• We want to encourage those of you who ENJOY our site and find it USEFUL to DONATE and UPGRADE your membership from active member to donating or premium membership. If you want to know the differences in membership benefits, please visit THIS PAGE:

    https://www.hobby-machinist.com/premium/

    Donating memberships start at just $10 per year. These memberships are in fact donations that help pay our costs, and keep our site running!
    Thank you for your donation, God Bless You

  • As some of you know, I have wanted to stop managing H-M for some time. It's a tremendous strain on my personal life. I want to set up my own shop. In September, September 15, to be exact, it will be 8 years that Hobby-Machinist has been in existence.

    I have been training VTCNC to run things here. Dabbler is going to learn too. I feel that they are ready to start taking over the operation. I will be here to help in case they need, but I don't think they will. Tony Wells is and will be here also to consult with. I will be doing backups, upgrades, and installing addons. Other than that, I will not be around. I am leaving this place in good operating condition, and financial condition.
    --Nelson
[4]

A Dividing Head Anyone Can Build

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

rustwa

Swarf
Registered
Joined
Jul 14, 2014
Messages
7
Likes
0
#31
Mark,
This is an inspirational project. I like seeing that little lathe work. I find a new way to use my 9a with every project. Thanks
 

iron man

Active User
Registered
Joined
Feb 7, 2013
Messages
788
Likes
59
#32
Nice work.. Ray
 
Last edited:

Thoro

Active User
Registered
Joined
Jan 1, 2014
Messages
174
Likes
5
#33
Add me to the group of people fascinated. I will definitely be following this closely. Thanks for the documentation!
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#34
I have written a computer program that solves indexing problems and if desired will print out a chart of solutions for the workshop. Rather than going into long details here check out the web page.

http://www.dogcreek.ca/shopcalc/shopcalc13/index.html

This is my latest version and not yet publicly released (still waiting for Spanish and Dutch translations). This is free software.

I recently downloaded the latest version of shop calc. It was talked about on another forum I was reading. I haven't really looked at it yet, but will go do that now. ........ Rats!..... I went to check it out but it works with a few ratios but not the 30:1 for the dividing head. Oh well, that is my luck.

Thanks,
Mark
 

lnr729

Active User
Registered
Joined
Jun 20, 2012
Messages
43
Likes
6
#35
I recently downloaded the latest version of shop calc. It was talked about on another forum I was reading. I haven't really looked at it yet, but will go do that now. ........ Rats!..... I went to check it out but it works with a few ratios but not the 30:1 for the dividing head. Oh well, that is my luck.

Thanks,
Mark
Shopcalc can be customized for 30-1 quite easily. In the same folder as ShopCalc there is "DoNotEditOrDelete.ini" that can be opened in notepad. Scroll down to the very bottom and type in "[30-1]" then press Enter and on the new line type "0=30-1" then press Enter again (it is very important that you press enter after "0=30-1") or you will get an error message.

Now when you start ShopCalc you can select 30-1 and start adding the hole plates that you will use. Obviously I need to provide a method to add a custom ratio. That will take a while as "She who must be obeyed" has me remodeling the bathroom.
 
Last edited:

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#36
Shopcalc can be customized for 30-1 quite easily. In the same folder as ShopCalc there is "DoNotEditOrDelete.ini" that can be opened in notepad. Scroll down to the very bottom and type in "[30-1]" then press Enter and on the new line type "0=30-1" then press Enter again (it is very important that you press enter after "0=30-1") or you will get an error message.

Now when you start ShopCalc you can select 30-1 and start adding the hole plates that you will use. Obviously I need to provide a method to add a custom ratio. That will take a while as "She who must be obeyed" has me remodeling the bathroom.
COOL!! ... thank you very much..... now I can figure my plates much easier.

THANK YOU!
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#37
Almost done with the spindle.
51 spindle.jpg This is the spindle. The only thing left to do is thread the rear end.

50 spindle.jpg The center of the spindle is bored to accept 3C collets and the outside is threaded 1 1/2-8 to acept a chuck or a face plate or an ER 40 adapter.

