work when it's that hot.
Title: Re: A small dividing head
Post by: Kim on June 18, 2021, 05:25:40 AM
Great looking index plate, Ron!  And nice work on the dividing head/RT too.  Looks like a great tool!

Kim
Title: Re: A small dividing head
Post by: RReid on June 18, 2021, 02:45:54 PM
Thanks Kim! I hope you're finding time to at least think about your A3! :stir:
Title: Re: A small dividing head
Post by: steamer on June 19, 2021, 12:00:57 AM
ok....GOOD   you're thinking about it.........
Title: Re: A small dividing head
Post by: Kim on June 19, 2021, 05:27:17 AM
Thanks Kim! I hope you're finding time to at least think about your A3! :stir:
Yes, definitely thinking about it!  Just not getting a lot of time to actually work on it.  Should have some time this weekend?  (He says optimistically!)

What is that people say about having less time once you retire?  :-\
Kim
Title: Re: A small dividing head
Post by: simplyloco on June 19, 2021, 05:45:37 PM

What is that people say about having less time once you retire?  :-\
Kim

I've been retired now for 15 years and I don't know how I EVER found time for work!
Title: Re: A small dividing head
Post by: RReid on June 19, 2021, 08:45:07 PM
Quote
What is that people say about having less time once you retire?
Quote
I've been retired now for 15 years and I don't know how I EVER found time for work!

I agree, but I still say it's the best job I ever had!
Title: Re: A small dividing head
Post by: RReid on June 22, 2021, 01:14:44 AM
A relative asked me to make a pair of door mirror clamps for his vintage pick-up truck, to replace an original (in front in the first pic) that is cracked and stripped. He also wanted them slightly larger and stronger. They are offset turned, bored, then the larger diameter was partially milled away. That has diverted me off of the DH project for a few days, but I want to try to finish them off using the DH as a rotary table.
(https://i.postimg.cc/KzcZhtBD/IMG-0815.jpg)
(https://i.postimg.cc/63HBWThJ/IMG-0825.jpg)

To do that, I'll need the DH mounted to the mill table, along with both the 4J chuck and the lathe tailstock. And to do that, I need a riser block that's a bit over 1” thick. The half disc of aluminum that I have the lathe mounted to has enough thickness, and I can spare part of it, so that's what I'm using. I cut a chunk off on the bandsaw, then squared it all up on the mill with a flycutter. Mounting holes have been drilled, so all that's left is to flycut it down to the exact thickness needed for the spindle center and the tailstock center to line up.
(https://i.postimg.cc/ZKFQkXYp/IMG-0823.jpg)

What's wrong with this picture? No, I don't try to flycut loose parts, it's an “after thought" photo. :Doh:
(https://i.postimg.cc/XYjznxXh/IMG-0824.jpg)
Title: Re: A small dividing head
Post by: steamer on June 22, 2021, 01:19:22 AM
You"re going to be a very very busy man!

Coming along nicely...
Title: Re: A small dividing head
Post by: RReid on June 24, 2021, 01:17:06 AM
Thanks Steamer! Busy is OK, helps ward off brain stagnation.

Using the DH in rotary table mode worked out pretty well to finish off those old truck mirror clamps.
(https://i.postimg.cc/DyRQtwvy/IMG-0829b.jpg)

With that out of the way I've gotten back to finishing the rest of the components needed to use it in the intended dividing head mode. That starts with getting the division plate I made earlier mounted. I turned off most off the boss for the existing 3/4-16 mounting hub, and bored it to 3/4” ID, removing the threads in the process. I then tapped in a brass plug. It's a nasty old thing, with an offset hole through it.  Doesn't matter though, it's only temporary and I could work around the hole.
(https://i.postimg.cc/7YrYdvvr/IMG-0834.jpg)

I center drilled it, the took to whole shebang, still in the chuck, over to the mill to drill a ¼ hole using an end mill. Since the hole I want and the hole already there overlapped a bit, a drill bit wouldn't have run true, but an end mill will. I can now slip the division plate over the worm shaft where the crank arm also attaches. With the worm shaft and the division plate concentric, I tap drilled through the plate and into the side plate of the frame for 3 6-32 screws. Then the holes in the frame get tapped and the plate gets clearance drilled. Got two of the three done today, one left for tomorrow.
(https://i.postimg.cc/CxFMMjLv/IMG-0836.jpg)

