Author Topic: Another new project... a QCTP (Quick Change Toolpost)  (Read 75518 times)

Offline AdeV

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Another new project... a QCTP (Quick Change Toolpost)
« on: August 09, 2010, 04:34:14 PM »
I'm still waiting for those pesky taps to dissolve from my aluminium sump, and I can't muster up enough enthusiasm to finish off the spindle sleeve taper thing just now, so - what better than another new project :)

I was going to try to keep you all guessing as to what it was, but there's a total giveaway in one of the photos, so I'll just come clean now. It's yet another quick-change tool post... My 4-way TP drives me mad, it's a complete git to get the tool height correct, and somehow 4 tools just ain't enough.

Anyway, on with the fun. Ages ago, I picked up a roughly cube shaped lump of Mystery Steel (plain carbon steel as far as I can tell). It machines well enough once the thin layer of mill scale & rust was removed:



For those who are interested: 0.100" deep cut, approx 10-12mm width of cut, using an 18mm rough cutter. Coolant is regular cutting oil. Anyway, it took a couple of hours, but I ended up with this:



It's not quite cubic: It's about 5"x5"x4" - well, it was... it's about 4.8" x 4.8" x 3.8" now  :D



Next up, a bit of on-material C-o-C work, just to give me the rough positions of things. The centre point of the eccentric cam is punched & the circle scored, just for reference. Next up, pop it back on the mill & use the edge finder to get a datum point (the corner):



Then, use a large-ish centre drill to make the V-shaped hole I'll need for the next step:



Annoyingly, the centre drill then did what John Stevenson always says they do, and broke it's small flutes off. Grrrr. So, turn the piece upside down, repeat the edge-finder step, turn the centre drill over & pray that this side doesn't break too.... It didn't luckily, so I could move it over to the lathe:



In the pic above, I've squished the piece into the two parallels (which are up against the back of the chuck - and are obviously removed before switching the lathe on!) using the dead centre in the tailstock. This allows me to really quickly do up the 4 jaws to grip the piece nice & tight, and I can be sure that - within the sort of accuracy I need here, which is pretty slack TBH - the hole is centered. The parallels are there because, when I come to bore the hole out to dimension, I need to be able to get the boring bar all the way to the back (top) of the piece. Since the chuck centre is less than the 3" diameter I'm aiming for, I couldn't have the metal right to the back of the chuck....

Anyway, without further ado, I started drilling. Eventually, I got to the biggest drill I have. Here they all are, in the order I used them:



There's a couple of scary-big steps there, but all went well. The drill sizes are: 6mm, 8mm, 10mm, 1/2", 21/32", 3/4", 53/64", 7/8", 31/32" and 1". I kept the speed down to 190rpm to avoid throwing that block of metal anywhere... It would do a lot of damage I reckon...

Tomorrow I must re-mount the boring bar (YAWN) and open the hole out the rest of the way.

[edited title for search engines]
« Last Edit: September 17, 2010, 05:01:28 PM by AdeV »
Cheers!
Ade.
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Offline raynerd

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Re: Another new project...
« Reply #1 on: August 09, 2010, 06:39:58 PM »
:clap: :dremel: :clap: :dremel: :clap: :dremel: :clap: :dremel: :clap: :dremel:

Nice one AdeV! This is going to be a 100% definate project for me and fairly soon as well. I did start one a while ago but mucked it up on the shaper when cutting the dovetails. This time I`ll do it on the mill. That being said, I`ve no steel big enough to make it and although I like a good project  :proj: I do have others that I`d rather do, so I`m just working out by the the time I`ve purchased the steel block, it may have been worth just buying the QC tool post and making some holders! - but then where is the pride and fun in that :dremel:

I`ll be waiting and watching for your daily progress  :whip: :whip: :whip:

Offline AdeV

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Re: Another new project...
« Reply #2 on: August 10, 2010, 04:49:45 AM »
Thanks Chris :)

Quote
I`ll be waiting and watching for your daily progress

Hmm, it won't be daily for long.... I swan off on 2 weeks holiday after the weekend, so I may not have it finished by then... will try to, though.
Cheers!
Ade.
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Offline madjackghengis

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Re: Another new project...
« Reply #3 on: August 10, 2010, 07:44:04 AM »
I'm still waiting for those pesky taps to dissolve from my aluminium sump, and I can't muster up enough enthusiasm to finish off the spindle sleeve taper thing just now, so - what better than another new project :)

I was going to try to keep you all guessing as to what it was, but there's a total giveaway in one of the photos, so I'll just come clean now. It's yet another quick-change tool post... My 4-way TP drives me mad, it's a complete git to get the tool height correct, and somehow 4 tools just ain't enough.