52 spindle.jpg This is the rear of the spindle bored to .750 halfway through to accept the 3C collet draw bar. this was not planned but is not a problem. the rear end wall is .063" thick. Plenty of room for the 7/8"-28 threads on the outside, but no room for a key for the gear, so I will be using two grub set screws 90 degrees apart with a slight dimple in the spindle to capture them. All the load is on the front half of the spindle ( 1.250" diameter), so the thinner rear wall is not a problem since it is only support and not really load bearing. There is very little stress in this area. The reason it worked out this way was I wanted to use the gear as it was and not modify it or half to make a new key way. That backfired because now I can't use a key anyway. Ideally, I could have bored the gear out to 1" and had a thicker wall. But it doesn't matter, this is just as good and I am trying to keep things easy and simple so anyone can build this and end up with a good quality tool. Tomorrow .... thread the rear of the spindle and make lock nuts ..... I hope.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#38
This morning I threaded the rear of the spindle 7/8"-28 and made two lock nuts to put on the rear of the spindle.
14 completed spindle.jpg This is the completed spindle. ready to go.

13 facing lock nuts.jpg After making the lock nuts, I threaded them on the spindle and face both sides of the lock nuts while on the spindle so they would be perfectly square.

15 alining body to mill.jpg I needed to face a bearing pad on the rear of the body but it had to be square with the spindle bore. To line this up , I put a bushing and a rod in the bore and the other end of the rod in the collet in the mill spindle. this held everything in alignment while I clamped it down for milling.

16 milling rear brearing pad.jpg After clamping down the rear bearing pad is milled on the body. this makes a flat surface for the lock nuts ( or bearings, if I use them) to ride against holding the spindle in the body.

17 mock up of parts.jpg With all that done, it is time to make the other end of the body. A piece of 3 1/8" diameter steel bar stock is turned to size and a trunion bearing surface is turned just like the other body end. Next a slot will be cut for the clearance for the gear.
18 lathe table adapted to Burke.jpg In order to hold this piece on the mill, I adapted my lathe milling table by drilling two 3/8" holes so it can be bolted on the mill table. This worked so well, I think I will make a auxiliary table just for the mill ).
19 milling end of body.jpg The body end is clamped down and using a .375" wide cutter it was short work to mill the slot. It was almost 3 cutter widths wide and I was taking .200" cuts.

20 test fit end of body.jpg Here is the test fit of the body parts. You probably get the idea of how this works now, but if you don't ,, keep watching .....more tomorrow. I need to drill and bolt these parts together, need oilers installed to oil the bearings, and get started on the base unit.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#39
today , I finished the body and started the base.

1drilling alignment.jpg I used a hose clamp to hold the body parts aligned while I drilled for bolts and pins to hold it together.

2bolts and pins.jpg After drilling, tapping , and reaming, the body is finished with two 1/4-20 bolts and two .750"alignment pins.

3fitting trunion.jpg The base will start with a piece of 4" x 6" x 1/2" thick angle iron. I bored a 2.750" hole for the body trunion to fit. I also fly cut the back square with the bottom and will fly cut the bottom flat.

4fitting trunion2.jpg Another view of how the body and base will go together. I am making end caps for the trunions that will clamp with two bolts. when loosened the spindle can be rotated to the vertical position or anywhere in between.
 

Baithog

Florida Machinist Group Moderator
Registered
Joined
Feb 7, 2014
Messages
349
Likes
143
#40
I realize that you are way down the rabbit hole now, but - If the body was larger in diameter, then you could rotate the the head on the worm axis, rather than the spindle axis. That way the plates, sectors, handle, and all would stay in the same place when the head was rotated from horizontal to vertical.

Larry
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#41
You are correct , but there are several things to consider. First , I am using material that is on hand when possible. Second, I looked at doing that,but it made the whole unit too large. I need to keep it small to fit on smaller mills, like my Burke where the table is only 16 inches long. I didn't want this to be a big monster,like so many of these are. Also, I am trying to keep it as easy as possible to make so that almost any hobbyist can make it. I did make it bigger to handle a six inch swing. Originally , it was to be a four inch swing . This made it higher ( which I don't really like because the Burke mill doesn't have a lot of height ).Rotating on the worm axis would have made it way too high I think. I also considered the fact that the plates and such will move, but it is only 90 degrees and I don't think it will matter much because it is a small change in position.

I am glad to see some of you thinking on the design here and it can easily be altered for those with a larger machine like a Bridgeport.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#42
I roughed out the base on the band saw today and drilled and tapped the body for two mounting bolts.

