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shedhappens
29th Jul 2017, 05:05 PM
I picked up this little Repco grinder a few months back, it had a bit of vibration when I ran it so I dressed the wheel and it was still the same.
I took the grinding wheel off and measured the run out on the 3" long arbor with a DTI, .0096" :oo:
I then took the arbor off and checked the grinder shaft, 0025", not so bad but annoying all the same.
At first I thought it was damaged by some numbnut bashing the arbors off with a hammer as no tool for removing the arbors from the tapered spindle was in the bits box, further inspection revealed that the bolt hole in the spindle is drilled and tapped on a slight angle and when the longer bolt used for the longer arbor is screwed in and the shaft turned the bolt head scribes a 1/2 circle in the air.
The bolt was pulling the long arbor on an angle, the shorter arbor seemed to go on better an had the same run out as the shaft.
I left it for a few weeks to think about. I had a TPG that I thought would do the trick but I had no wheel for it nor could I find one, it has a 12mm dia shaft.
I ended up getting a wheel with a 20mm hole and I made a flanged bush for it and a new 10 x 1.5 L/H nut.
Dressed the wheel by mounting the dresser on the bottom of the spindle housing.
Colored the shaft with blue texta and touched it until the blue disappeared, about .003"

shedhappens
29th Jul 2017, 05:46 PM
I needed more arbors, I made 2 L/H and 2 R/H and a nut for the long arbor. The long arbor has a R/H thread and never should have been mounted on the LHS. There's a new puller, a pin spanner was there but I needed something for undoing the nut when using cup wheels. And for tight nuts needed something for holding arbors in the vice.

shedhappens
29th Jul 2017, 06:16 PM
It had 1/2 a turn freeplay on the Y, both the screw and the nuts were badly worn so i made new ones, I didn't like the way the backlash nut was held so I made a retainng cap for it, still need to make a pin spanner for the backlash nut.

Here is a very short clip cutting the thread https://www.youtube.com/watch?v=9zHt3i7wDus I added that coz I know you all like vidz :D

cheers, shed

ps, 3/4" x 10 TPI ACME

shedhappens
7th Aug 2017, 07:29 PM
G/day all, here is a sneak peek at a tool that I am making.

The last owner of this machine didn't have this tool as he had been belting the chucks out of the powered workhead with a drift,:o surprisingly the spindle seems to to be in good nick.

The idea is to expand the end of the tool tightly in the spindle, holding one of the knurled flange's and turning the other will screw and pull a tube with a tapered end into the taper in the slotted tube.

I measured an ER40 collet roughly with a protractor and got 12 and a half deg so that is what I cut the taper to.

To complete this I need to make the internal tapered tube and also two shafts that can be screwed into this tube.
One of the shafts will be used to push the chucks off the spindle taper and the other shaft will be for operating the collets.

Material is 4140.

cheers, shed

shedhappens
23rd Aug 2017, 08:45 PM
G/day all, here is the rest of the parts.

The tube with the tapered end slides into the tool body first and is spun in on the thread until the taper just touches the tapered fingers.
If a chuck needs to be removed then the do dar with the shinny brass bit is screwed into the tapered tube and the whole shebang is inserted into spindle bore, turn the knurled knob (at left in picture) in a clockwise direction and nip up with the C spanners, this pulls the tapered tube in and forces the fingers to expand firmly onto the spindle bore.
Turn the hex and push the chuck out, no bashing and the set up of the work head should stay exactly where it was set up while changing chucks or collets

You might have seen the new shinny knurled bit, it just slides on and is a spacer ring to set the distance required when using the collet drawbar.

To use the collets remove the chuck pusher and screw the collet drawbar all the way in, stick the whole shebang back in the hole and tighten as before, now a collet can be screwed in from the other end until it just touches the taper in the spindle.
The thread on the end of the drawbar is 1/2 UNF and the thread on the collet is 2mm pitch, turn the hex in a clockwise direction to tighten the collet and by turning anti-clockwise it will push/release the collet out of the tapper......NO BASHING :D

While I was at it I knocked up a drawbar so I can use these 3 mt collets in the horizontal mill.

You know....... I think that I would rather self flagellate or bash my fingers with a hammer or maybe even commit self immolation than cut those internal Buttress threads.......

cheers, shed

LexD
23rd Aug 2017, 10:08 PM
Very nice work on all of those bits and pieces.