Anyway, on with the fun. Ages ago, I picked up a roughly cube shaped lump of Mystery Steel (plain carbon steel as far as I can tell). It machines well enough once the thin layer of mill scale & rust was removed:



For those who are interested: 0.100" deep cut, approx 10-12mm width of cut, using an 18mm rough cutter. Coolant is regular cutting oil. Anyway, it took a couple of hours, but I ended up with this:



It's not quite cubic: It's about 5"x5"x4" - well, it was... it's about 4.8" x 4.8" x 3.8" now  :D



Next up, a bit of on-material C-o-C work, just to give me the rough positions of things. The centre point of the eccentric cam is punched & the circle scored, just for reference. Next up, pop it back on the mill & use the edge finder to get a datum point (the corner):



Then, use a large-ish centre drill to make the V-shaped hole I'll need for the next step:



Annoyingly, the centre drill then did what John Stevenson always says they do, and broke it's small flutes off. Grrrr. So, turn the piece upside down, repeat the edge-finder step, turn the centre drill over & pray that this side doesn't break too.... It didn't luckily, so I could move it over to the lathe:

 :bugeye:  AdeV, I always use the smallest center drill I think will work, while rotating the work or drill as fast as possible, with a very light touch, hoping to get a single edge cut, as that establishes an accurate center, and only then move up in center drill size.  I have also found that with magnifying "optivisors" I can re-sharpen the small edges of the center drill pretty accurately, and keep them cutting cleanly.  This is something I've only recently began to do, having too many experiences with broken off center drills.  Keeping the center drill sharp, and letting it essentially single point the center has saved lots of center drills in the past couple years and improved my accuracy of hole location. :poke: mad jack



In the pic above, I've squished the piece into the two parallels (which are up against the back of the chuck - and are obviously removed before switching the lathe on!) using the dead centre in the tailstock. This allows me to really quickly do up the 4 jaws to grip the piece nice & tight, and I can be sure that - within the sort of accuracy I need here, which is pretty slack TBH - the hole is centered. The parallels are there because, when I come to bore the hole out to dimension, I need to be able to get the boring bar all the way to the back (top) of the piece. Since the chuck centre is less than the 3" diameter I'm aiming for, I couldn't have the metal right to the back of the chuck....

Anyway, without further ado, I started drilling. Eventually, I got to the biggest drill I have. Here they all are, in the order I used them:



There's a couple of scary-big steps there, but all went well. The drill sizes are: 6mm, 8mm, 10mm, 1/2", 21/32", 3/4", 53/64", 7/8", 31/32" and 1". I kept the speed down to 190rpm to avoid throwing that block of metal anywhere... It would do a lot of damage I reckon...

Tomorrow I must re-mount the boring bar (YAWN) and open the hole out the rest of the way.

Offline AdeV

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Re: Another new project...
« Reply #4 on: August 10, 2010, 10:25:02 AM »

 :bugeye:  AdeV, I always use the smallest center drill I think will work, while rotating the work or drill as fast as possible, with a very light touch, hoping to get a single edge cut, as that establishes an accurate center, and only then move up in center drill size.  I have also found that with magnifying "optivisors" I can re-sharpen the small edges of the center drill pretty accurately, and keep them cutting cleanly.  This is something I've only recently began to do, having too many experiences with broken off center drills.  Keeping the center drill sharp, and letting it essentially single point the center has saved lots of center drills in the past couple years and improved my accuracy of hole location. :poke: mad jack


Hi Jack,

That's definitely what I did wrong with the first hole, I only had 550rpm on the spindle. I upped that to 1200 or therabouts for the 2nd hole. Most of the time, I reckon I can just use a stub drill for hole location (in the future), but this is one time when I actually needed a real centre drill...

Thanks for the info on sharpening; this is something I've not yet dared try my hand at... I still have loads to learn before I try sharpening drills & end mills...
Cheers!
Ade.
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Offline AdeV

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Re: Another new project...
« Reply #5 on: August 10, 2010, 04:02:28 PM »
Just a brief update today, I didn't get anywhere near as far as I wanted to :( Why is it the clock moves fastest between 6pm and 9pm?  :scratch:

Anyway... Due to the unique way my boring bar is shaped (it came with the lathe), I have to send it into holes at quite a steep angle. So I can't bore the hole to full depth (about 3") in one continuous go, I have to take maybe 1/2", then I can get the tool a bit further in, and so on... Because of this, I need to know where to stop when deep in a hole (this would be true if I was taking the full depth in one go also); so an indicator is stuck to the swarf tray on its mag base:



When the indicator reaches zero, disengage feed, or suffer the consequences...