1body mounted to base plate.jpg I will round the top of the base , but wanted to test fit everything before I do. The two 3/8 bolts clamp the body and clamp plate against the base to hold its position. I designed this sort of like the Ellis dividing head, but there will be a second base arm and clamp plate on the other side ( where the Ellis only had the one). I think it is sturdy enough but I just feel better with both sides clamped. Then there will be no vibration from the body hanging on only one end.
2veiw of trunion clamp plate.jpg the end view.

2veiw of trunion clamp plate.jpg
3test fitting a 6inch back plate.jpg I test fit a 6 inch back plate to make sure of clearance for a chuck. There is enough clearance to put my 7 1/4" face plate on. Now I will take it apart and finish milling the base. Then start the other trunion plate. I am still working on t he design for the worm to mount.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#44
I got more done on the base today.
1base finished.jpg I rounded the frame and fly cut the back flat. This is now my reference surface.
2base finished.jpg The bottom is cut perpendicular to the back and the front is finished where the body clamps.
3 base finished.jpg

test fit on mill.jpg The unit is test fit on t he mill to check for size. Everything looks pretty good so far.
drilled oil holes.jpg While it was apart, I drilled two oil holes to lube the spindle bearings.
graduations.jpg I also put the graduations on the body. This is the first time I did a set and no mistakes . It came out perfect.
gussets in frame.jpg I made these gussets for the frame and was going to weld them in, but not sure yet. I was thinking if I did this the frame would be plenty sturdy with out a second trunnion. This would make the worm set up easier. Then I figured out another setup for the worm that will still allow the second trunnion, So I am a little undecided here. ( this happens when you build by the seat of your pants). I am still leaning towards putting the second trunnion on. I know there will be no vibration that way. ( I actually think it would be fine with the gussets also). I have four 1/4 inch plates to make hole plates with and a 1" thick plate to turn a chuck back plate. all are 5" in diameter. I am also working on parts to mount the worm. I want to be able to disengage it for simple indexing. I also have to make a draw bar for the 3C collets.
 

tomh

Registered
Registered
Joined
Jan 14, 2013
Messages
290
Likes
158
#45
Mark
Looking good to me. Follow your gut and Go with the second trunnion.
you know the old saying nothing to strong ever broke.:encourage:

Tomh
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#46
I started working on mounting the worm for the gear set. I started by making a plate 7/8" thick and boring a hole to fit the end of the body. It is also counter bored to register on both diameters on the end of the body.
1worm mounting plate.jpg

2eccentric bushing.jpg I made an eccentric brass bushing to mount the worm shaft in. It is .063" eccentric and will allow the fit of the gears to have no back lash. I also turned a steel shaft for the worm to mount on.

worm mock up1.jpg This is the set up all mocked up.The shaft turns easy and free. I was going to make a setup to disengage the worm to do simple indexing. I started thinking about an eccentric to dis engage and the switched to a two piece shaft to slide the worm and disengage it. Both of these were getting complicated ,but doable, when I realized none of this is needed. the gears are not enclosed so all I have to do is remove the one nut that will be on the rear end of the shaft ( it holds the worm on) and slide the worm off to do simple indexing. To go back to dividing, just slide the worm back on and replace the nut.
worm mock up2.jpg This is the end view of the mock up. The next time yo see this plate, it will be cut down, shaped and polished. It rotates nicely with the body and the change in position for the index shaft is minor. that is why I didn't complicate things by rotating on the worm axis. The idea is to keep it simple but make a quality piece of tooling. So far , I am impressed with the project.

The plates I have for the index plates will get machined. I kind of wanted to have them surface ground before drilling them, but all the local machine shops are gone in this area. I know of one place that may be able to do them ( you out there Mike?). I will check on that tomorrow. The other option is to face them on the lathe maybe.
 

ogberi

Active User
Registered
Joined
Oct 20, 2014
Messages
494
Likes
410
#47
Beautiful work, Mark!

The graduations came out looking fantastic.

I'm a tiny bit confused -

If I'm imagining it right, the second trunnion goes to the inside of the plate that secures the worm gear shaft, correct? I can see the layout lines on the worm gear shaft plate, and it would have to be affixed to the body of the indexer, correct?

How much space is there between the bottom of the worm gear shaft eccentric and the top of the indexer body? Looks close in the pictures, but that can be deceiving.

I really like this project. Is it going to get the black wrinkle finish same as the tool grinder?

Can't wait for the next installment!
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#48
Beautiful work, Mark!

The graduations came out looking fantastic.

