Background
I have been the proud owner of a Worden Tool and Cutter Grinder, Ref.1 for some time now and, as with most tools we use, various things are done over time to make for easier use or to provide added facility.
 
What follows is by no means meant as a criticism of the tool, its accessories or of its design, but is a description of what I have done to satisfy my personal requirements. These findings are passed on for the information of other users who might find some aspects of interest, or worthy of consideration for their own use.
 
Dust control
 
One of the first considerations was to address the dust problem caused by the motor fan blowing air forward onto the table parts, photo 1.
 
 
 
 
This wheel guard was described in Model Engineers’ Workshop Issue 104. Although successful, a slight modification has since been made to facilitate my frequent changes of grinding wheels, photo 2.
 
 
 
 
This was merely attaching the front cover only and allowing the now open back to rotate about a hardboard disc pressed onto the boss at the front of the motor, photos 3 & 4.
 
This allows the guard to be simply pulled off to gain access to the wheel, or to replace it with an alternative, shorter guard for use with a disc type of wheel. It is easily rotated to either side of the wheel and the rear disc effectively stops any undesirable airflow.
 
Table control
 
The next modification was to provide controlled lateral movement of the table with a feed screw. This was described in Model Engineers’ Workshop Issue 122, photo 5. Although Hemingway Kits do provide such a screw adaptation, I preferred to use a quicker method of positioning the table to either side of the wheel and for the initial setting. As already stated, this method provides 4in. of instant movement and 4in. of controlled movement.
 
Accessories
 
I have made some of the supplied accessories for the grinder, namely the four-facet drill jig and the slitting saw jig, Ref. 1. It was whilst seeking advice on making these jigs from Kirk Burwell of Hemingway Kits that we discussed why it was necessary to make another work slide to accommodate the four-facet jig. He suggested that as I had all the bits in front of me, I could explore the possibility of using only one work slide for all of the accessories.
 
Common work slide
 

 
The original work slide uses a 40 tpi screw against an inserted button to push the tool holder forward, photo 6, whereas the drill jig uses a captive 40 tpi feed screw working in a nut in the jig base, photo 7. As can be seen in the photos, there is a considerable difference in the location of the feed screw bearing block on these work slides.
 
The conclusion was to adopt the feed screw held in a bearing block as in the drill jig. This replaces the threaded block of the original work slide, and also to replace the button in the tool holder with an adapter to hold the nut for the feed screw, photo 8. Although ideally turning the knob clockwise should increase the cut, the thread would have had to be made left handed. In practise, turning the ‘wrong’ way isn’t really a problem as only tiny increments are used during grinding. Is this any different from the subtractive cuts put on when boring in the lathe; which we all do without any problem ?
 
It was also decided to incorporate a Zero adjustable scale on the feed screw knob, photo 9. The numbers on the collar were stamped in the appropriate direction. It will be noted that due to the design of the various accessories, the distance from the bearing block varies. This variation is accommodated by making the respective adapters of a length to suit.
 
Once made and fitted, it is only necessary to release the grub screw in the adapter to allow the accessory to be slid off the feed nut which remains in place on the feed screw, and slide the next accessory onto the nut, locking it with the grub screw. The slide locking bolt fitted to the left-hand guide of the drill jig slide was also transferred to the work slide, as the normal lock screw strap has to be removed to fit some of the attachments. In fact this could now be left off altogether. The feed screw locking method was retained.
 
Having passed my conclusions on to Kirk, he very kindly adopted my modification and produced a CAD drawing for an adapter kit, which he intends to supply (HK 1300W).
 
The slitting saw jig
 
The slitting saw jig, Figs. 1 to 7 used a piece of 1in. x 1/4in. flat stock to provide the tenon guide in the Work Slide. It was found on completion that with the work table horizontal and a saw blade fitted, the teeth were a significant distance below the centreline of the grinding wheel.
 
 
This was easily overcome by replacing the tenon with a piece of 1in. square material to bring the saw to centre height, photo 10. The tapped holes for the blade-retaining stud were replaced with a slot and a rebate to hold an M6 hex bolt captive, Fig 1.
 
 
 


This allows the teeth to have the closest support for various blade diameters, ranging from 3/4in. to 4in., photos 11-13.
 
Drill Grinding Jig
 
When I started using the four-facet drill grinding jig, it was found that the table had to be pulled right forward and there was a conflict with the drill clamping screw and the grinding wheel, photo 14.
 
 
 
 
Reducing the height of the clamp screw bracket and moving the V block back level with its support plate resolved this, photo 15. Although reducing the effective length of the drill clamping arrangement, this has not detracted from its use with large drills. I did however find the indexing collars a bit tedious as when rotating the drill for the next lip, any slight movement of the collar caused one of the screws to loosen and the length setting was lost. The insertion of a small steel ball between the lock screw and the V pad with some firm tightening cured this tendency.
 