Here's the hole coming along. It's slow, tedious work. I like the mill better...



More tomorrow...
Cheers!
Ade.
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Offline Brass_Machine

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Re: Another new project...
« Reply #6 on: August 11, 2010, 03:10:13 PM »
Nice start to your project Ade! I am sure this will be as fantastic as your soon to be completed oil pan.  :headbang:

Eric
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Offline AdeV

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Re: Another new project...
« Reply #7 on: August 12, 2010, 04:23:35 PM »
Thanks Eric, I don't think it'll be quite as unique somehow, except maybe its size... It's a big boy...

Nothing done yesterday, work interrupted play. I got another 3 hours at it tonight:



The big hole is about 1" deep by 2.8" diameter. The inner hole could be anything, I haven't measured it yet. I will have to adjust the tooling setup before I can complete this hole to full depth:



As you can see, with the boring bar at full depth in the hole (around 2.2"), there's sod all room left before the tool that's on top of the boring bar hits the work piece, causing all kinds of aggro. It's this sort of stupidity that I'm looking forward to curing with the QCTP...
Cheers!
Ade.
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Offline AdeV

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Re: Another new project...
« Reply #8 on: August 13, 2010, 06:29:19 PM »
More boring...




Eventually(!):



That's 2.830" in diameter, and 2.725" deep. It's probably taken 9hrs to hollow it out.... I was planning to go to 3" diameter, but given how long it's taken to get this far, I may stay at 2.83" & simply make the eccentric a little smaller...


Of course, part of the problem may be my bizzare-looking boring bar. I've not seen anything ground like it anywhere else; it came with the lathe, and other than occasionally sharpening it, I've not changed its shape. Any thoughts gratefully welcomed:



Getting right into the corner of a hole isn't possible with this tool; if you cut straight in, then the bottom right edge cuts; if you angle it over sufficient to avoid that, then the top left part of the tool bangs into the back of the hole before the cutting edge....


Cheers!
Ade.
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Offline andyf

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Re: Another new project...
« Reply #9 on: August 13, 2010, 07:13:47 PM »
Hi Ade,

It probably started life more this sort of shape, so its shank could be set parallel to the lathe's axis, but repeated sharpening has removed the part outlined in red. I think it's time to raid the piggy bank and treat yourself to a new one.



Andy 
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline AdeV

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Re: Another new project...
« Reply #10 on: August 13, 2010, 08:13:24 PM »

It probably started life more this sort of shape, so its shank could be set parallel to the lathe's axis, but repeated sharpening has removed the part outlined in red. I think it's time to raid the piggy bank and treat yourself to a new one.




Thanks Andy - that certainly makes more sense than the tool being the shape it is from new... I'll waste no more oilstone on it  :D

Damn, I just put in an order with Chronos.... but OTOH it looks like RDG have some nice boring bars... so... 16mm or 20mm...?
Cheers!
Ade.
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Offline Ned Ludd

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Re: Another new project...
« Reply #11 on: August 13, 2010, 10:14:37 PM »
Hi AdeV,
Nine hours boring, that must have been truly boring.  :lol:

I do think you have to revise your methods and quickly.

I was going make a recommendation for a tip, but on looking at current on-line catalogues for Iscar and Sumitomo, the ones I use are not to be found, curse this craze for modernizing everything. Anyway, the ones I would have recommended are truly magnificent. They allow a near chrome like finish, even with very small depth of cut, on all the metals that I use. I shall have to be careful with my remaining stock, as replacing them might prove difficult. :( :(
Ned
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Offline AdeV

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Re: Another new project...
« Reply #12 on: August 14, 2010, 03:17:32 AM »
Hi AdeV,
Nine hours boring, that must have been truly boring.  :lol:

I do think you have to revise your methods and quickly.


The main reason it's taken so long, other than the general lack of time/day I have at the machines, is the smallness & slowness of the cut I have to take with the boring bar, plus the frequent requirement to stop & clear out chips. For example, I absolutely dare not push it past a 0.020" cut, at quite a slow feed rate (my lathe quotes 160cuts/inch, whatever that works out to in thou per revolution). I started at 190rpm, but was down to 112rpm by the time I was out at the quoted diameter, simply due to the heat being generated by the cutter bit... I can only take so much cutting oil smoke.

