Results 211 to 225 of 258
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7th Sep 2018, 09:37 AM #211Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
Thanks Bob, praise from you is praise indeed. )
The 4140 P/H is pretty tenacious stuff. It takes an *age* to lap or sand even a few tenths off. But - that is probably mostly a good thing. I have to use carbide tools to do it and spin it pretty darn fast and cut pretty darn hard - the 1hp motor in the South Bend gets a real workout. I doubt I could do it effectively with a leather belt but the serpentine makes a big difference. Certainly a good thing about it is that it takes some abuse - like in and out of chuck jaws 100 times, no marks when jaw tightening etc etc.
Thanks re spindle. I've learned a lot doing it. Though I do have to fess up. The snugness of the rear bearing is due to a slight misalignment of the rear bearing as this pic shows:
IMG_20180902_151827.jpg
If you look at about the 7 or 8 o'clock area you'll see a small gap. I've been stewing since yesterday on whether to go with this or not (as the fit is still pretty good) but I think the proper course of action is to try to remedy it. That is kind of why the 'prototype #1' thing. I could maybe leave it as it, or lap some more of the spindle to accommodate but that would just open it up more .. and besides all that .. it just ain't cricket.
Remedying it will mean making a new 'spindle' that is actually a boring bar and, using the front bearing for alignment, take a couple of thou out of the rear bearing. It hope it doesn't open up like a flower again!
... and then after that, making *another* spindle. Phew. Maybe by the time I get there that darn 1000 grit will actually arrive.
Thanks again Bob.
Greg.
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7th Sep 2018, 05:48 PM #212Pink 10EE owner
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- Aug 2008
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- near Rockhampton
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- 6,216
Nice work.
I have found what might seem daunting and you are told can only be done by a "professional" can often be done in the home shop if you have the patience and smarts.
If there is no time pressure then if it takes days to lap it to get the right results then it does not matter.
I read somewhere else, diamond lapping compound will get you a mirror finish.Gold, the colour of choice for the discerning person.
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7th Sep 2018, 08:55 PM #213.
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- Nov 2008
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- Perth WA
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- 71
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- 6,458
Greg,
If you wanted to try some diamond paste I could slip my cheap as chips collection of pastes in a post bag and get them off to you by Monday at the latest. I bought them to polish a replacement pivot I'd made for a Mahr indicator. The polishing went well, my execution of the pivot, not so well.
The pastes I didn't spend a fortune on are identical to some more expensive offerings on Amazon that have received OK reviews.
https://www.ebay.com/itm/8pcs-5-Gram...item211feb27f4
BT
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7th Sep 2018, 09:55 PM #214Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
RC, thanks,
I agree re what can be achieved in the home shop. Just look at some of the stuff people on this forum do. No doubt, with the right equipment and experience, that 0.00011" bearing to spindle clearance is a piece-of-cake to some professional, but, as you say, I have the time to give it a go .. and it might take a few weeks, and more than a few attempts, but I'll land somewhere that is acceptable. Might not be 0.00011" but the old girl won't mind. She'll be happy to be making sparks again.
Re the diamond paste, Bob, thanks, that is a very kind and tempting offer. I might see what I can achieve with the 600 grit lapping and fine wet/dry first. Ive learned a few things there so I might just see where I can take it.
I think a near-mirror finish thing is achievable with that. I could be wrong, but I have a suspicion that with a 0.0001" or so clearance some fine surface scratches to hold oil (kero) are probably a good thing. (?)
The real troubles are knowing how much material to leave on for lapping, and managing to get an accurate non-tapered cut on 18" of stock. The P/H takes an *AGE* to lap/sand so 0.002" of material left on is like 2 hours work ... and not getting small taper on 18" is hard! (yes - I even did a between centers two collar alignment before starting).
I started on the 'boring bar' today and the bearing surface on that is much better than spindle #1 - so some lessons learned.
Greg.
EDIT: Bob - I will take up that offer if okay. Sending PM ...Last edited by StrayAlien; 8th Sep 2018 at 09:40 AM. Reason: regeg!
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7th Sep 2018, 11:07 PM #215Member
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- Apr 2015
- Location
- Tungkillo, South Australia
- Age
- 87
- Posts
- 74
I just cancelled my MYUS.com service. Single packages from vendors were usually in good packaging (McMaster-Carr particularly) and MYUS forwarded them with no problems. Multiple packages were consolidated, in my case, with 3mm corrugated boxes packed with a few layers of fine brown paper and sent. One was 27lb and the other was 33lb, both had burst open and items had disappeared. They told me they use professionally trained re-packers! I'm trying USTOOZ and my first order from McMaster-Carr is on its way.
Charles
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10th Sep 2018, 08:14 PM #216Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
The rear bearing boring bar
Okay, rear-bearing boring bar being prepped.
Note the extended front bearing area. This is so that at all times during boring the bar is in contact with 100% the entire front bronze bearing. Also note the faint 'stripes' on it. It seems my lapping this time left a few microns bumpiness on the surface and this abrades (undetectable by feel) on the bronze. Lesson learned.
IMG_20180910_183633.jpg
The business end of the bar is narrowed and has the boring bit in it with two sets screws - one for adjustment and the other to lock the bit. I'll likely narrow that further for chips clearance.
IMG_20180910_183656.jpg
The intention is to use the auto-downfeed on the BP to do the boring. Bless the adjustability of the BP head. I can sit the grinder head on the flat on the table over to the side and position the spindle above it. I need to modify the end of the boring bar to be held in a collet. You may recall that the spindle axis in the head is *not* aligned with any 'reference' surface on the head ... so .. bless the BP again, I'll use the 3 axis head adjustment to get the BP spindle in line with the workpiece boring-bar 'spindle' - rather than the other way around.
