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Bought a Quorn, have som questions

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Thomas Staubo01/02/2017 17:06:01
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The clamping of the front bar to the base is much tighter, and needs much less force.

By the way, I will buy a 1" straight shank ER collet chuck to use in the work head. I'm not sure if ER20 or ER25 is best.

If there was room (i doubt it), I would go with ER32, as I have a full collet set in that size.

Edited By Thomas Staubo on 01/02/2017 17:12:39

Simon Williams 301/02/2017 22:29:29
654 forum posts
82 photos

Hello Thomas,

There IS room for an ER32 collet holder, because I've tried it. I had to grind a shoulder on the rear of the threaded portion of the holder (behind the nut) as this diameter fouled the detent knob which projects forward of the face of the Quorn toolholder.

This is the knob of the spring loaded peg, which acts as the detent for a dividing wheel located on the rear of the toolholder. It's located in the toolholder casting just below the one inch bore where the collets were designed to fit.

But it was no problem to do this, I just put a handle on the back of the ER 32 holder - on the one inch portion sticking out of the toolholder and held it up to the grinding wheel until I'd let out enough sparks to make the ER32 holder fit snugly against the tool holder where it belongs.

I don't know of any real advantage of the ER32 size over the smaller one, as either will take a 16 mm endmill to sharpen it. But the Quorn that I bought did not have the tool holder collets included, so I thought buying something to use the ER collets was an easy answer.

I also changed the original 0 - 360 calibrated dial for one which was calibrated 4 times +/-45 deg, as I only use it to sharpen end mill and slot drills with either 4 or 2 flutes.  I don't bother with the detent idea for this, it's quicker to index the cutter being sharpened on my 45 deg scale.  Oh, and I've abandoned the pretty but ineffective threaded collet thing that clamps onto the outside of the one inch tool holder, in favour of a simple split clamp with a tangential cap screw.

HTH, if you would like to see pictures I can do that but it's cold and dark out there just now!

Best rgds Simon

Edited By Simon Williams 3 on 01/02/2017 22:41:51

Edited By Simon Williams 3 on 01/02/2017 22:48:42

Martin Kyte02/02/2017 09:09:09
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2751 forum posts
48 photos

I use an ER16 on mine which has the advantage of not projecting so far forwards. Someone has already commented that the Quorn is not good at mass metal removal (well it is a cutter grinder after all) it's proper function is restoring sharp edges not really rough shaping lathe tools. It is more convenient to have the edge of the tool somewhere near the centre of the rotating base as you find you need to make less adjustments when setting your angles. One thing I did do is fit a small perspex block angled like a prism that fits into the lug on the tilting brcket flush with the scale on the rotating base. It carries the fiducial line on the inside which enables accurate setting of the rotating base when looking from the side. When you wish to change the angle with a half ground tool already in the work head you don't want to remove the work head to see the scale setting and it's difficult to see under everything.

Sorry for the muddled explanation it would be better if the machine was in front of me but I'm working from memory.

regards Martin

Thomas Staubo02/02/2017 10:17:34
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54 forum posts
Posted by Martin Kyte on 02/02/2017 09:09:09:

One thing I did do is fit a small perspex block angled like a prism that fits into the lug on the tilting brcket flush with the scale on the rotating base. It carries the fiducial line on the inside which enables accurate setting of the rotating base when looking from the side. When you wish to change the angle with a half ground tool already in the work head you don't want to remove the work head to see the scale setting and it's difficult to see under everything.

Sorry for the muddled explanation it would be better if the machine was in front of me but I'm working from memory.

regards Martin

I would be great to see a photo of this, if it's possible.

I see that's it's near impossible to see the scale setting, when the work head is mounted.

Thomas Staubo02/02/2017 13:04:17
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54 forum posts
Posted by Simon Williams 3 on 01/02/2017 22:29:29snipped a bit)

Hello Thomas,

There IS room for an ER32 collet holder, because I've tried it. I had to grind a shoulder on the rear of the threaded portion of the holder (behind the nut) as this diameter fouled the detent knob which projects forward of the face of the Quorn toolholder.

I don't know of any real advantage of the ER32 size over the smaller one, as either will take a 16 mm endmill to sharpen it. But the Quorn that I bought did not have the tool holder collets included, so I thought buying something to use the ER collets was an easy answer.

HTH, if you would like to see pictures I can do that but it's cold and dark out there just now!

Best rgds Simon

Thanks a bunch Simon!

I remembered that I have some ER25 collets in the most used sizes, so I will order a 1" shank ER25 holder. I may have to grind/turn away a bit if it's in the way of the detent knob, as you say.

At the moment I only have one mandrel, with MT2 taper and Myford threaded spindle nose. I'm not sure what the threaded spindle nose is good for?

Simon Williams 302/02/2017 17:02:40
654 forum posts
82 photos
Posted by Thomas Staubo on 02/02/2017 13:04

I remembered that I have some ER25 collets in the most used sizes, so I will order a 1" shank ER25 holder. I may have to grind/turn away a bit if it's in the way of the detent knob, as you say.

At the moment I only have one mandrel, with MT2 taper and Myford threaded spindle nose. I'm not sure what the threaded spindle nose is good for?

Mine came with a MT2 socket with a 1 inch parallel OD, I've never used it, though that's what gave me.the idea of buying a ER collet with a parallel back. As for the nose thread, I wonder if this was to use the old style Myford collets which slid up the spindle bore and used a front closer nut to push the collet up the morse taper.