At least 45 mins, maybe 1hr, was spent facing the back face of the cut, as best I could, with the bar over at an angle, I can't get right to the corner of a cut as previously mentioned, so the bottom of the hole tended to form a bowl shape. Then you have to factor in some time to re-arrange the tooling in the toolpost (+ I got some extra shims to bring the tool to absolutely smack on centre height, it was a smidge below when I started). So add 1/2 to 1 hour for that... and before you know it, you've got 9 hours invested in the piece. Hence my internal debate about going to the full 3" or not: It's not essential, so I don't think I will. Instead, I'll turn the extra off the S/S bar I have. I have some carbide tipped turning tools, so I should be able to attack the cut quicker than boring out the hole....

Quote

I was going make a recommendation for a tip, but on looking at current on-line catalogues for Iscar and Sumitomo, the ones I use are not to be found, curse this craze for modernizing everything. Anyway, the ones I would have recommended are truly magnificent. They allow a near chrome like finish, even with very small depth of cut, on all the metals that I use. I shall have to be careful with my remaining stock, as replacing them might prove difficult. :( :(


How about a photo? And maybe the tip type?  :)
Cheers!
Ade.
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Offline madjackghengis

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Re: Another new project...
« Reply #13 on: August 14, 2010, 09:13:19 AM »
Hi AdeV, the easy way is to put a torch to your boring bar, remove the small piece of carbide, and replace it with a much larger one, which you can grind to match the picture you show of Andy's suggestion.  The long way is to get a boring bar that takes inserts, as it will cut better, and will have good chip control, something difficult to accomplish with the plain brazed bar.  Good chip control can double or triple your boring speed if the edge is right.  The one I use most has a TPG insert, and gives a good finish, and empties the cavity pretty well when there's room. :thumbup: mad jack

Offline AdeV

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Re: Another new project...
« Reply #14 on: August 14, 2010, 10:08:48 AM »
Hi AdeV, the easy way is to put a torch to your boring bar, remove the small piece of carbide, and replace it with a much larger one, which you can grind to match the picture you show of Andy's suggestion.  The long way is to get a boring bar that takes inserts, as it will cut better, and will have good chip control, something difficult to accomplish with the plain brazed bar.  Good chip control can double or triple your boring speed if the edge is right.  The one I use most has a TPG insert, and gives a good finish, and empties the cavity pretty well when there's room. :thumbup: mad jack


Hi Jack - that boring bar is plain HSS! No carbide in sight...

I'm going to order a couple of indexable boring bars - a big one for big holes & a small one for, well, I'm sure you get the idea :) RDG do a fine looking selection all the way up to 20mm...
Cheers!
Ade.
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Offline AdeV

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Re: Another new project...
« Reply #15 on: August 14, 2010, 11:08:57 AM »
After hmming and hahing for a while, I decided what the heck; clean up the bore & consider it done. So, I set to with the wet & dry, but got bored after a while, and my fingers hurt.... so, I had a brainwave. (It'll end in tears -ed)

I figure, a tumble polisher tumbles various steel (or whatever) parts together, ideally with a lightly abrasive medium. Well, I didn't have any abrasive medium handy, but I did have a handful of mixed nuts:



I figured, the nuts being harder than the bore, the bore should be the one to take the wear. With enough knowledge to be dangerous, I tape up the holes:


And sent it for a spin:



After a couple of hours, and with more than a little trepidation, I opened her up for a look:



Not bad! Not perfect, some abrasive stuff would probably help. So, I chucked some extra nuts I'd found in, sealed 'er up & set 'er off again. A couple more hours later:



Not much difference. I think I've reached the limit of what I can do with my nuts. I think I'll move onto the cam next, see how far I get with that...
Cheers!
Ade.
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Offline AdeV

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Re: Another new project...
« Reply #16 on: August 14, 2010, 03:20:59 PM »
One last photo for today:



As you can see, the new toolpost will stick forwards of the old one a little way, even before I add any tool holders... therefore, I might push the dove tails back 1/2", to give me a bit more breathing space by either dovetail.

Hopefully, I'll have some time in the shed tomorrow, before I swan off for 2 weeks. Don't think I'm going to get it finished before I go away somehow...