I'm a tiny bit confused -

If I'm imagining it right, the second trunnion goes to the inside of the plate that secures the worm gear shaft, correct? I can see the layout lines on the worm gear shaft plate, and it would have to be affixed to the body of the indexer, correct?

How much space is there between the bottom of the worm gear shaft eccentric and the top of the indexer body? Looks close in the pictures, but that can be deceiving.

I really like this project. Is it going to get the black wrinkle finish same as the tool grinder?

Can't wait for the next installment!
I think I will answer your question in the next post. It is confusing because that photo you saw the plate is not all the way on the body.

Thank you for mentioning the finish. I have been contemplating what to do. I like the black wrinkle finish and it is durable. I was also considering hammer tone paint, but it is not as durable. Any suggestions?
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#49
Was a hard day in the shop, but an enjoyable one. The first thing I did was cut the excess off the worm mounting plate.
end view of plate.jpg If you notice , the worm hole (hee-hee) was bored out form .750" to 1.063". In this photo , the plate is all the way on the body. This was confusing in the previous photo yesterday. The trunnion sticks through .150". when the trunnion is clamped the worm plate will be sandwiched between the body and trunnion . The reason for making the hole larger is a major revision. My plan for disengaging the worm failed miserably and I had no back up plan. After 4 hours of thinking and machining blindly, I came up with a new plan, Thus the bigger hole.

Notice the plate has been trimmed and rounded, and sanded smooth. This plate will attach to the body with two set screws. The trunnion also captures the plate. it is a very sturdy setup. When the body is rotated, the plate rotates with it. There is a flat on the left side of the plate. I have plans for that. the flat on the top is there in case I need it later. If not the top will get rounded also.

worm  mounted.jpg Here the worm is mounted with the eccentric. There is another piece that goes on the shaft to hold the index plates and sector arms. I had started it as one piece but because it was 3.375" long, it was hard to bore the .500" shaft hole the length, so I made it in two pieces and ill lock-tite them together.

worm engaged.jpg In this photo , the worm is engaged. By turning the eccentric bushing 90 degrees, the worm disengages as in the next photo.
worm disengaged.jpg Here the bushing has been rotated 90 degrees and the spindle free turns for direct indexing. There will be a small lever to accomplish this. I think I will also spring to have the local engraving shop make me a couple plates. the first one will say "WORM" and have "IN at one end and "OUT at the other. I will put it on the flat on the top of the plate or on the top curve if I round it. I will also have a few tiny plates engraved that say "OIL" to install by the oil holes. I have oilers with a lift up cap I was thinking of using or look for some ball oilers. they would be nicer. I need to cut the end off the worm shaft and thread it for a nut. another option I am considering is a groove and "e" clip to hold the worm on the shaft.

So far there is about $30 in this project. I have built it from scraps mooched from scrap bins at a local industry and my own scrap box. The gears were supplied by my friend Nelson Collar and I designed around the gears. I wanted to keep it cheap, but I am so impressed with the way it is turning out I am going to spring for about $30 worth of brass to make the sector arms and index handles from brass. And another $30 for engraved plates. It will make it look real nice.
 

mattthemuppet2

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Sep 28, 2013
Messages
1,609
Likes
878
#50
I never cease to be impressed by your work Mark! Whatever mistakes you make your projects always end up looking like professionally made pieces :)
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#51
I never cease to be impressed by your work Mark! Whatever mistakes you make your projects always end up looking like professionally made pieces :)
I make mistakes, sometimes big and sometimes small. When I put the graduations on ,I put them on and realized they were on the bottom, so I did a second set on the top. No one will ever see them unless they look at the under side.
 

ogberi

Active User
Registered
Joined
Oct 20, 2014
Messages
494
Likes
410
#52
I think the black wrinkle finish will look good on there. It'll match the tool grinder too. Do you plan to put a sheet metal guard over the worm & gear to keep swarf from getting tossed into them by the cutter?
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#53
And the winner is ..... BLACK WRINKLE FINISH. I painted the first part today and chose the black wrinkle finish because it looks expensive and is durable.

