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Post by springcrocus on May 26, 2018 6:38:21 GMT
I've kicked this off to prevent Roger's thread getting cluttered Toolmaker's jacks are very useful, and an interesting small project for a less-experienced machinist to have a go at and get something useful at the end. Malcolm (of the Hunslet build) diplayed his pair on the forum a while back but I'm reluctant to suggest he describes them in more detail because, with the level of apathy frequently displayed on this forum, it may well be a waste of his time.  I'd love to be proved wrong, however, so maybe a few members would like to contribute something - a design, maybe, or ideas about support methods? Regards, Steve |
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Post by Roger on May 26, 2018 7:40:35 GMT
Can I kick off with a list of attributes I'd like these to have?
1) To be as versatile as possible, they should be able to adjust into as low a height as reasonably practical. Making up distance is easy, so spacers can do that. The amount of adjustment probably doesn't need to be any more than the smallest spacer.
2) They should be compact so they can be used where there isn't much room.
3) An attachment for accessories to increase the versatility could be incorporated from the start. That might just mean having separate supports that screw in.
4) Use a locking nut (if there is one) that uses the same spanner as the rest of the clamping set if it's about that size, or use a knurled ring.
5) Possibly allow for the jack to be clamped to the bed for extra rigidity. That could just be a small flange on the base
6) Think about how and where they will be stored.
I'm sure there are other things that could be incorporated. I try to think of everything, however unlikely, right at the start because sometimes a little gem of an idea comes up.
Another idea is to make a very low profile adjustable support where there's not enough room to get a traditional style in. Something with a pair of shallow wedges comes to mind. Something with say 6mm-10mm total height and an adjustment of say 0.5mm - 2mm I would envisage this being made in at least a couple of sizes.
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Post by simplyloco on May 26, 2018 8:13:51 GMT
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Post by springcrocus on May 26, 2018 8:43:07 GMT
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rrmrd66
Part of the e-furniture
Posts: 339 
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Post by rrmrd66 on May 26, 2018 9:26:50 GMT
Hi Steve Apathy? Not here in North Yorkshire! Here they are. the original set made around 1967. Wrapped in an oily " wiper" and put in the old folding tool box to see the light of day last year. Not bad nick, don't you think?
Not quite to Rogers new updated spec but not far off. They have proved to be so useful especially with machining castings where the cast surface is not inducive to good clamping.
The four screwed attachments have a conical section with a flat top (sorry my quick snap doesn't show this.)
I would imagine that the precision ID/OD cylindrical grinding might be a bit beyond most home workshops. However I wouldn't be surprised if someone, like Roger, knocks up a grinding machine next week out of his scrap bin  .
If anybody is interested I will send them dimensions and a sketch, but apologies no CAD. That would take until Christmas to do, with much tutting and gnashing of teeth.
Cheers
Malcolm
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Post by springcrocus on May 26, 2018 10:27:08 GMT
Not your apathy, Malcolm, you've got a build thread! I was more concernered that Roger, John, you and me would be the only ones at the party.  Thanks for posting that picture, it shows a good starting point - simple but versatile. Regards, Steve |
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Post by Roger on May 26, 2018 12:56:45 GMT
Hi Steve Apathy? Not here in North Yorkshire! Here they are. the original set made around 1967. Wrapped in an oily " wiper" and put in the old folding tool box to see the light of day last year. Not bad nick, don't you think?
Not quite to Rogers new updated spec but not far off. They have proved to be so useful especially with machining castings where the cast surface is not inducive to good clamping.
The four screwed attachments have a conical section with a flat top (sorry my quick snap doesn't show this.)
I would imagine that the precision ID/OD cylindrical grinding might be a bit beyond most home workshops. However I wouldn't be surprised if someone, like Roger, knocks up a grinding machine next week out of his scrap bin .
If anybody is interested I will send them dimensions and a sketch, but apologies no CAD. That would take until Christmas to do, with much tutting and gnashing of teeth.
Cheers
Malcolm
Not bad at all Malcolm. Turned tolerances are fine for this, no grinding required. I do like the spacers, I wouldn't have thought to interlock them like that, I would probably have made them as simple discs. It probably would be fine to make that top section a lot shorter, that would make it even more flexible. |
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jem
Elder Statesman
Posts: 1,075
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Post by jem on May 26, 2018 16:33:40 GMT
No Apathy with me, I am always interested in new tools and thoughts, that is how to learn, in the past I have just used bits of scrap to the height that I wanted, but now I am going to have to think about making some proper ones. So more work for me!
One thing I have made and would not be without for my milling machine is a nut spinner for the arbour pull up bolt. so that I can quickly undo the r8 arbour. Before I had to twiddle the nut on the top a slow process,often a bit out of reach. Now I can spin the nut until it just needs to be tightened with a spanner. or unspin it to get the arbour out. The nut spinner is just a round piece of aluminium with a 19mm socket fixed to the bottom of it. I also made a big tee square for the mill, this is 25 mm square so that I can line up the vice or anything else square with the table. I put slots in it so that I can also bolt it to the table with t nuts.
Perhaps we should start a thread of useful things we have made to enhance the working of our lathes and Milling machines etc.
best wishes
Jem
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jools
E-xcellent poster
Posts: 200
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Post by jools on May 27, 2018 0:05:39 GMT
Hi Steve Apathy? Not here in North Yorkshire! Here they are. the original set made around 1967. Wrapped in an oily " wiper" and put in the old folding tool box to see the light of day last year. Not bad nick, don't you think?
