Author Topic: 626 mill riser block  (Read 10737 times)

Offline John Rudd

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626 mill riser block
« on: November 10, 2016, 11:49:16 AM »
The 6" round bar arrived today for the riser upgrade on my mill...... :dremel:

It is some weight I can tell you!

Hopefully I can fit it in the lathe but how I'm going to hold it is yet to be decided.....! :coffee:

Meanwhile here's a picture of the lump! :clap:

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Offline John Rudd

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Re: 626 mill riser block
« Reply #1 on: November 10, 2016, 11:51:35 AM »
The sawn face looks a good starting point for a datum....I s'pose I could put it on the mill table and fly cut the other side to ensure that is parallel, or I could drill and tap it and mount it on a face plate in the lathe......

If you were doing this what would your choice be?
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Offline RobWilson

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Re: 626 mill riser block
« Reply #2 on: November 10, 2016, 11:53:30 AM »
 :clap: :clap:  Thats a canny wee project John  :dremel: 


Quote
If you were doing this what would your choice be?

I would true it up in the 4 jaw  :dremel:


Rob

Offline John Rudd

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Re: 626 mill riser block
« Reply #3 on: November 12, 2016, 10:31:04 AM »
Well had to go to Gateshead this weekend to help out with the granbairns.....so no further forward...

However it has given me some thinking time about how I should machine the block.... :scratch:

Looking at my 4j chuck, its max reach is around 6"....so the bar will probably just fit....so I'm thnking of buying a bigger chuck ....this one.. 282230982967 But I'll also need a backplate to match...

Onwards and upwards.... :dremel:
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Offline John Stevenson

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Re: 626 mill riser block
« Reply #4 on: November 12, 2016, 11:43:58 AM »
John as you say they are big lumps and in a chuck, not holding on by much.

First one I did I did it in a big 3 jaw but still had it come loose, loose, not fly out, a couple of times.
Did all the machining and then drilled the 3 holes and the penny dropped.

Next one I did I faced both ends carefully then marked out and drilled from both ends 3 holes in each at 8.5mm and tapped them M10.

Fastened it on the face plate by the M10 screws with 4 dogs on the outside to act as "jaws" Never moved and then did all the machining at a far higher speed than the first one.
The M10's get opened out to M12 clearance or tapped M12 depending on your design.
John Stevenson

Offline RobWilson

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Re: 626 mill riser block
« Reply #5 on: November 12, 2016, 12:30:17 PM »
 :scratch:  just use the tail stock centre and centre drill each end of the work  ! it cant come loose or out with a centre holding the un-chucked  end .  :thumbup:


Rob




 

Offline John Stevenson

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Re: 626 mill riser block
« Reply #6 on: November 12, 2016, 01:23:33 PM »
:scratch:  just use the tail stock centre and centre drill each end of the work  ! it cant come loose or out with a centre holding the un-chucked  end .  :thumbup:


Rob

Hard to bore a hole down the centre with the tailstock in the way.  :scratch:
John Stevenson

Offline John Rudd

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Re: 626 mill riser block
« Reply #7 on: November 12, 2016, 01:54:09 PM »
I was thinking of facing both ends, centre drilling and then centre on the mill and doing any boring in there....ah, but there's a spigot to machine. That can be machined in the lathe with tailstock support....

So thats my plan, unless anyone has any better ideas/suggestions?

