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Hemingway Dynamic Toolpost Grinder

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Nick Hughes10/01/2019 19:49:10
225 forum posts
132 photos

I've had this kit for about 9 months and finally made a start on Jan 1st 2019.

First off the outer cover, clamped down lightly on 3 blocks, to machine the bosses.


After machining the bosses, the 3 blocks are clamped to the machine table and then the inverted cover stuck on to them with superglue


The joint face was then machined down to the drawing dimension, using 0.5mm/0.020" cuts and some breath holding


The inner cover was machined in a similar way, but no need for any superglue this time on the second face




As most of the holes in the inner cover are dimensioned using Polar Coordinates, I used the DRO functions for these and again to mill the radius slot.

This meant that (even though I have both a CNC mill and a 10" Rotary table for this manual mill) only the one setup was required.


More to come!





Edited By Nick Hughes on 10/01/2019 19:51:08

Neil Wyatt11/01/2019 12:54:16
17970 forum posts
709 photos
77 articles


Mark Gould 111/01/2019 19:45:42
217 forum posts
120 photos

Progress looks good so far Nick, keep 'em coming

Nick Hughes15/01/2019 10:42:47
225 forum posts
132 photos

Last Saturday mornings initial hand work:-

Fettled the Inner Cover cast appeture (this is slightly out of position, but not enough to cause a problem). The two 3.2mm drills, are just acting as temporary aliignment dowels between the two covers and will be replaced once the covers are painted,

20190115_100909 (2).jpg

Then the Outer Cover (Removed the Logo, to make painting easier),

20190115_100844 (2).jpg

Followed by dressing the assembled covers,


There's a bit more work to do and some dinks to fill before painting. This will be done when all the remaining castings are machined.and finished to the same level.

Edited By Nick Hughes on 15/01/2019 11:10:35

Nick Hughes21/01/2019 17:35:34
225 forum posts
132 photos

Started on the Spindle Housing this afternoon.

Only had enough time to rough bore though:-



Nick Hughes22/01/2019 17:47:57
225 forum posts
132 photos

Today was finish bore the two bearing bores (28mm & 32mm Dia).

Semi finish boring of both bores was checked for size, using a Telescopic Bore Gauge, leaving 0.2mm for finish boring :-


Set and lock an External Micrometer to the (28mm in this case) bearing outside diameter :-


Then use this to set the Bore Gauge ready for finish boring :-


Checking the finished bore for size (Bored to Bearing Dia plus 0.005mm), for the drawing stated "Tight push Fit" :-


The front 32mm bore was done in the same way and then a final skim of the front face :-




Edited By Nick Hughes on 22/01/2019 18:21:53

Emgee22/01/2019 18:55:28
1548 forum posts
222 photos

Looking good so far, very close tolerances.


Nick Hughes26/01/2019 17:55:52
225 forum posts
132 photos

Fridays job was to screwcut the thread for the retaining collar:-


Then using this expanding mandrel in the 28mm bore,


Finish faced the second face to achive the final overall length (used the power cross feed),


Then the height from compound slide face to spindle centre line was measured, using a turned bar and gauge blocks (slips),


Today was on to the compound slide mounting face:-

Clamped to a small angle plate and the cast face leveled,


Then after roughly centering the face with the spindle, the face was skimmed enough to clean up and provide a true face for the next operation,


After skimming, the part is clamped on to the machine table and after centering the boss under the spindle to a scribed centre point, the clamping stud clearance hole is drilled through into the cavity seen in the previous photo,


Next was to determin the amount of material, that needed to be removed, to bring the bore centreline in line with the lathes centreline.

This used the expanding mandrel from earlier, gauge blocks and a precision ground block to clamp the part down onto (V block in this case) and some arithmetic.


Then re-mount the part on the angle plate, level the face as before, centre under the spindle by clocking in the drilled hle from earlier, touch on the face and then remove the amount determined previously from the face,



After the face was completed, a smaller tool was fitted in the boring head, the cavity bored to diameter and faced to depth (clearance for the Myford four way toolpost ratchet if it's fitted),




Final operation for today:-

After clocking the angle plate parallel with the X axis (left to right), to act as the alignment datum for the next two operations. The previous mounting face is now held against the angle plate and the part clamped down on to the machine table, the bore aligned with the spindle by clocking in again.