Not quite to Rogers new updated spec but not far off. They have proved to be so useful especially with machining castings where the cast surface is not inducive to good clamping.
The four screwed attachments have a conical section with a flat top (sorry my quick snap doesn't show this.)
I would imagine that the precision ID/OD cylindrical grinding might be a bit beyond most home workshops. However I wouldn't be surprised if someone, like Roger, knocks up a grinding machine next week out of his scrap bin .
If anybody is interested I will send them dimensions and a sketch, but apologies no CAD. That would take until Christmas to do, with much tutting and gnashing of teeth.
Cheers
Malcolm
Thats a nice little set Malcolm,
as a (very) amateur machinist I find it hard to add to Rogers list - I usually come up with suggestions after I find I can't do something as I expected ! Although in my view simple is sometimes best for basic duties and then develop a mkII for those tricky jobs.
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Post by springcrocus on May 27, 2018 6:21:39 GMT
Something that may be worth considering is the choice of thread used for adjustment. If 40 tpi were chosen then one would have a traditional imperial micrometer adjustment of 25 thou per revolution. Metric-orientated people could choose 0.5mm pitch for approx 20 thou per turn, or 1mm pitch for approx 40 thou per turn. Most model engineers will have to screwcut a 40 tpi thread at some point in their lives (standard ME thread) so would probably be a good choice. This would take the jacks to the next level, I feel.
Regards, Steve
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Post by Roger on May 27, 2018 6:32:12 GMT
"This would take the jacks to the next level" nice one Steve.
It's a good point about the pitch, and I think a fine pitch is preferable to a coarse one because the locking action would be greater if you use a knurled locking nut.
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rrmrd66
Part of the e-furniture
Posts: 339
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Post by rrmrd66 on May 27, 2018 7:03:08 GMT
Good Morning to you all (wherever you are)
That is a good suggestion about a 40tpi thread, although I wonder if it would actually be of use? A finer thread form, yes, but 40tpi starts entering the realms of a measuring instrument.
Remember that when these were made the objective was to test our ability in turning, knurling,taper turning, screw cutting,(1/4"BSW,I think), parting off, heat treatment, cylindrical grinding (internal and external). I don't think I ever learned about ME threads until two years ago. Certainly not in the 60's.
I like the idea of a foot to lock it to the mill bed. They do have a tendency to skate around a bit.
The big plus point for me is when trying to produce horizontal flat surfaces on the mill and the underside of the casting is like the surface of the moon they just screw straight into place whatever the height you require and add the require support.
Keep the suggestions coming guys.
Cheers
Malcolm
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Post by Roger on May 27, 2018 8:40:51 GMT
Hi Malcolm,
I agree that knowing the thread pitch isn't necessarily useful, but it just might be.
If a design is going to the clamped to the bed, it might be a good idea to lock the spacers to each other. That could simply be a matter of threading the pieces you've shown, another exercise in screw cutting!
I don't think you can assume that there will be much force clamping the job onto the jack.
Another thought is whether the jacks should have attachment points for any kind of clamping system to hold the supported part?
Vee a blocks usually come with a bridging piece that allows parts to be held on them. I suppose a couple of threaded holes in the top piece could allow for something to be attached for that purpose.
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rrmrd66
Part of the e-furniture
Posts: 339
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Post by rrmrd66 on May 27, 2018 9:37:08 GMT
Hi Roger
Yes you are right. I have always used my jacks when there is a strap/clamp, or something similar, creating a downwards clamping force. It's just that they can accommodate the rough castings "underside".
I have a set of finished Vee blocks and part machined stirrup shaped holders. The number of times I have wished I had finished them up when cross drilling a rod, for example.
So the attachment you suggest would be more than worthwhile, assuming you can anchor the base of the jack to the milling table
Cheers
Malcolm
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jools
E-xcellent poster
Posts: 200
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Post by jools on May 27, 2018 21:44:27 GMT
Is it possible to incorporate a magnetic base that would help to stop it skating around ?
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Post by simplyloco on May 27, 2018 21:50:02 GMT
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rrmrd66
Part of the e-furniture
Posts: 339
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Post by rrmrd66 on May 28, 2018 6:33:50 GMT
Is it possible to incorporate a magnetic base that would help to stop it skating around ? Hi Jools
I like the idea of a magnet.
The downside is, with the current set, is that you would sacrifice the internal shoulder of the longest, or bottom, spacer.
Currently it is possible to construct one very long jack made up of 12 spacers nesting in one another plus a conical top.
I hasten to add that you would probably never attempt this as it would be, to use a technical term, " a bit wobbly"
Maybe a simple "thin" push fit foot, with said magnet, bonded into its base. That way you would not interfere with the ground ID, maintain adaptability but also increase adaptability.
Keep thinking guys
Cheers
Malcolm
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Post by Roger on May 28, 2018 7:38:48 GMT
I think a magnet might be a bit of a nuisance in practice because it's going to end up covered in swarf that won't be easy to completely remove. If you want it held down, I think a positive clamping arrangement would be preferable.
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peteh
Statesman
Still making mistakes!
Posts: 760
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Post by peteh on May 28, 2018 14:52:44 GMT
Rather than a strong magnet maybe use a weak one, enough to 'stabilise' the jack while adjusting the height, but easier to keep wiped clean. Could get complicated and use electromagnet - OK I'll shut up now |
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jools
E-xcellent poster
Posts: 200
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Post by jools on May 29, 2018 4:25:30 GMT
I was thinking of the switchable magnets similar to the DTI stand I use on my surface plate. They don't appear to pick up to much swarf.
They are relatively large though.
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