Edit: Does anyone have a large (BXA?) toolpost? If so, can you please measure the dovetails (widest & narrowest parts)? I've googled & googled and I can't find a single reference to the _actual_ dimensions of these toolposts... It occurs to me, if I make my dovetails the same size as a commercial item, at least I could buy toolholders instead of having to make them, should I become lazy and rich in my old age...
« Last Edit: August 14, 2010, 03:26:55 PM by AdeV »
Cheers!
Ade.
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Offline Divided he ad

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Re: Another new project...
« Reply #17 on: August 15, 2010, 07:33:49 PM »
Can't believe you used your nuts for that!!   :jaw:   :lol: 


I'd have thought that the centrifugal force would have kept them all to one side?  How fast was it spinning?

Doesn't a tumble polisher move slowly with as stated "abrasive stuff"  doing the work over many hours?


Just wondering.... Never tried it myself.



Looking good though Ade  :thumbup:



I'm no help what so ever on the technical dimensions question though sorry  ::)





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Offline jim

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Re: Another new project...
« Reply #18 on: August 16, 2010, 01:32:51 AM »
just a thought on this polishing the bore, why not chuck some bits of grinding wheel in with the nuts??
if i'd thought it through, i'd have never tried it

Offline Bluechip

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Re: Another new project...
« Reply #19 on: August 16, 2010, 05:25:28 AM »
Can't believe you used your nuts for that!!   :jaw:   :lol: 


I'd have thought that the centrifugal force would have kept them all to one side?  How fast was it spinning?

Doesn't a tumble polisher move slowly with as stated "abrasive stuff"  doing the work over many hours?


Just wondering.... Never tried it myself.



Looking good though Ade  :thumbup:



I'm no help what so ever on the technical dimensions question though sorry  ::)





Ralph.

Bit  :offtopic: but, as I made a couple of tumblers as a lad ..

They do run quite slowly, about  some 60 - 120 RPM is typical for a 4-6" drum.

If you want a cheap abrasive, get some 'Sharp Sand' from the DIY shed/builders merchant. NOT soft yellow/red building sand, that's useless.
Sharp sand is nowhere near as good as Carborundum grit, but it's nowhere near the price either.  ::)
Use it wet with a dash of liquid soap.

'Many hours' Ralph ??

Days or weeks for pebble polishing  :(

Nice shiny nuts though. Mine are rusty. I'm jealous ...  :lol:

Dave BC




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Offline AdeV

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Re: Another new project...
« Reply #20 on: August 16, 2010, 02:53:05 PM »
OK, a quick update now I'm in "sunny" Spain...

Thanks for the thoughts on the tumble polishing.... I was running at 112rpm for the most part, basically, I just picked a speed where I could hear my nuts rattling around & left it at that. I will try some proper abrasive next time, I didn't have any to hand hence not including any...

I've also turned a lump of 3.5" 303 stainless steel down to roughly the same diameter & depth as the hole. At the moment, I think it's a touch too tight to just slip smoothly in, so I may need to lose another couple of thou. Just out of interest, what sort of dimensional difference does one need to ensure a nice sliding fit that isn't so tight it jams up?
Cheers!
Ade.
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Offline Brass_Machine

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Re: Another new project...
« Reply #21 on: August 16, 2010, 04:17:48 PM »
O...I just picked a speed where I could hear my nuts rattling around & left it at that...

Now I have to clean my keyboard. Soda everywhere!   :lol:

Enjoy Spain.

Eric
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Re: Another new project...
« Reply #22 on: August 20, 2010, 06:01:40 PM »
O...I just picked a speed where I could hear my nuts rattling around & left it at that...

Now I have to clean my keyboard. Soda everywhere!   :lol:

Enjoy Spain.

Eric
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :doh:


Rob

Offline AdeV

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Re: Another new project...
« Reply #23 on: September 03, 2010, 04:55:41 PM »
Onwards!

Unseen by you ('cos I didn't take any photos of it, oops), I had turned a length of 3.5" s/s bar down to the correct diameter (nearly - I was a couple of thou over) for the toolpost. On returning from my 'oliday, I ordered a fab new boring bar to replace the knackered one I've been using, and got on with finalising the diameter & drilling the centre hole as far as I could.

Yesterday, the spiffing new boring bar turned up; but it needed quite a shim to fit in the existing toolholder.... it was a whopping 0.410" low (measuring from tip to dead centre)! So, I made a 0.405" "shim" from some scrap 1/2" steel - which, it turns out, is exactly the right height  :thumbup:

Here's the new toy:



I took a couple of trial cuts through the drilled hole, got some chatter on the first pass, but second & subsequent passes were as smooth as you like. Spot the happy bunny :)

So, after cleaning up the drilled bore a bit, I decided to clean up the shoulder:



You can see the chatter marks (LHS shoulder, nearest the chuck); that's because, not having any tools which will cut to a shoulder just now, I used the boring bar. To make it work, I had to have the cutter behind the work piece, and run the lathe in reverse. Other than the slight chatter, it worked like a champ.