Then the three M5 tapped mounting holes were machined using the machines DRO Circular Hole Pattern function.





Edited By Nick Hughes on 26/01/2019 18:13:15

Nick Hughes29/01/2019 11:49:37
225 forum posts
132 photos

This morning before setting off for my afternoon shift:-

Drilled and tapped the mounting holes for the Belt Guard/Motor Mount.

Clamped to the previously aligned angle plate (a bit higher this time to make access easier). Then clocked in the main bore and set this as both X and Y axis Zero,


The holes are drilled, tapped and chamfered using the DRO oblique line of holes function, in the same way as the cover previously.

Note the two types of Machine Taps. The Bright one on the right, is a Spiral Flute for the two furthest Blind holes and the Dark one on the left, is a Spiral Point, used on the nearest two through holes,


Thankfully the holes lined up,


Just the lubrication nipple hole boss, to face, drill and tap and another part will be finished,


Edited By Nick Hughes on 29/01/2019 12:14:27

Nick Hughes01/02/2019 10:48:23
225 forum posts
132 photos

Drilled and tapped for the lubrication nipple this morning:-

To centre the hole in a boss, I use a washer that is close to, or slightly smaller than the boss dia and with a drill shank or rod, that is a close fit in it's hole held in the chuck (use an ER Collet chuck if using a drill, as it holds on the drill flutes better), put the washer on the boss, lower the drill shank/rod into the washer hole (but keep it just clear of the boss face) and then simply move the table around until you are happy with the position, then drill as usual.


As my plan is to machine all of the cast items first, the next on my list are the Wheel Guards and I should be starting on these tomorrow.


Edited By Nick Hughes on 01/02/2019 10:55:15

A Smith01/02/2019 11:54:29
40 forum posts
3 photos


Really interesting. Please keep posting.


Nick Hughes02/02/2019 12:55:33
225 forum posts
132 photos

On with the External 3" Wheel Guard castings:-

Two identical castings are supplied and the machining converts one to the inner guard, by removing the boss,

Held internally, just to get started quickly,


A light facing cut (after the boss has been machined off), just enough to clean up the whole face.Then the casting is measured to work out how much to remove off each face (in this case the light skim was enough for this face)


Reversed and held externally, faced to length, then the internal features machined,





The outer guard is machined in the same way, only this time the boss is left on the casting,




Drilling and milling tomorrow, IF the hangover after tonight is not too bad!

Edited By Nick Hughes on 02/02/2019 12:59:57

Nick Hughes04/02/2019 18:42:18
225 forum posts
132 photos

Sunday afternoon, only slightly hungover:-

Clocking the inner guard bore, concentric to the rotary table axis, (the DTI is stationary and the table rotated),


Then clocking to the spindle axis (this time the DTI is rotated around the bore),


Next the outer 3 tapped holes. This used the DRO Circular Hole function for the positons and the hole to boss balance was achieved by lightly spotting each position and if needed, the table was used to rotate the part, the hole positions re-spotted and when an acceptable balance has been reached, the rotary table is clamped and the holes drilled, tapped and countersunk,


Without changing the angular position of the the rotary table, the inner countersunk mounting holes were completed, once again using the DRO function,


The outer cover was setup and drilled with clearance holes in the same manner (but without the inner countersunk holes).

On to the cutouts. The chuck jaws would foul the cutter and so the covers are clamped directly to the rotary table, then aligned in the same way as previously,



The outer cover has a 0.5" radius at the intersection/bottom of the cutout, so this was bored first,


Then one of the clamps is re-positioned and the sides milled to blend in with this radius,






The assembly so far,


Edited By Nick Hughes on 04/02/2019 19:04:14

Nick Hughes10/02/2019 13:20:43
225 forum posts
132 photos

Last weeks mission was the Cup Wheel guard and motor pulley:-

The single casting supplied makes the inner guard, outer guard and a small motor pulley.

Centred and rough turn the pulley


After boring and reaming, the belt grooves are cut (yes I do use HSS sometimes),


Then part off the motor pulley and reverse the casting in the chuck, to bore the outer guard,


Part off the bored outer cover and the remaining casting produces the inner guard,


The inner guard casting is turned to a sliding fit in the outer cover, faced to length and then parted off the chucking piece,




Setup the inner guard in the dividing head, to drill and tap the two outer cover clamping screw holes,


Then the outer sliding cover slots,




Checking the alignment before taking the outer guard off the dividing head, just in case there was some "adjustment" required to the slots.