I spent a lot of time figuring out the worm setup to get everything I wanted. This photo is the complete worm assembly. I had to make the eccentric and the hub to hold the index plates in two pieces and lock-tite them together . I cut the flats on the end of the shaft to hold the index handle and made a pretty brass hand wheel to hold the index handle on. I wanted it easy to remove to change plates. I also threaded the shaft and put a lock nut to hold the worm on.
worm assembly.jpg

dividing head assembled.jpg This is the assembly of what is done so far. The worm mounting plate is painted and mounted. I should not have to disassemble it from the body anymore. There is a set screw in the back side to lock it to the body. It is also a kind of press fit on, so it will not move. it rotates with the body to go to the vertical position. You can also see the fancy brass hand wheel to hold the index handle on. There is a set screw assembly made up of a brass plug and two lock set screws in the front of the plate in the photo. This brass plug provides a little tension on the worm eccentric so it doesn't flop back and forth. It requires a light push to rotate the worm to engage or disengage and it will stay in position until it can be locked. The little 3/16" diameter brass lever sticking up is to engage or disengage the worm by rotating eccentric using this lever. I ordered a nice red knob for it from McMaster Carr. The gears turn very smoothly with almost no detectable back lash ( which is adjustable by the eccentric to be as loose or tight as I want.

worm engagement lock.jpg This is a rear view. The "T" handle is the lock to secure the worm eccentric in position. You can see the trunnion sticking through the plate .150". Originally there was not going to be an outboard trunnion and I still believe it is sturdy enough without it, but I am putting one on. It will be a lighter weight assembly made from 1/4" steel plate. By having it , there will be the little extra support and make things that much sturdier and prevent vibration of the body hanging out there.
second trunnion.jpg This plate is the outboard trunnion support. It is 1/4" steel plate. due to the close area of the worm mounting, the trunnion ring is not as heavy as the main support on the other end. You can see a narrowed section for 90 degrees that had to be relieved to allow the rotation to the vertical position. This assembly is heavier than it looks. When the ring is captured between the body and end plate, there is a total thickness of 1/2" of steel clamped up. It will provide more than adequate support on this end.

second trunnion test fit.jpg Here the trunnion is mounted. I still have to put the 3/8"-16 bolts in that clamp everything together. There will also be a heavy duty bracket to connect the second trunnion plate to the main base. I still have to drill and tap three 10-24 holes in the plate hub to mount the index plates. This will be done when the plates are made and all drilled at the same time.

In answer to the question asked about a cover for the worm gear to keep swarf out. YES, there will be a cover over the gear. I just haven't designed it yet and it will be one of the last details done. There will be a direct index plate behind the chuck with 24 and 36 holes in it and also marked in degrees. There will be a spring loaded pin to engage this plate when it is in use. I left that flat on the front side of the worm plate to fasten the spindle lock to. Yes, I will need a spindle lock . I also need to make a center and drive dog for working between centers. I have the material for it on hand.

I have tried to put everything in this project that the big honking 200 pound heads have. :

1.) a thirty to one gear ratio which will cover all divisions up to 50 and many others above using a minimum number of holes circles.
2.) 1 1/2"-8 threaded spindle that also accepts 3C collets and utilizes all my lathe chucks and face plates, giving me maximum versatility.
3.) the ability to rotate 90 degrees to the vertical position as well as the horizontal position.
4.) an easy to use eccentric to disengage the worm and allow simple indexing using a plate and spring loaded pin.
5.) A spindle lock to lock the spindle in position.
6.) easy to remove index handle ( no tools needed) and sector arms which will make plate changes simple.
7.) The unit is relatively small but heavy duty and fits nicely on the smaller mills such as the Burke. One person can carry it!

Have I forgotten anything?
 
Last edited:

ogberi

Active User
Registered
Joined
Oct 20, 2014
Messages
494
Likes
410
#54
I can think of only one thing that could make it a little bit better of a tool, and it's a minor thing.

A spring loaded pin in the trunnion that engages holes in the body at commonly used angles, or at least horizontal and vertical. That would make setup or switching a breeze, and intermediate angles could be added to cut things such as bevel gears.

I wouldn't call it a necessary feature, and I'm not even sure if the big dollar heads have that. But it would be handy to just pull the plunger, and rotate the body until the plunger drops in, knowing you'll be perfectly horizontal or vertical. And it's one more item on that that can be shiny. ;)
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#55
I can think of only one thing that could make it a little bit better of a tool, and it's a minor thing.

A spring loaded pin in the trunnion that engages holes in the body at commonly used angles, or at least horizontal and vertical. That would make setup or switching a breeze, and intermediate angles could be added to cut things such as bevel gears.