 
Oooops, just read John's previous post re faceplate mounting....yup that was summat else to consider...thanks for the idea. :thumbup: That sounds like a better way and cheaper than having to buy another chuck/backplate...
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Offline RobWilson

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Re: 626 mill riser block
« Reply #8 on: November 12, 2016, 03:04:01 PM »
Why would a 626 mill require a bored out riser, is that not just creating  un-necessary work   :scratch: 


Rob

Offline John Stevenson

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Re: 626 mill riser block
« Reply #9 on: November 12, 2016, 03:08:39 PM »
Thick walled tube is better than solid any day of the week, Young's modulus and at only 6" diameter it helps to have all the stiffness you can get when you are sticking it another 6" into fresh air.
John Stevenson

Offline John Rudd

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Re: 626 mill riser block
« Reply #10 on: November 12, 2016, 03:12:04 PM »
From the drawing I've seen on the yahoo groups website, it looks like it just has a recess and spigot...so looks like its fabbed from solid, ergo I'd see no reason to poke a hole in the middle unnecessarily....besides, I dont have a drill long enough to go right through... :Doh:
Ahem,
John posted while I was typing....
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Offline John Stevenson

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Re: 626 mill riser block
« Reply #11 on: November 12, 2016, 03:59:37 PM »
I have probably done about 6 of these now from various suppliers and I don't think any two have had the same spigot diameters as each other.
Now some were very early, possibly Taiwanese machines but a big difference on some. might pay you to take a quick measure first.

Just for interest, the Bridgy which is a far heaver built machine, [ did I post that ? ] is able to lift itself and fit the riser block.



This is a machine that has the slotting head on the back as well, my idea was to try it and if it was struggling, to ease the rear with a porta power ram and extension byt just raising the bed by hand , it managed fine.

John Stevenson

Offline John Stevenson

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Re: 626 mill riser block
« Reply #12 on: November 12, 2016, 04:01:09 PM »
Damn, wondered what had happened to that red shirt, no wonder I couldn't find it...........................
John Stevenson

Offline awemawson

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Re: 626 mill riser block
« Reply #13 on: November 12, 2016, 07:26:17 PM »
Nice riser John - WHERE did that come from  :lol:
Andrew Mawson
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Offline malbenbut

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Re: 626 mill riser block
« Reply #14 on: November 13, 2016, 06:38:13 AM »
I have about 10ft off 5.5/8"x 3/8" wall thickness tubing  that may be suitable for riser block.
I was going to use for a chimney for my stove.
Open to offers.
In Northumberland

MBB

Offline awemawson

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Re: 626 mill riser block
« Reply #15 on: November 13, 2016, 08:40:16 AM »
And I've got an 'offcut' 5.5 metres long of 5.5" x 5 mm wall tube left over from making the new roller for my flail mower that might perform service as a riser if anyone 'down south' needs a slice cutting off.
Andrew Mawson
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Offline John Rudd

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Re: 626 mill riser block
« Reply #16 on: November 15, 2016, 11:03:24 AM »
So now back home and in the shop.....

I swapped out the 3 jaw for the 4 jaw indi chuck on my lathe....

The 160 mm chuck is more than man enough for holding this big piece of round bar... :thumbup:

So tried clocking it up, the outer surface is a bit rough, I managed to get it within 5 thou at the free end.....but the  chuck end....ooh man its well out of true....

So do I leave as is and true up the diameter as far as I can get to the chuck end or should I clock it at the chuck end and then machine the diameter?

Never done this before so any advice appreciated.... :bow: :bow:
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Offline philf

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Re: 626 mill riser block
« Reply #17 on: November 15, 2016, 11:28:11 AM »
So now back home and in the shop.....

I swapped out the 3 jaw for the 4 jaw indi chuck on my lathe....

The 160 mm chuck is more than man enough for holding this big piece of round bar... :thumbup:

So tried clocking it up, the outer surface is a bit rough, I managed to get it within 5 thou at the free end.....but the  chuck end....ooh man its well out of true....

So do I leave as is and true up the diameter as far as I can get to the chuck end or should I clock it at the chuck end and then machine the diameter?

Never done this before so any advice appreciated.... :bow: :bow:

John,

Unless you've lots of material to spare on the diameter I'd get the bar fairly parallel to the axis of your lathe and then carefully face  off and take a minimal skim off the od just enough to clean up and clear the depth of the chuck jaws. I'd then turn it end over end so the nicely faced off end fits snugly against the chuck and the chuck jaws will have a nice perpendicular surface to clamp on. If your piece of bar is sawn it's quite possible the ends may be quite a bit off-square.