Anorak Bob
25th Aug 2017, 10:59 AM
Extremely neat Shed!:2tsup:

I do like the idea of being able to gently release an arbor from a bore without the use of a drift. Hercus included a threaded nose on their little No.O mill's dividing head 3M spindle, facilitating the extraction of some arbors. Strangely, the No.1 tool and cutter grinder's workhead spindle had a threaded nose but the threaded nose was deleted when the design of the workhead was later revised. I have the revised version. An extractor along the lines of yours would be a worthwhile project, well worth the effort to ensure that the head/s stay put.

Thank you.

Bob.

shedhappens
25th Aug 2017, 08:41 PM
Thanks for the compliments Techo and Bob, and others for the likes ect.

Yes Bob is was a good little project but not appreciated by all, I showed it to my mrs and she said " that's nice" and then started waffling about the clothes line and something about Camellias. :rolleyes:

If there is anything more you want to know about this let me know.

cheers, shed

Oldneweng
25th Aug 2017, 10:41 PM
Thanks for the compliments Techo and Bob, and others for the likes ect.

Yes Bob is was a good little project but not appreciated by all, I showed it to my mrs and she said " that's nice" and then started waffling about the clothes line and something about Camellias. :rolleyes:

If there is anything more you want to know about this let me know.

cheers, shed

What colour are the camellias? :D

Dean

KBs PensNmore
26th Aug 2017, 12:06 AM
When she said " that's nice", did she say it like Mrs Brown does? That's how my other half usually say's it to me!!!

Bryan
15th Sep 2017, 06:17 PM
Very tidy work there Shed. Would you mind telling me about your process for the arbors? Did you turn them all in one setting or flip them? I need to make some too. My spindle has male threads but otherwise they're quite similar. I have a procedure in mind but wonder if I'm over-complicating it.

shedhappens
16th Sep 2017, 04:45 PM
Very tidy work there Shed. Would you mind telling me about your process for the arbors? Did you turn them all in one setting or flip them? I need to make some too. My spindle has male threads but otherwise they're quite similar. I have a procedure in mind but wonder if I'm over-complicating it.

G/day Bryan, l made a lot of swarf making those arbours :D I cut them out of 65mm 4140 as that was the closest that l had to get the 52mm OD.
I cut the od then the 1 1/4" wheel mount dia. then the wheel thread, then put a drill through and bored nearly to the small diameter of the taper, bored for the puller and cut a small relief at the back of that bore for the end of the puller to sit flush against, then l cheated cutting the puller thread but don't tell anyone, ok...
l think it was a 12 tpi but because it was short in length and i was using a metric leadscrew lathe l cut a 1.25mm pitch and cut it from the back of the bore with the lathe in reverse. I trepanned the wheel relief in the flange with a parting tool.
Parted it off then did the same for the others.
To set up to cut the tapered bores i used a 10th dti to centre the arbour and as i only had about 12mm to grip on i also used the 10th dti on the flange where it had been parted off and used a small copper hammer to true the flange as even tho the chuck is pretty new it is not accurate enough (for me) to just push the flange against the jaws, tightened the chuck and rechecked/adjusted the run out, cut the counter bore and then cut and polished the taper.

I had set up one of the original arbours in the chuck and I used the little starrett back plunger to adjust the topslide, here is a pic (below) of the set up on a differant job, after i cut the first taper i polished it with wd40 and 400 wet n dry, then checked it on the grinder shaft with blue, i set an indicator onto the side of the topslide and gave it about a 002" movement one way and did another very light cut and polished and checked it again and good to go. Then i just bored and cut the tapers.

cheers, shed

edit.....the puller thread was 20 tpi, 25.4 / 20 = 1.27

Bryan
16th Sep 2017, 08:01 PM
Thanks a lot for the details. I'm trying to avoid the whole truing-in-two-planes-at-once thing because it's driven me nuts in the past. I have an idea that might solve the problem. Rather than waffle on here I might try it and post the results in a new thread.

shedhappens
14th Feb 2018, 06:29 PM
About time that I added a bit more to this thread.
Here is a cylinder that I have made for this grinder, I couldn't find tube the size that I required so I bored out a 400mm length of 4140.
I explained how I cut the threads on the chrome rod here http://metalworkforums.com/f65/t201060-threading-chrome-rod?highlight=threading+chrome+rod
I'm probably not happy about the mounting, I just couldn't fit a clevis type of mounting in there as the bearing surfaces would have been to narrow. the mounting really needs to be in the centreline of the cylinder, if this looks like it will wear the front rod bush prematurely then I will make a mounting for the front of the cylinder