Last step will be to knock the brass plug out. Then move on to making a nicer crank arm with a sprung stop pin, etc.
Title: Re: A small dividing head
Post by: RReid on June 25, 2021, 10:24:21 PM
To finish off the DH, I made a brass stop pin and set it up with a spring cut down from a ball point pen for engagement, and a 5-40 threaded shank with finger nut so I can retract and lock it for “cranking”. Since I've only made the one hole circle at this point, I didn't worry about making the pin adjustable for radius. Ditto for making a pair of sector arms, those these can be pretty easily added as the need or desire arises.
(https://i.postimg.cc/jdx0D5Rx/IMG-0842.jpg)
(https://i.postimg.cc/8PZ8MSCh/IMG-0843.jpg)

So at this point I consider this small dividing head to be “finished”. Here are few pictures of some of the set-up options it offers.

Horizontal, with 4J chuck. The chuck jaws are reversed and set for a 3” diameter, and there is still plenty of clearance over the table.
(https://i.postimg.cc/6pqkhm7F/IMG-0845.jpg)

Horizontal, between centers with standard Taig tailstock. The dovetail plate is the same one Taig uses to mount the headstock on the milling machines.
(https://i.postimg.cc/J7KYdQW8/IMG-0847.jpg)

Vertical, using the lathe's milling attachment.
(https://i.postimg.cc/vHB2R6QV/IMG-0848.jpg)

Vertical, using a bit of extruded aluminum angle.
(https://i.postimg.cc/rFPnqFmY/IMG-0849.jpg)

Mounted to the lathe cross slide.
(https://i.postimg.cc/rwRhsXRy/IMG-0851.jpg)

Overall I have to say I'm pleased with the compactness and versatility of this design. It remains to be seen what shortcomings show up as I get to using it more!
Title: Re: A small dividing head
Post by: Kim on June 25, 2021, 10:27:47 PM
That is really nice, Ron!

And you've got a lot of good 'use modes' covered with that design.

Well done!
Kim
Title: Re: A small dividing head
Post by: crueby on June 25, 2021, 10:51:17 PM
Sector arms? What are they/what do they do?
 :popcorn:
Title: Re: A small dividing head
Post by: steamer on June 26, 2021, 12:38:59 AM
Yes   Make ye some sector arms!....Saves a lot of counting and head scratching in use.

Dave
Title: Re: A small dividing head
Post by: steamer on June 26, 2021, 12:42:50 AM
This is part two of his lecture on dividing heads...but he gets into the sector arms explaination, and how to use them   


Look at part 1 too...

https://www.youtube.com/watch?v=kFjSHtyhOmg

Dave
Title: Re: A small dividing head
Post by: steamer on June 26, 2021, 12:45:59 AM
Also ...consider a spindle lock.    With a spindle lock, you avoid the work vibrating due to the back lash of the gearing...it makes for a very rigid setup, and better accuracy.

Dave
Title: Re: A small dividing head
Post by: RReid on June 26, 2021, 01:01:08 AM
Quote
Sector arms? What are they/what do they do?

Sector arms are an aid to keeping track of the " turns plus holes" on the division wheel. They consist of two arms that can rotate independently on the worm crank axis, be locked to rotate as a pair, or be locked in place.

In use, one arm would be set at the "starting hole", which is also the hole you must return to to get one full revolution of the crank. The other arm is set at whatever number of holes beyond the starting hole is required for the job in play, let's say as an example 5 holes beyond. They are then locked together as a pair, so they can later be rotated together without loosing their angular separation.

The first cut is made with the pin in the starting hole, then the crank is rotated the required number of full turns (marked by the 1st arm, plus the 5 holes (marked by the 2nd arm), the pin is inserted there, and the second cut is made. Next, the arms are rotated together to bring the 1st arm to the current pin position, and the cutting process is repeated.

This image of a Brown & Sharp version should help.

(https://i.postimg.cc/503DcngM/Sector-Arms-B-S.jpg)
Title: Re: A small dividing head
Post by: crueby on June 26, 2021, 01:03:24 AM
Thanks for the explanations guys! Great videos too!
Title: Re: A small dividing head
Post by: steamer on June 26, 2021, 01:04:28 AM
Quote
Sector arms? What are they/what do they do?

Sector arms are an aid to keeping track of the " turns plus holes" on the division wheel. They consist of two arms that can rotate independently on the worm crank axis, be locked to rotate as a pair, or be locked in place.

In use, one arm would be set at the "starting hole", which is also the hole you must return to to get one full revolution of the crank. The other arm is set at whatever number of holes beyond the starting hole is required for the job in play, let's say as an example 5 holes beyond. They are then locked together as a pair, so they can later be rotated together without loosing their angular separation.