Rgd Simon

Edited By Simon Williams 3 on 02/02/2017 17:03:29

Martin Kyte03/02/2017 09:01:01
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2751 forum posts
48 photos

Hi Thomas

There are a couple of pics in my album of the scale modification.

regards Martin

Thomas Staubo03/02/2017 10:04:17
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54 forum posts

Aha! I see what you mean now.

My thought is that there should be an additional fiducial mark 90° to the left of the existing one.

Thomas Staubo07/02/2017 08:20:25
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54 forum posts

I was wondering what this lug on the casting was for:

According to the drawings, there should be a (5/16"?) through hole here. The book doesn't mention it afaik.

I have studied a lot of pictures of other Quorns on the web, and some has a hole here and others don't.

Thomas Staubo07/02/2017 08:44:57
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54 forum posts

After studying the Quorn, I see that the person that built this has made an alteration to the mandrel clamp in the work head. The mandrels should have a staright 1" shank, with a threaded clamping ring.

But instead the only mandrel I have are reduced at the rear, to 15/16" and itself threaded.

Instead the clamping ring should be threaded. This is the drawing showing how it should be:

I think I have to redo this, as my plan of using a 1" straight shank ER collet chuck can't be done, because the hole in the index ring is too small!

Both a new clamping ring, and an index ring therefore have to be remade.

John P07/02/2017 09:02:57
406 forum posts
257 photos

Posted by Thomas Staubo 07/02/2017 08:20:25
I was wondering what this lug on the casting was for:

Hi Thomas ,the lug on that casting is a location to enable the
tooth rest bars shown on page 21 in the Quorn book to be fitted.

I have used this for the setup shown in the photo .The axis of the
rotating base and workhead spindles are aligned using the half pins,
using the bars and the tailstock casting the position can be maintained
when the toolholder is repositioned.
A full article was published in MEW 215 and 216 Grinding radiused edged milling cutters .
Some additional photo's can be seen in album Quorn and cnc cutter grinder.

John


quorn  radius.jpg

Martin Kyte07/02/2017 09:44:19
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2751 forum posts
48 photos

Ah that's useful to know. I must finish my tailstock.

The bar on the work head, as has kind of been mentioned is good as a handle when radiusing tools.

regards Martin

Thomas Staubo07/02/2017 13:43:47
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54 forum posts
Posted by John Pace on 07/02/2017 09:02:57:

quorn  radius.jpg

Aha! That way you can slide the workhead to and fro, and take it off, without altering any angles.

Thanks!

In your picture, it seems you have two knurled rings on the index ring. Or is perhaps one of them a (very large) clamping nut?

John P08/02/2017 10:56:30
406 forum posts
257 photos


Posted by

Thomas Staubo 07/02/2017 13:43:47

 

"In your picture, it seems you have two knurled rings on the index ring.
Or is perhaps one of them a (very large) clamping nut?"

The index ring on my machine is made in several parts and has a
resetable dial and is constructed in a similar way to the index ring
on the front bar fig 9 on page 19 of Quorn book.
As can be seen in the photo the division rings are removable,the
two rings that i have cover most of the required numbers.
I over bored the casting to about 1 1/8 inch to fit a larger spindle,
the larger fixing collet is tightened using the pin spanner.

John
 

quorn index dial.jpg

Edited By John Pace on 08/02/2017 10:57:07

Thomas Staubo13/02/2017 08:07:16
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54 forum posts

I'm sorry John Pace, I forgot to reply and thank you for your photo and explanation.

You really thought it out when you made it.

It seems like you have 24 and 30 divisions. The 30 wheel must be for dividing into 5, 10, 15 and 30. Is that for special cutters, maybe like dovetail cutters?

John P13/02/2017 10:06:45
406 forum posts
257 photos

Posted by

Thomas Staubo 13/02/2017 08:07:16

It seems like you have 24 and 30 divisions. The 30 wheel must be for dividing into 5, 10, 15 and 30. Is that for special cutters, maybe like dovetail cutters?

It is just useful to have the facility to be able to divide these numbers.
I used the 24 division ring when making this dovetail cutter from some
scrap 1/8 inch carbide shanks.

John

shaper 3.jpg

shaper 4.jpg

Neil Wyatt13/02/2017 10:34:19
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19032 forum posts
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80 articles

Wow John, your cunning is remarkable!

ega09/06/2017 11:31:19
2538 forum posts
201 photos
Posted by Thomas Staubo on 07/02/2017 08:20:25:

I was wondering what this lug on the casting was for:

According to the drawings, there should be a (5/16"?) through hole here. The book doesn't mention it afaik.

I have studied a lot of pictures of other Quorns on the web, and some has a hole here and others don't.

I am grateful to Thomas Staubo for asking this question and to John Pace for answering it (and for his excellent article in MEW 215 and 216). The following is unlikely to be of interest to other than Quorn users.

When I built my own machine many years ago I was mystified by the drawing of this part (item 510), didn't put the hole in and have never missed it up till now, although I have used the tooth rest with its support attached to the column as normal. Departing from DHC's drawing was a bold step and I think I was influenced by the fact that the hole does not seem from his photos to be present in his own machine.

Now that John Pace has shown how useful the hole can be, I have put it in and in doing so have noticed that the lowest hole as drawn is the other way round from that in the photo and, indeed, from my own machine and DHC's!

Sadly, DHC is not here to help with these points but, on a different issue, those whose tilting brackets tend to slip should take note of the modification he outlined in ME of 5 September 1986.

 

Edited By ega on 09/06/2017 11:33:12

Hopper09/06/2017 14:31:09
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6393 forum posts
334 photos

That's an excellent pile for the price you paid. Well done indeed!

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