If it leaks when I fire up the pump at least I will know the pump is working :wink:

shedhappens
14th Feb 2018, 07:26 PM
I dunno if this pump is going to work, I changed it from closed loop to open loop.
I wanted a variable flow pump so that I could adjust feed speeds, this is a hydro trans off a Murray ride on mower.
I won't need much flow or pressure and the pump is running at its lowest recommended RPM so I'm hoping it doesn't cavitate.
I have removed the motor and directed the oil flow out where the output shaft would normally be.
I have blocked the oil gallery that would normally reverse the motor and drilled some holes that will now be the inlet oil holes for the pump and removed and blocked the ball valves.

shedhappens
14th Feb 2018, 08:25 PM
More pics, poodah is crashing so I will keep this short

Anorak Bob
14th Feb 2018, 11:12 PM
More neat work Shed.:2tsup:

Any chance on expanding on the lapping of the cylinder bore?

I know next to nothing about hydraulics so at risk of sounding dozy, how is the stroke of the ram altered?

Bob.

PS I just viewed the last bunch of photos. Outstanding stuff Shed!!

shedhappens
15th Feb 2018, 03:40 PM
G'day Bob, I am no expert on hydraulics either, what I did know I have forgotten so now I only know enough
to be dangerous.
Lapping the cylinder, Bob I had a pretty rough hole to deal with after boring, first I gave it a linish with emery
on a rod, then I wore out a brake cyl hone (a cheap one) and at this stage the cylinder measured about .00014"
bigger from the centre to towards one end so I thought rather than persist with cheap hones I would see how
a lapping tool would perform.
My only experience with lapping comes from 25 - 30 yrs ago lapping m/cycle
big end brgs and mains, and my old man had me lapping spool valves at some stage.
So I found this chunk of aluminum, I think that my brother poured it some time ago, I'm guessing that it would consist of
20% milk bottle tops 30% fanta and 50% coke cans.
I made a lapping tool and used valve grinding paste, 400rpm, in out in out in out.
Lots of cleaning and measuring, small adjustments on the lapping tool as you want the paste to do the work
and the lapping tool will grab if you get too ambitious.
So with every adjustment when the tool is reinserted you need to be intently listening to the gear noise/ load
on the lathe and the feel of the pressure on the saddle handwheel, the lathe that l used for this is 7hp and l
felt at the time that l really should loosen off the belts to guard against grabbing. I tried a few mixtures with
the valve grinding paste, water, trefolex paste and liquid, rocol, in the end it was mixture of all of them.
The lap broke as l was nearly finished, it fell in half when l went for another adjustment, ha... l thought
that the old coke cans would have been better than that !
I spent 6 to 7 hrs lapping and it ended up within about .0006".

cheers, shed

Anorak Bob
15th Feb 2018, 04:28 PM
Thank you Shed for talking the time to explain the process.

Would you undertake the task again of boring and lapping or would you try to track down an existing cylinder that might suit? ( Mind you I have no idea of the cost of these things. )

Bob.

shedhappens
15th Feb 2018, 08:34 PM
Bob I would have preferred to just buy a cylinder, or modify one to suit, or buy the tube and go from there.
But at the time I could not find anything in the size that l needed, even the tube suppliers did not have stock the
size l required and said that it would be some months before they could get it.
I had a length of 40mm 4140 so l thought that l would have a crack at it and if l stuffed it up then no big deal either try again or wait to get the tube that l wanted.
Would I do it again? yup, if I couldn't get the tube I would, I don't mind a bit of a challenge but I think that a better boring bar and a suitable hone would have saved me many hrs of work and produced a better job.

cheers, shed

shedhappens
19th Feb 2018, 04:30 PM
I had this filter with a 3/4" unf thread................

shedhappens
3rd May 2018, 11:31 PM
Here are some work in progress pics and the bits for attaching the rod to the table.
I took about .030" off the underside of the table in an attempt at getting a flat surface for the mounting plate, things don't always go to plan though, tough as, l got the surface pretty flat with with a stone with no rock/movement in the mounting plate then sat it on some 620 loctite, nipped it up and tightened the following day.

