Author Topic: Tailstock die holder  (Read 1572 times)

Online Roger B

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Tailstock die holder
« on: August 04, 2019, 08:15:15 AM »
For a long time I have been using a cheap imperial tailstock die holder with metric dies. The fits, especially for the 20mm die in a 20.9mm (13/16) hole, were not good and resulted in some slightly undersized or tapered threads. The MT1 - 16mm mandrel seemed ok so I decided to make a new metric holder. I did think about boring and sleeving the existing body but I still have some imperial dies.

I selected a piece of close enough 35mm diameter 90mm long mildish steel bar from the shelf. This was faced both ends and skimmed to remove the brown coating. I had a long 2.5mm drill that would just go through with about 4mm to hold in the chuck and starting with a stub drill and then a normal drill I got all the way through without disaster. Next I went through 10mm and finally 13.5mm (the largest MT1 size). As the tailstock stroke is only 40mm there was a lot of sliding the tailstock in and out (just as well it has a new knob  :) )
I tried to see if I could bore from one end but the compound slide hit the tailstock. I could have made various solutions but decided just to bore from both ends.
Best regards

Roger

Online Roger B

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Re: Tailstock die holder
« Reply #1 on: August 04, 2019, 04:47:49 PM »
Having bored to 15.8mm from both ends I finished the bore with a 16mm hand reamer. There was no detectable transition/ridge in the bore and it was a good fit on the mandrel. With just residual cutting fluid as a lubricant the mandrel took several seconds to fall out under it's own weight  :) I then machined the 20mm die socket and turned it round to cut the 25mm end. Although the working ends were a long way from the chuck I found that with some gentle taps from a soft hammer I could get it running concentric to better than  0.05mm. Finally I cut some grooves like the original, I'm not sure if they serve a real purpose but I think that it looks better with them. Next step sort out some adaptors for 16mm and 12mm dies.
Best regards

Roger

Online Kim

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Re: Tailstock die holder
« Reply #2 on: August 04, 2019, 06:07:04 PM »
Nice looking die holder, Roger!
Looks like you'll be getting a much better die fit with the new one!
Kim

Offline mklotz

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Re: Tailstock die holder
« Reply #3 on: August 04, 2019, 06:34:16 PM »
It seems the only M2.5 x 0.45 dies I can find are also 20 mm diameter.  Fortunately, my homemade die holder is 13/16 on one end and 1" on the other.  I intend to make a sleeve 1" diameter with a 20 mm hole and a transverse hole to permit an extra long setscrew to pass through and lock the 20 mm die in place.

Damn the inferial system. 
Regards, Marv
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Online Roger B

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Re: Tailstock die holder
« Reply #4 on: August 08, 2019, 05:42:44 PM »
One day the world might become standardised  ::)

Next up was an adaptor for my 16mm dies. This was made from an end of 25mm bar drilled through 10mm. I opened out most of the recess with a 14mm end mill and finished off with a boring bar. I previously made an adaptor for 12mm dies that had a 20.8mm diameter that I decided to skim down to 20mm. As this was fairly narrow I supported it with a piece of 6mm ss rod held in the tailstock chuck. The last turning operation was handle from a piece of 8mm rod. I saw no point in the knurling on the original so left it plain but rounded.
To get the 45° angle between the clamping screws I decided to use the Proxxon dividing head on the Proxxon drill. For tapping I used the chuck key for added leverage.
Best regards

Roger

Offline Admiral_dk

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Re: Tailstock die holder
« Reply #5 on: August 08, 2019, 10:03:07 PM »
Looks like you will end up with at nice new tool Roger  :ThumbsUp:

Quote
One day the world might become standardised

Yeah well .... the new Brexit Government has announced that they will drop the Metric system and go back to the Infernal system in order to Make Britain Great again  :insane:   :Doh:   :facepalm:  but what do you expect from another set of morons in charge ...!... sorry I will stop here.

Offline Ian S C

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Re: Tailstock die holder
« Reply #6 on: August 09, 2019, 04:22:39 AM »
OK about going back to imperial(you never really left it), but manufacturers are all set up for metric, and your future market is mainly metric. I I suppose smeone will suggest going back to 20 shillings in a pound, 12 pence in a shilling. Maybe pounds and ounces for weight.Can't the silly B*&&^% see that changing from where you are now will put you back 50 years, an cost you for ever. Forget it.
Ian S C

Online Roger B

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Re: Tailstock die holder
« Reply #7 on: August 10, 2019, 08:12:10 AM »
 :)  :)  :)

Final step, drill and tap the 16mm adaptor. After a quick polish and Loctiting the handle in place its ready for anything  :wine1:

As an aside I realised that if I assemble the adaptors so the clamping screws are on the opposite side to those on the main body the tolerances will cancel out  ;D
Best regards

Roger

Online Kim

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Re: Tailstock die holder
« Reply #8 on: August 10, 2019, 05:23:10 PM »
Very nice little tool you made, Roger.  :ThumbsUp:

Now we need to see it in action!
Kim

Online Roger B

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Re: Tailstock die holder
« Reply #9 on: August 10, 2019, 05:32:41 PM »
Action is planned  :) I was prompted to make this due to problems with the threads on the new series of fuel injectors. The offset together with a sharp die and a brass workpiece was resulting in undersize threads which may fail under pressure  :(
Best regards

Roger

 

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