IMG_20180910_184039.jpgIMG_20180910_184245.jpg
I'll use my made-for-the-first-boring-attempt-differential-thread end cap as the lower spindle cap as it has a through hole and I can vacuum out chips while boring.
Well .. that is the plan anyways ... well, as of today at least. Slurp.
Greg.
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29th Sep 2018, 01:38 PM #217Golden Member
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- Aug 2015
- Location
- Melbourne, Australia
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- 843
this isn't going well ...
Hi all,
The boring of the rear bearing worked well .. until I removed the bearing from the head:
MVIMG_20180922_171755.jpg
Darn! The sodding thing opened *more*. So, I figured it was time to make some wider shims. These would be a very snug fit at both ends - even to the point of opening it up a little to have the bearing pinch on them to keep them in place. It took a few hours of delicate work to get the new shims the shape and size for snugness at both ends.
Then I gave boring another go ... and ...:
IMG_20180929_083507.jpg
WHAAATTT!!! This ain't fair. So, life is telling me something. I'm planning what I do next, but it might be to make a new totally bearing with no shims and bore that.
IMG_20180927_220602.jpg
We'll see. And if the shims fall out of the front bearing again then maybe two new bearings will be needed. Keeps me off the street.
On other news, the 'basket case' magnetic chuck is now back together and feeling all magged up. I did mention that in another thread here yesterday but no pics there. Here it is for fun and giggles resting on its throne:
IMG_20180929_082426.jpg
So far, the new handle has stood up, gladly. There is a ridiculous amount of slop at the start/stop of the handle motion and that is despite the new eccentric I made n all.
IMG_20180929_082444.jpg
I did ask Peter at Magfield Engineering if I could take a pic of the equipment he uses to re-zap these guys and he obliged. The equipment is *old*. I mean my chuck is likely from the 1920's, I think his equipment may be older!
Gaze in wonder at the gothic-horror-esque beauty of it:
IMG_20180927_104208.jpgIMG_20180927_104215.jpg
Greg.
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29th Sep 2018, 07:42 PM #218Pink 10EE owner
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- Aug 2008
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- near Rockhampton
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- 6,216
The chuck zapper looks quite simple in design. I guess the DC welder powers it.
Gold, the colour of choice for the discerning person.
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29th Sep 2018, 07:56 PM #219Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
It did up to 10000 'somethings'. Maybe 'farad'? He had another that did 20000 somethings and if I recall another than did 30000. They were for zapping different materials.
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29th Sep 2018, 09:10 PM #220
Hi Guys,
That electro magnet looks awesome !
I think the word you were looking for is "Gauss", after "Johann Carl Friedrich Gauss"Best Regards:
Baron J.
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30th Sep 2018, 12:11 PM #221Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
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1st Oct 2018, 03:50 PM #222Member
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- Apr 2015
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- Tungkillo, South Australia
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- 87
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- 74
I know this post is nearly 2 years old but I buy from McMaster-Carr. All you need is a US address and they send your order immediately. There are companies that provide US addresses and I've tried 2, MyUS and US to OZ. The first has fairly quick delivery via DHL but when you need re-packaging (combining deliveries from multiple shops) they are poor. Both times I used them their box, cardboard like tissue paper, arrived open with parts missing. Insurance covered the loss but at least a month to get paid. I've just used US to OZ and the single box of MMC parts arrived OK. A little more expensive and a bit slower with UPS but I'll see what happens next time.
Charles
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4th Dec 2018, 06:27 PM #223Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
Thank Charles. I have a MyUS account that I use to get stuff from McMaster Carr. It worked last time! Re the thread being two years old. Thing is a loooong project. ) Actually, shamefully, I haven't posted for a bit. A change of jobs and and aged mother in law staying means spare time kind of evaporated. But, in the words of the (infamous) Sir Joh Bjelke-Petersen "don't you worry about that". There be more exciting action soon enough. Well ... soon-ish ....
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5th Jan 2019, 05:51 PM #224Golden Member
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- Aug 2015
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- Melbourne, Australia
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- 843
Making some progress.
Not much in terms of number of parts, but it has taken more than two weeks solid effort to make these - spindle #2 and the 'bearing boxes' to mount it in the grinder head. A few scratches etc here and there - they have been handled a lot for lapping, fitting etc. The spindle bearing surfaces are less than 0.001mm variation along their lengths. Well, smaller than the defined accuracy error of my digital micrometers anyways. Front bearing box has been lapped to give probably about 0.002mm clearance when fitted on the spindle. ' Spec' calls for 0.00011" which is about 0.003mm. I am catering for a little initial wear-in.
A big thanks to Anorak Bob for sending over his collection of diamond lapping pastes. Cheer Bob. thanks.
IMG_20190105_165810.jpg
As you can see, I decided not to make the entire bearing boxes from bronze, the new ones are 1214 with bronze liners.
IMG_20181231_151531.jpgIMG_20181231_151625.jpgIMG_20181231_151638.jpgIMG_20181231_151712~2.jpgIMG_20181231_151730.jpg
A test fit up shows things to fit, snug but things rotate okay. Next step is get the head back together and on the machine and then some slow running with lots of oil in to give an opportunity for the crests on the lapped bronze to wear down some - the non-embedding garnet paste only went to 1000 grit - which is about 40 times larger than the finishing (diamond) paste on the spindle.
IMG_20190104_154921.jpg
Greg.
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5th Jan 2019, 07:51 PM #225Most Valued Member
- Join Date
- Apr 2012
- Location
- Healesville
- Posts
- 2,129
That looks like some gr8 work there stray.
cheers, shed
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