So it had the maiden voyage today, it still has a bit of air in one side of the cylinder so it is a bit jumpy at a low feed rate, hopefully that will bleed out.
Here is a little vid of it for you guys, its just a rough set up to throw some sparks :D

https://www.youtube.com/watch?v=FjARIJxqaEo&feature=youtu.be

cheers, shed

Anorak Bob
4th May 2018, 09:24 AM
What a job! :2tsup: Fantastic work John, makes me wish I knew something about hydraulics.

A couple of non hydraulic questions. Are you using the Loctite 620 as a gap filling bed for the plate? And is there a reason for grinding with the wheel skewed?

Bob.

shedhappens
4th May 2018, 03:04 PM
Are you using the Loctite 620 as a gap filling bed for the plate?


G/day Bob, yes.
I couldn't get a good idea of the flatness with blue, no room to slide the mounting plate back and forth,
l could rock the plate slightly on the high spots and from this l could work out where they were.
l worked at them with a small norton stone, after l could feel no movement in the plate l measured
the remaining high spots by using an indicator on the 4 corners while trying to rock the mounting plate.
l got it sitting perfectly flat but it was obvious that it was a bit of a motorcross track down
there, so yes l wanted to spread the load over a larger surface area than a few high spots.
The surface looks worse in the picture than in reality, it felt smoother than a babys bum so
l am guessing that it was within .0005" - .001".
l used the 620 because l thought it would help me sleep better if l put it under there.



And is there a reason for grinding with the wheel skewed?

The chuck was in the way when the table was over to the right so l spun the head around for the wheel to clear
the chuck, to get full travel l need to use a collet fitted with a centre with a bolt hole and bolt in it to drive the dog,
I did say it was a rough set up :rolleyes:

shedhappens
31st Jul 2018, 01:37 PM
Hi all, I wanted to slow the spindle speed for use of some larger diameter wheels that I have, they are 8" and are for my out of action surface grinder but will work nicely on this at the correct speed and the VFD will also allow for faster speeds for smaller dia wheels without having to swap the belt to the higher ratio pulleys.
I will measure the speeds at different freq's and make a chart that will stay near the grinder.

The VFD's are from ebay and cost $119 ea delivered, 380 - 380 v

2nd VFD is for controlling the speed of the work head, I have not measured the RPM but it really whizzes around and I have had to balance the job and drive dog on a couple of jobs and that can chew up time better spent elsewhere.

The VFD cubby house is just made out of 20 and 25mm angle and few pieces of flat here and there, clad it with aluminum sheet, added a couple of fans and dividers/baffles to direct most of the air from the fans through and under the VFD's and the fan in the VFD's should draw the cool air and and expel it through the vents in the doors.
I fitted a couple of Kohler air filters to the fan inlets and I might have to put a roof over them but I think I will see how they go before adding another job to the list :rolleyes:

I dont know how hot they will get on a hot day when working so I will keep an eye (or fingers) on them and if they seem to to be getting hot I will check the air temp and if needed I will put in bigger fans, these fans are 80mm and don't seem to push much air but fingers crossed they will do the job.

I used twisted pair cable to the control switches as I found some in the shed, this apparently reduces interference from electromagnetic radiation, and I left a couple of pairs in there for possible future use.

cheers, shed

Anorak Bob
31st Jul 2018, 01:54 PM
Neat work Shed. :2tsup:

You and Bob L are making me nervous about the absence of forced ventilation for the pair of VFDs I have shoehorned into the cast iron pedestal on the Hercus T and C. I need to have a hard look at it.

BT

shedhappens
31st Jul 2018, 02:10 PM
Hi Bob, I have seen a melted one at a mates factory and I have also seen a melted one on this forum, I think that one may have been in a post by graziano? some time ago.
I would say that at the very least if you have a thermocouple put it in at the air outlet of the heat sink and see what temp you get, hot weather is your worst enemy here tho I reckon.

cheers, shed

Nrcollar
31st Jul 2018, 02:11 PM
Shed
Very nice work. It looks like it will be buttoned up soon. Great pics and progress.
Thanks for sharing
Nelson

simonl
2nd Aug 2018, 02:52 PM
That's bloody nice work Shed. I really like the air filters. My poor VFD's don't get anywhere near that level of luxury!

Cheers,

Simon

shedhappens
3rd Aug 2018, 07:09 PM
That's bloody nice work Shed. I really like the air filters. My poor VFD's don't get anywhere near that level of luxury!

Cheers,

Simon

Yeah....it sorta looks like over kill but dressing wheels is a messy job and they are in the firing line down there, I have a small dust extractor somewhere so one day I might even make some fittings for that.

cheers, shed