I wouldn't call it a necessary feature, and I'm not even sure if the big dollar heads have that. But it would be handy to just pull the plunger, and rotate the body until the plunger drops in, knowing you'll be perfectly horizontal or vertical. And it's one more item on that that can be shiny. ;)

Ahhhh .... you know I like shiny things.

I had actually thought about that very feature, but didn't do it because I didn't think it would give great precision and I could read the degree scale as good. BUT... after moving the built assembly a few times, I realize this could be a handy item, so I may just go ahead an add it soon.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#56
I am really pleased with the way this project is turning out.

I noticed when assembled the shaft flops back and forth like the button on the outhouse door without the handle and knob installed, so I decided to install an e-clip to keep everything in place.
1groove for e-clip.jpg I ground a .046" wide grooving tool to cut the groove for the e-clip. 2e-clip test fit.jpg the groove is cut .052" deep per the chart online from the manufacturer and the clip fit perfect.

3e-clip installed.jpg This is the clip installed. It is ALMOST perfect. There is .008" endplay in the shaft. It reall won't matter but I want to cut a brass shim at .007" to remove that slack.

Next I made up a draw bar for the 3C collets.
4draw bar for 3C collets.jpg The draw bar has a brass end that has a hand wheel to tighten it with. I will cut wrench flats on the brass stub but have not done that yet. Most of the time, I only hand tighten collets.
5base frame cut for bracket.jpg I machined the end of the base flat and square to accept a bolt on extension made from 1" thick steel plate. A step .475" x .500" is cut in the 1 inch plate and it is bolted through and into the end of the base to attach it.

6frame after painting2.jpg With the extension attached the frame is painted with Black wrinkle finish and it came out really nice.
7frame after painting.jpg Another view of the painted frame. Now to assemble the head for the last time.

8front view.jpg This is a front view of the dividing head assembled. the whole assembly works great. very smooth. i put a collet in the spindle, which reminds me, I need to make a thread protector for the spindle. ( details just keep popping up).

9rear view.jpg This is a rear view of the dividing head. you can see the draw bar knob that holds the collets in ( I will cut the wrench flats tomorrow). To the left is the set screw locking the worm mounting plate to the body. It was a press fit on , but this will insure it never moves out of place. There is an oil hole to lube the rear spindle bearing above the draw bar in the photo. the "T" handle locks the worm position for engaged or disengaged.

10vertical position.jpg This is the head rotated 90 degrees to the vertical position. The two trunnions are well aligned as the head rotates very smoothly and easily and there is only .005" clearance in the trunnions. I will be using 5 inch index plates so they clear the table when rotated to this position. Six inch plates would work but are close.

So far , I have $50 in making this head and I have the plates, the chuck , the back plate for the chuck, and if I skip buying the brass I want for the handle and sector arms ( which my budget says I may have to do), I have everything to finish this project on hand.

Tomorrow, I start the index plates.
 

brav65

Active User
H-M Supporter - Gold Member ($25)
Joined
Sep 24, 2014
Messages
925
Likes
490
#57
Awesome Mark. I am like a kid in a candy store when I see you post on your projects. Thank you!
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#58
Thank you all for the kind words and following the adventures.

I post these projects hoping to show that you all can build the same quality tooling inexpensively... oh the heck with it ...CHEAPLY ... with standard hobbyist machines. I wanted ... and I think most of us would like ... to own a dividing head , but can't lay out hundreds of dollars for one. Yes, I built this on a shoestring budget for about $50 , but buying the material and using scraps it can still be done a LOT cheaper than buying one. Plus there is a lot of satisfaction in using machines and tooling you make yourself.

There is still much left to do on this project, so keep watching and I hope someone is learning from these projects.
 

mark_f

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
May 2, 2014
Messages
2,112
Likes
2,591
#59
Well... I decided to start the index plates. They will be a long and tedious process, especially drilling all those holes. I will make the first set of holes in one plate and the dividing head will make its own hole circles in the plates after that. By doing this, they will be extremely accurate. In fact , i read that if you drill the first set of holes and use them for the head to make the rest from it, the new holes will be 30 times more accurate than the first one you make. So if I take great care to make an accurate set of start holes, the plates resulting will be more accurate than I have the ability to measure. Anyway... on to the work for today.

