Model Engineers’ Workshop – July 2019

66 http://www.model-engineer.co.uk Model Engineers’ Workshop

90

20

60

22

5

7

12

30° 50

90

6

88

90

25

25x3

10

4 holes M6

3 holes Ø4.3 csk.

2 holes

Ø4.3 csk.

3 holes Ø6.3 csk.

Multi Mounting Plate End Stop

File to clear

12mm drill

3 holes tap M4

Clearance for gib

nuts on grinder

M6

4

5

Taming the ‘Universal’

Tool and Cutter Grinder

I

always planned to make some form

of tool grinder. There are three types

available for the model engineer to

construct, Quorn, Stent and Woden but

will take a lot of time to. All will do a good

job and while all have their deficiencies,

owners will champion them. The Quorn

is the cheapest at about $400 which

now only seems to be available from

the USA. For the stent, a set of castings

casting will now cost in the order of

£500. The Woden, a modification of the

one designed and used by the late great

George Thomas, costing about £450 if

you include all the accessories. Finally,

there is the Chinese “Universal tool and

cutter grinder”. A Google search will

show many examples of these, and two

examples are sold by RDG and Chronos,

(there will be others). These range in price

from £500 to £900, but there shouldn’t

be any tool making involved with one of

these (or so I thought). At an auto jumble,

I discovered a very cheap version of this

machine with an initial asking price under

£300 and after a lot of bartering, a deal

was struck, photo 1.

The machine proved to be very

capable for lathe tools, but “Universal”

as purchased it is certainly not. They

are originally designed for the grinding

of single point engraving tools. Many

forums state that this type of machine

is useless for multipoint cutters such as

end mills, slitting saws and four-facet drill

grinding so should be avoided. I intend

to show you that this is not the case,

and a series of very simple additions and

modification to the machine will enable

all of these cutters to be sharpened with

ease. Another advantage is that most

of the tool setting can be done off the

machine with the employment of simple

setting jigs.

On getting the machine home,

the reason for the low price became

obvious. A number of the parts had

very poor standards of fit, but after a

bit of work which I won’t bore you with,

these problems were soon solved. This

transformed the machine, but it still

wasn’t “universal”. Incidentally, the

machines seen at exhibitions by the firms

indicated above have a quality which

significant order of magnitude better

than mine, and I have viewed them with

sadness because in comparison, mine was

rather cheap and poor (not now), so don’t

be put off by my problems.

The machine as supplied has a good

range of work heads:

1) Universal head with built in indexing

and a resettable degree scale

2) End mill grinding attachment with

a top mounted tool rest and a long

Graham Sadler modifi es an engraving cutter grinder to be more versatile.

1

Fig.1

The grinder showing some of the new gear.