Phil.
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Offline awemawson

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Re: 626 mill riser block
« Reply #18 on: November 15, 2016, 12:13:02 PM »
John, I know that you say your chuck is more than man enough to hold it, but I'd be nervous with that amount of overhang with such a weight  :bugeye:

I reckon your earlier idea of tapping and bolting from the rear of a face plate would be safer - it only needs a tiny dig in with your boring operation to totally spoil your day  :scratch:
Andrew Mawson
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Offline Pete W.

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Re: 626 mill riser block
« Reply #19 on: November 15, 2016, 12:37:59 PM »
If it was me, I'd choose the squarest end and carefully explore for the centre, say with a centre square.  Having centre-popped it, I'd chock the piece on the table of the drill-press so that the flanks were at right angles to the table surface.  If you've got a big enough angle-plate, stand it on end on the drill-press table and clamp the piece into its 'vee' with a big G-clamp.  Centre drill to enlarge the centre-pop.  Then I'd transfer the piece to the lathe with the other end in the chuck and the tail-stock supporting the centred end, using a half-centre if you have one.  Hopefully, the end in the chuck will be square enough for the chuck jaws to get a good grip - even if the piece only touches the face of the chuck in one place.  Face off, leaving the smallest possible spigot in the middle, hopefully small enough to go through the hole in the chuck or face-plate.  Marking-blue the end and mark out the holes to attach to the face-plate, remove from the lathe and drill and tap the holes.  (If you're feeling really fussy, file off the spigot first.)  Transfer to the face-plate and proceed according to John S' method.  Having got the piece securely mounted on the face-plate, there might be some merit in facing off the now outer end and putting in a set of tapped holes in that end too.
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Offline John Rudd

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Re: 626 mill riser block
« Reply #20 on: November 15, 2016, 12:39:23 PM »
Andrew,
I share your concerns too....its a bit daunting with around 20kg of metal spinning around even at 100rpm.....
The backplate idea is a non-starter.... The holes in my backplate are such that it wont accomodate bolts 120 degrees apart.....

So further thinking required in an approach.....
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Offline Pete W.

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Re: 626 mill riser block
« Reply #21 on: November 15, 2016, 12:42:50 PM »
Andrew,
I share your concerns too....its a bit daunting with around 20kg of metal spinning around even at 100rpm.....
The backplate idea is a non-starter.... The holes in my backplate are such that it wont accomodate bolts 120 degrees apart.....

So further thinking required in an approach.....

Couldn't you make an adaptor plate? 
Best regards,

Pete W.

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Offline awemawson

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Re: 626 mill riser block
« Reply #22 on: November 15, 2016, 12:56:13 PM »
Dare I suggest that you drill your face plate  :scratch:
Andrew Mawson
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Offline John Rudd

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Re: 626 mill riser block
« Reply #23 on: November 15, 2016, 01:13:06 PM »
Food for thought guys....thanks... :thumbup:
I've knocked off for the nite...back to work  tomorrow..so more shop time over the coming days.. :lol:
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Offline Spurry

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Re: 626 mill riser block
« Reply #24 on: November 15, 2016, 02:36:50 PM »
John
Of all things you have to do with that chunk, the o/d is the least important. When I made one for my little machine, I just got it running sort-of true by eye, then centre drilled the outer end. Held it in place with a running centre, then faced off the outer end as much as possible, with a little skim up the outside to sit in the jaws.
Flip it over in the chuck, and repeat.
On the second facing op, the piece should hopefully be sitting at the rear of the jaws, so depending how much out, the second facing cut is, depends whether you risk removing the supporting centre.
Stick it in the mill, drill/tap to correct pcd.
As you cannot fit it on the faceplate directly, go with the adapter plate suggestion.
This should get you in the ball-park of two parallel faces.....the world is then your oyster.  :wave:
Pete