stack plates to be trued up.jpg I stacked four 5" round plates 1/4" thick on a 1/2" bolt. After checking several bolts, I found one that spun fairly true, So I center drilled the end and stacked the plates on after drilling a 1/2" hole as close to the center of each as possible. In the photo, my tool is HSS and it wiped out immediately when it hit the torched edges of the plates. I switched to a carbide tool with a fairly large radius and it cut the scale of, then I finished with the HSS tool. The 5 inch plate stack finished a 4.900" diameter. I could have used 6 inch plates and would have but these were available and they will be just fine.

polishing and chamfer edges.jpg After the plates were trued up, each one was put on the same bolt and the edges smoothed and polished to a nice shiny finish ( I like shiny things :grin: ). I was going to polish to a mirror finish but figured they are going to scratch up handling and using so i quit at an almost mirror finish ( or very shiny). This head is nice looking, but it ain't a show piece. It WILL get used.

drilling mounting holes in plate and hub.jpg The next step was to mount the hub from the dividing head into the lathe and using my drilling jig I made , drill the three mounting holes in one plate and the hub at the same time. You will notice I put a tight fitting drill in the first finished hole before drilling the second hole. then i put another drill in the second hole before drilling the third hole. This keeps everything aligned. I setup my degree wheel on the back of the lathe to index the 120 degree intervals. I also drilled a 1/8" pin hole, for an alignment pin, between two of the mounting screw holes. This was because no matter how hard I try the holes will not be perfect enough to line up at any position. So the alignment pin will tell where to orient the plate for mounting. I made extremely close tolerance holes. If I oversize the holes I could get them to align in ant position, but I never like doing that, even though the close tolerance hub keeps the plate centered.

drilling stack of plates.jpg I stacked the plates , in my 4 jaw chuck to hold them on the drill press with the drilled plate on top. If you look close you can see a close fitting sleeve in the center hole to keep all the plates exactly aligned because everything here is very close tolerance and there is no room for errors. The drill follows the hole in the first plate and they will all match and be interchangeable. ( I know this because I tried each one when I finished.


The photo below is the shaft and the first half with the offset and hub which is lock-tited together forever were complicated and took many hours to machine and have all the surfaces a perfect fit. The last thin you want to do is MESS THIS UP. The largest shiny part on the right end is the hub I just drill the three mounting holes in.
1worm assembly.jpg
The three holes needed to be tapped 10-24. The first one tapped fairly easy until I got in a ways and it wouldn't go any more. So, I moved to the next hole and it is even harder to tap. So, I try two more new taps and they won't go either. THEN IT HAPPENED! ..... that little "snap"....... the freaking tap broke :cry:. and It won't come out. I was envisioning having to make this assembly all over again and I also did not have any material to make it with.:(. I spent the next two hours beating the tap with a punch and hammer and now the hub is all beat and dinged up. Looks like a total loss...:faint: ... I sat down and thought a bit and with nothing to lose, I put it in the lathe and started hacking at it with a carbide cutter, as I knew it was the only thing I have that will cut a tap. It is a good thing the hub was thick as I had to cut .150: off it to get the tap out. after re machining the banged up areas and some polishing it is as good as new ... :dancing banana:...... I so lucky! :grin:

plates on head.jpg Here is the head with the direct indexing plate and an index plate mounted on the hub. I have three index plates. I plan to mark degree graduations on the outside edge of the direct index plate, but there is no room for the numbers as it is 1/4" thick. I am thinking the numbers , if I put them on could go on the back side at the outer edge .

There was one more thing that was still bugging me. That .009" end play in the worm shaft. I had a piece of brass with a 1/2" hole in it so..... If you want something difficult... try machining a .008" thick washer for a shim. I took a couple tries, but I finally was able to part of a .010" thick one and stuck it to a piece of tape to hold it while I rubbed it on a file until it was .008" thick.
shim on shaft.jpg If you look close, you can see my little shim washer behind the e-clip. Now there is virtually no end play in the shaft. With the worm adjusted right this head is really tight, no detectable play and it still turns very smooth. That is what paying close attention too tolerances will do.
The next thing to address probably should be the spindle brake as it will be needed to use the head to make the index plates.
 

rwm

Active User
H-M Supporter - Gold Member ($25)
Joined
Mar 25, 2013
Messages
1,311
Likes
1,463
#60
Mark-this is awesome! A great design and it looks great too. I'm not entirely sure this is a dividing head that "anyone" can build. You just have the skills to make it look easy! Nevertheless I may give it a try. But I'm not makin' no 0.008 shims!
R
 
[6]
[5] [7]
Top