The strange looking "shoulders" on the bottom (RHS) are to cope with the fact my old boring bar couldn't cut a clean bore to a shoulder, so there's a bit of excess material left in the main toolpost body. Those cuts clear that, so it goes and sits right at the bottom.

Next jobs: Open the centre bore out a little further, then off-set the piece & cut the cam (I may need to grind a tool up for that, as it will be between two shoulders...), then finally turn it round & relieve the top, cut a nice taper on the "handle" section, drill & tap for the handle...

I should probably do some proper measuring soon... Nah, what the heck. Keep on cuttin'!
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline AdeV

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Re: Another new project...
« Reply #24 on: September 04, 2010, 03:11:19 PM »
So, today I wanted to finish off the cam lock bit. First job was to tidy up the main bore & open it out to 1.5".

This done, the next job was to off-set the work to cut the actual cam part. This achieved, I also scrounged up some weird turning tool from the bottom of a drawer somewhere. I think it's a left-handed tool to cut to a shoulder, but ignorance is bliss so I gave it a quick whizz on the carbide grinder wheel, just to sharpen it up, lobbed it in the toolpost (fortunately, no faffing required, it went straight in at the right height), and got busy with the cutting:



Yes, I know the tool looks like it's mounted on its side. I took me ages to work out which way up it went...

One thing about this tool, it cuts a very nice surface on 303 Stainless. The entire piece was now turned around, re-centered, a few touches removed from the main diameter just to get it to run true; then I cut a 20 degree taper. This is where the handle will go, and matches the taper on my current toolpost. After a bit of faffing (including re-setting the piece, as it moved a smidge when the taper was being cut, somehow), everything was ship-shape. A quick file to take the burrs off, and a quick whizz with some oiled-up wet & dry paper made no impact on the machining marks. So I pretended it is a "brush finish" & left it at that...

Next job, drill & tap the hole for the handle. First up, I needed to somehow mount it in the milling machine, at an angle of 20 degrees, straight & true... After some headscratching, some messing about with the sine bar & gauge blocks, and discovering that the only way I could fit it into a V-block & clamp  would be if I drilled the wrong side of the piece for the handle.... I suddenly got some inspiration. Having just bought a digital angle gauge, why not simply clamp it between V-blocks in the vice, and manually tip it up until the correct angle appeared. A bit like this:





Simples.... used an end mill to make a small flat, centre drill (at max RPMs) to make a wee guide for the twist drills, drilled 4mm, 6mm, 7.5mm, 8mm & 8.5mm ready for an M10 tap.

Now.... as anyone who has read any of my stuff before will know, tapping is not something I enjoy. I'm still dissolving two taps I broke off... and that was in Aluminium; now I'm tapping in stainless steel! I've also found tapping to be an energy intensive operation, and bloody slow.


So... while I was on holiday, I noticed an auto-reversing TapMatic on eBay. Actually, there were several (of various makes), all going for around the 100 mark; one was on Buy-it-now-or-best-offer, so a cheeky offer of 75 was, to my surprise, accepted promptly  :headbang: I also bought some spiral point taps, which I believe are better for power use than regular hand taps.

Anyhoo, pop the tapping head on the mill - it uses up all my headroom, I could only just fit everything on!  :bugeye:



So, here's how to tap in Stainless: Line everything up. Set speed to 115rpm. Hold quill handle with right hand, use left hand to release quill lock (oh for a working quill spring...). Hold torque lever with left hand. With other left hand, switch mill on, then apply a load of cutting oil. Pull quill handle down until tap engages & starts tapping. Keep gentle downward force on until tap comes out of the other end of the hole; then pull quill up. Tap reverses & drives itself out of the hole. From first pulling the handle down to the tap fully withdrawing - 10 seconds (approx). MILLIONS of times easier than farting around with the tap, tap handles, trying to make it all run true. Yada yada. I am SO going to love this tapping head, even if it is too deep for the mill. I can always use it on the pillar drill instead.

Anyway, that's more or less where I left it. The cam piece is now finished, I have the main holding sleeve & bolt to make, the pistons to make, the body to finish off, and the base to make. Blimmin' eck!

Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73