Alternative Drill Jig
 

 

 
Although the jig is effective for the intended purpose, it is limited to a single angle and will not cope with short drills or centre drills. While wondering what to do with the triangular off-cut from the drill jig body, I came up with a jig adjustable to any angle from 0 to 90deg., photo 16, that will hold and index anything from a centre drill, photo 17 to a 1/2in. drill, photo 18, Figs 8 to 20.
 
Following the advice of ‘Blind Pugh’ in his excellent articles on Tool-Room Topics, I have since produced a set of both countersink and flat bottom drills with this jig for use with the Allen screws I commonly use, photo 19.
 
 
 
Vertical Slide
 
 

 
It was felt that there was a need for some form of controlled height adjustment to ease some grinding operations, and a vertical slide type of attachment was made, which was also quickly interchangeable, photo 20, Figs 21 to 41 and vertical slide GA.
 
The original Spindle had a 1/2in. bore to take various split adapters and drill chucks on suitable arbors, photo 21. This has now been supplemented with a spindle bored to take the Collets from my Cowells lathe, photos 22 & 23.
 
 
 


The controlled and full free rotation of the spindle, allows the grinding of such items as end mill side teeth, a new lead on a broken/worn tap, accurate punch and scriber points or any item requiring accurate rotation against the grinding wheel.

 

 

Vertical slide parts list

 

Fig 21

Base slide

BMS - 1in. x 1/4in

Fig 22

Feed screw bearing block

BMS - 1in. x 3/4in

Fig 23

Slide base

BMS – 1 1/2in. x 3/4in

Fig 24

Feedscrew bearing plate

BMS – 1 1/2in. x 1/4in

Fig 25

Feed screw

FCMS – 1/4in. diameter

Fig 26

Feed knob

Brass – 1in. diameter

Fig 27

Slide block

BMS – 1 1/2in. x 1 1/4in

Fig 28

Spindle

PGMS – 5/8in. diameter

Fig 29

Spindle knob

Brass 1in. diameter

Fig 30

Slide lock screw

Brass 1/2in. diameter

Fig 31

Tooth rest lock screw

Brass 1/2in. diameter

Fig 32

Spindle lock screw

Brass 1/2in. diameter

Fig 33

Cam plate lock screw

Brass 1/2in. diameter

Fig 34

Cam plate

BMS 1in. x 1/8in.

Fig 35

Tooth rest block

BMS – 1/2in. square

Fig 36

Tooth rest block spindle

FCMS – 5/16in. diameter

Fig 37

Tooth rest spindle

FCMS – 5/16in. diameter

Fig 38

Tooth rest

Hacksaw blade

Fig 39

Index ring

FCMS – 1in. diameter

Fig 40

Cam follower

FCMS – 1in. diameter

Fig 41

Cam follower

FCMS – 1in. diameter

Second Lathe Tool Holder
 
When making or sharpening the ends of lathe tools I found that when the Work Slide was set at 90deg. to the wheel, there was no means of applying a controlled in-feed to the tool bit. This has been resolved with a new Tool Holder with the slot extending along both sides to allow the cut to be applied with the feed screw, photo 24.
 
 
Radius Table
 
In order to grind radii of a known dimension on the end of lathe tools, I produced an auxiliary semi circular table to fit onto the Work Slide, photo 25. In use the table is brought up to the grinding wheel and the feed collar zeroed. The table is then withdrawn by the required radius with the feed screw and the tool mounted to just touch the wheel. When grinding is started, the tool holder is moved back and forth following the curve of the table.
 
 
 
The radius at the point of contact with tool to wheel remains constant and further cut is applied with the screw bearing on the rear of the tool, until the amount of radius required is formed on the end of the tool. This sounds fiddly, but in practice accurate radii can be imparted onto form tools very quickly. Figs 42 to 53 and radius table GA.
 

 

Radius table parts list

 

Fig 42

Slide Base

BMS - 1in. x 1/4in.

Fig 43

Feed screw bearing

BMS -1in. x 3/4in.

Fig 44

Table pillar

FCMS – 1in. diameter

Fig 45

Table

3mm Sheet - 3in. x 1 1/2in.

Fig 46

Table guide

BMS - 1 1/2in. x 3/4in,

Fig 47

Tool holder

BMS - angle 1in. x 1/8in.

Fig 48

Tool clamp

BMS - 1/2in. x 1/4in.

Fig 49

Feed nut

FCMS - 1/2in. diameter

Fig 50

Clamp screw

FCMS - 3/8in. diameter

Fig 51

Feed screw

FCMS - 3/8in. diameter

Fig 52

Tool holder clamp

FCMS - 1/2in. diameter

Fig 53

Clamp handle

FCMS - 1/8in. diameter

 
4 facet Drill Grinding Jig HK 1310

Slitting Saw Grinding Attachment HK 1306

The above items are available from Hemingway kits.