The first cut is made with the pin in the starting hole, then the crank is rotated the required number of full turns (marked by the 1st arm, plus the 5 holes (marked by the 2nd arm), the pin is inserted there, and the second cut is made. Next, the arms are rotated together to bring the 1st arm to the current pin position, and the cutting process is repeated.

This image of a Brown & Sharp version should help.

(https://i.postimg.cc/503DcngM/Sector-Arms-B-S.jpg)

 :ThumbsUp: 8)
Title: Re: A small dividing head
Post by: RReid on June 26, 2021, 01:19:02 AM
Quote
Also ...consider a spindle lock.
Quote
Thanks for the input and the videos, Dave!

I do have a spindle lock, consisting of a nut at the back end of the spindle that can be tightened against the bushing. That is effective, but I can see where it may prove awkward if it requires two wrenches and two hands to tighten it without rotating the spindle. If that's the case I'll install a more traditional clamp style brake. That was the original intention anyway, so there is room for it.
Title: Re: A small dividing head
Post by: steamer on June 26, 2021, 01:21:47 AM
Quote
Also ...consider a spindle lock.
Quote
Thanks for the input and the videos, Dave!

I do have a spindle lock, consisting of a nut at the back end of the spindle that can be tightened against the bushing. That is effective, but I can see where it may prove awkward if it requires two wrenches and two hands to tighten it without rotating the spindle. If that's the case I'll install a more traditional clamp style brake. That was the original intention anyway, so there is room for it.

 :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: A small dividing head
Post by: RReid on August 27, 2021, 01:08:58 AM
One of the motivations for building this dividing head was a desire to learn to cut my own gears for future projects. Since my next engine project will likely be the Upshure Farm Engine, the future is now. That engine requires two 48 pitch gears, one with 30 teeth, the other with 60.

I've looked at the cost of involute gear cutters, read up on the Stevenson Button Method of making the same, methods for making hob-like cutters, etc. But as a trial attempt at gear cutting, I decided to go with my usual KISS approach, and see how well non-involute gears would work. To that end I reground a 60 degree threading tool to 40 degrees, making a simple, straight sided 20 deg Pressure Angle, single point cutter. I also made a flycutter style holder for it.

Armed with those, I turned up a pair of brass blanks to make the 30 tooth gear, and set it up on the mill, along with the dividing head and the tailstock for support, and starting wailing away.
.(https://i.postimg.cc/GhYKGW7x/IMG-1191.jpg)

(https://i.postimg.cc/PNGLdF1t/IMG-1189.jpg)

I made two gears so, partly for practice, partly so I could see how well they mesh. They don't look as refined as good commercial gears, but they do seem to mesh fine and work smoothly enough at “finger rotation speed” on the sophisticated test fixture.
(https://i.postimg.cc/y62nJ1PN/IMG-1194.jpg)

(https://i.postimg.cc/9XDJFRyS/IMG-1196.jpg)

Those are the first gears I've ever made. After cleaning up, I came in and treated myself to a beer.
Title: Re: A small dividing head
Post by: crueby on August 27, 2021, 01:47:27 AM
First set of gears came out great, and no pile of rejects in the bin - definitely worth the celebration!

For slow moving gears, the simple shape used in early clocks is not too hard to grind cutters for. Did that style on a wall clock 15 years ago, its still keeping great time.

Pretty soon you'll be cutting bevel gears, then helicals (I have not tried those yet myself! )

 :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: A small dividing head
Post by: Kim on August 27, 2021, 05:40:56 AM
Nice gears, Ron!
I used the button method to create cutting tools for some gears I made.  I didn't find that method too hard and I liked the gears I came up with.  If you like these, go for it!

Making gears is pretty exciting!
Kim
Title: Re: A small dividing head
Post by: RReid on August 27, 2021, 05:27:55 PM
Thanks Chris! Thanks Kim!
I agree that the button method would be the next logical step. It would be interesting to compare both sets of gears in the same application. For something like the Upshur I suspect the difference may be hard to detect. Vixen's W165 engine? ;)

Anyway, I'm heading into another hiatus while we have a different set of grandkids here for the coming week, then take them home and spend a few days there with the parents and the toddler.
Title: Re: A small dividing head
Post by: Kim on August 27, 2021, 06:32:30 PM
Enjoy the grandkids and your family!  :D

Kim
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