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Thread: spin indexer
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12th Feb 2020, 06:13 PM #1Most Valued Member
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spin indexer
This thing has been sitting here for maybe a couple of years, when I got it I looked at it and thought that it was a POS so i never used it. I am hoping that i can get by using this for little jobs and get a bit more versatility between machines, my dividing head and rotary tables are a pain getting on and off machines.
I have done a bit of work to this to hopefully stiffen it up a bit, the only other person in this forum to have a go at one of these (that i could find) is Anorak Bob, his fantastic work on one of these miniature boat anchors can be found here, https://metalworkforums.com/f65/t204...-modifications
I thought i would try locking the spindle by pulling it back into a 30 deg taper, this should also give me repeatability/accuracy and removes end float. I turned a ring and lightly pressed it into the front of the body then set the body up in a 4 jaw in the lathe and cut the 30 deg taper, then cut the existing shoulder on the spindle to the same taper. I will lap the tapers together and likely re-grind the 5c taper, i will check this but i reckon it will be out.
I moved the shaft inwards and this reduced the clearance between the indexing disc and the body to about 1mm, that should take a bit of load off the indexing pin.
You would reckon there would be a shaft key? The only thing to stop the shaft spinning is the index pin that engages a hole in the index disc and a dodgy nut, no key, so it got one while i was at it.
A new nut was needed so it was made to give a bit of rigidity to the end of the shaft that the collet pushes outwards against, the shaft does not have much meat there.
The hand wheel thread at the back pulls the shaft into the taper and also pushes on the spacer that pushes on the body to tighten the spindle, I have left enough thickness on the rim of the hand wheel to drill holes should i need to get more purchase.
The hand wheel is made out of 20mm ms plate and has 50mm dia 4140 pressed into the centre and welded, i used 50mm as i wanted to keep the weld away from where the thread was to be cut,
The spacer was made out of an off cut of black pipe, i poured mig weld into each end to build it up then machined to size.
I don't like hitting things to release tapers, particularly on the grinder as it can take quite a while setting up when chasing tenths and one little tap and you have lost it, so i made a new collet draw tube with a left hand thread and cut a matching left hand thread 60mm deep in the spindle, wind the handle clockwise to tighten, wind the handle anti clockwise to release the job in the collet.
Then cut the the thread for the spindle lock in the first 20mm of the spindle.
By doing the draw bar mod i can now only get 150mm deep into the spindle with stock larger than 22mm dia, so 22mm will go right through and up to 25mm will go in 150mm.
You win some you lose some.
I don't think i am going to modify the base to suit a particular machine as i think i can just clamp it down.
cheers, shed
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12th Feb 2020, 06:50 PM #2Philomath in training
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Pete F also did one -
https://metalworkforums.com/f65/t188...ling-spindexer
Nice work though.
Michael
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12th Feb 2020, 08:31 PM #3Most Valued Member
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That's a great series on improvements I really like the taper lock!!
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13th Feb 2020, 03:38 PM #4Most Valued Member
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Thanks Ralph, not only did I want to stop the shaft from moving or rotating I wanted to eliminate chatter, or at least reduce the chance of it as best as possible, clamping it at the front of the spindle should enhance surface finish and give more accurate finishing to the required size/dimensions, sharper cutting edges ect........
cheers, shed
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15th Feb 2020, 01:33 AM #5.
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Thanks for the kind words John. You have applied your typical magic to acheive a worthwhile transformation.
One thing, my understanding is that the indexing ring is rotatable (keyless) on the spindle to allow the spindle to be adjusted into position or fine tuned, independant of the indexing ring. These indexers were primarily intended for use with grinders. I modified mine to take advantage of its lower centre height, providing an alternative to my mill's Z consuming dividing head. There was no way that the spindle wouldn't rotate if the only means of securing the indexing ring to the spindle was the threaded collar hence the split cotter clamp.
Bob.
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15th Feb 2020, 02:15 PM #6Most Valued Member
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Thanks Bob,
Often/sometimes an improvement to one function of a tool can be a detriment elsewhere, I weighed up the loss of being able to rotate the shaft in relation to the indexing ring and felt that for my use I would rather have it keyed to eliminate any chance of slippage.
I think that mostly this tool will hold cylindrical parts and these can be rotated into position before tightening the collet, I have no intention of buying collets to hold square and hex. But I do have a need for holding hex bar and also maybe gripping cylinders from the inside so I have ordered a 80mm 3 jaw, it will be a smaller version of the chuck in the pic below, It will be held with a 28mm collet, this can be positioned to the indexing ring also, oh yeah...and make a better handle to get more torque on the draw tube.
If the 3 jaw chuck is successful then I might also do a 4 jaw in the same manner.
The 100mm 3 jaw in the pic is a bit big and not good enough to be worth the effort.
My punch former has a v block so can hold odd shapes and it can be adjusted this way and that way, when on the t&cg it is quite versatile and accurate for short length jobs like cutting tools, it is pictured with with diamond dresser mounted for radiusing grinding wheels.
cheers, shed
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15th Feb 2020, 08:24 PM #7.
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Yes it is a swings and roundabouts thing. I'm sure there are numerous enhancements that can be made to these spin indexers*but with the cheap Chinese version you are starting with a sow's ear IMO.
I did make one additional accessory for mine, a dovetail spigot that enables the indexer to be mounted on a number of the Hercus tool and cutter grinder attachments, allowing it to swivel.
* Tom"Oxtool" Lipton has a number of YouTube videos showing the enhancement of the spin indexer's indexing capabilities.
Bob.
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5th Mar 2020, 06:36 PM #8Most Valued Member
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chuck and backing plate
G/day all.
I thought I would make it adjustable and while I was at it make so that it can be offset up to 5mm if need be, so 10mm
over a diameter.
It is not quite finished but you should get an idea of how it is to function from the pics, it sorta reminds me of a
British Bulldog.
I have not tested it yet in any way and that will have wait for a few days.
It looks to me that the work is gunna be a bit to far from the spin index body so I might have to make some sort of steady
if surface finish is unacceptable, time will tell.
cheers, shed
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6th Mar 2020, 10:32 AM #9.
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Looks good J !
After the required clean up, what is your impression of the Sanou chuck? And while your backplate provides the ability for offsetting, how easy is it to accurately centre the chuck after offsetting?
BT
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6th Mar 2020, 08:53 PM #10Most Valued Member
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G/day Bob, I wasn't planning on getting into the shed today but I read your post on the way home and felt that I too needed to know how well/easy that the chuck is to centre, and I also wanted to know how good/bad my backing plate is so.......
The chuck is not bad for 70 bucks, I didn't expect it to be too flash and had planned to make an adjustable backing
plate to accommodate for a dodgy chuck.
When I pulled it out of the box I measured it front to back in 4 places 90 deg apart with an excellent Mitutoyo Digital mic, shocked and disbelieving my eyes I measured it again....... one spot measured .003mm.... smaller that the other 3 measurements, the other 3 measurements were spot on the same, a good start......
The jaws are not firm in the slots but they are not loose, the pinion gears are a bit rough but they only turn the scroll and the
finish on the scroll looks excellent and its bore is a very nice smooth fit on the chuck body, the gear teeth on the back of the jaws
are ground and look accurately finished.
Jaw accuracy, undetermined at the mo.
The theory is to have the 3 chuck bolts just barely nipped up and adjust the 4 bolts on the periphery of the backing plate as you do with a 4 jaw chuck, then when close to centre nip the chuck bolts up a bit check and adjust again, nip the chuck bolts up a bit more and check and adjust again....I did say in theory......
So after about five minutes I realized that I was chasing my tail as I couldn't get repeatably closer than a thou??????
The penny dropped....sh#t on the taper, I loosened the knurled lock nut at the rear and got a bit of clearance to get into the taper and pulled a clean white rag around the taper, it came out covered in black so I gave it a bit more of a clean and put it back together with the inner taper still dirty, where that came from I don't know?? Getting sillier I spoze.
So I guess that with a proper clean it should be accurate enough for light cutting and drilling, hopefully it is good enough to use on the grinder.
I had to be somewhere else so I quickly shot this clip, the indicator is an Interapid .0005"
In the clip you will see the indicator needle move quite a bit, when I tighten the spindle lock the needle returns to zero (or at least close to it) as the tapers engage.
I turn the chuck and tighten the spindle lock at about 90 degree intervals.
https://www.youtube.com/watch?v=xH6UlTBzqooLast edited by shedhappens; 6th Mar 2020 at 10:26 PM. Reason: fixed measuremant
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6th Mar 2020, 09:54 PM #11Golden Member
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.0003mm is 3/10's of a micron, is the decimal point in correct location?
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6th Mar 2020, 10:03 PM #12.
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Thanks for the chuck review John.
Adjustment to centre the chuck sounds easier than adjusting a Griptru! I watched the YT clip and thought initially that the needle movement was probably due to spindle play. I'm sure mine too will provide different readings when the spindle is unlocked and locked. I haven't checked simply because there is nothing I can do about the clearance between the spindle and the bore.
Bob.
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6th Mar 2020, 10:28 PM #13Most Valued Member
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6th Mar 2020, 10:37 PM #14Most Valued Member
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