The cutouts and mounting holes are then done in the same way as the previous External 3" wheel guards,


Lining up the cover for the rotary Zero degree starting point (after clocking the cover in to the rotary table and spindle) for the cutout. The inner guard was lined up in the same way,


Just the screws to shorten and then a radus to file on the open ends,


The final casting provided is for the Large motor pulley, but that will have to wait until next weekend.



Edited By Nick Hughes on 10/02/2019 13:24:49

Nick Hughes16/02/2019 16:15:02
225 forum posts
132 photos

This morning was Large Motor Pulley (For when internal grinding) time:-

A straight forward facing, turning, boring and reaming job.

Face aprox half the total stock, off what will be the back face,


After centre drilling for tailstock support, turned the O.D. to size and formed the belt groove. Followed by drilling, boring and reaming.


Then held in the 4 jaw and clocked true, faced to width, finish turned/faced  the boss and recess,



On to broaching the 4mm keyway (Also did the smaller pulley machined earlier),


Always a relief when it fits,


Final job was to set the pulley up on the mill, and drill two 9.5mm holes, for access to the motor mounting bolts during belt tensioning.

Clock/Align to the spindle (Rotating the DTI around the boss) and set both X and Y to Zero, either on the machine dials (But remember the direction you approached the Zero point, so that you can allow for any baclash when pitching over to drill one of the holes), or on the DRO (no need to worry about backlash with a DRO)


And then simply pitched over both directioins in X, to Centre drill and then drill through,


That completes all the castings and so tomorrow (hangover permitting again) will be the Spindle.

Edited By Nick Hughes on 16/02/2019 16:24:21

Nick Hughes20/02/2019 18:54:10
225 forum posts
132 photos

The raw matereal for the spindle is 1" Dia and will not fit up the Myford spindle, so in order to face and centre both ends, ready for finish turning between centres, I used the fixed steady:-

Clocking a short piece of 1" Dia stock (only had brass), to check it is running true. If I had a slightly larger Dia piece, I would have used that and turned it down to 1" to ensure true running,


Then clamped the Steady to the bed and set the pads to this,


After setting the pads, slid the steady along the bed and re-clamped, loaded the spindle stock to the chuck, then faced and centred the first end, reversed in the chuck, parted off, faced to finished overall length and centred,



With support now available from the tailstok and Revolving Centre, the spindle is roughed out,


Preparing to finish turn between centres, starts with truing up the spindle "live" centre (this should be done each time the centre is re-fitted to the spindle and is why they are soft),


Then the revolving tailstock centre is replaced with a carbide tipped "dead" centre,


The spindle is now semi finished turned and during this, the tailstock alignment adjusted, in order to produce a parallel shaft. Then finished to the drawing specified 12mm "close sliding" fit for the ball races and the smaller 0.375" Dia for both the drive pulley location and thread,


Reversed and the shorter "Wheel" end finish turned,


The tailstock centre is now changed for a Half Centre, to provide enough clearance for the screwcutting tool and both ends screwcut 3/8" x 24 UNF (should be 3/8" x 20 BSF, but I already had the UNF threading inserts and taps)


This final op, was drilling and tapping the end M5, as I had forgotten to do this whilst facing and centering the ends. Held in the ER spindle nose collet chuck, to prevent damaging the previously finished turned Dia,



The next thrilling installment, will be the Spindle Drive Pulley!

Edited By Nick Hughes on 20/02/2019 19:24:05

Michael Gilligan20/02/2019 19:05:24
15891 forum posts
693 photos

Classy work, Nick ... keep the 'masterclass' coming.


Nick Hughes21/02/2019 21:05:59
225 forum posts
132 photos

Thanks to everyone for the encouraging comments.

The spindle drive pulley starts out as a 2 1/4" length of 1" Dia free cutting mild steel bar and when finished, must run as true as possible:-

To start, the bar is rough turned to 0.020"/0.5mm above the belt groove flange finished Dia, far enough along to enable access with the tooling, when the bar is reversed in the chuck, to rough and finish the full pulley form, without removing from the chuck. Doing this should ensure the minimum of runout,


Reversed in the chuck and because I had no LH turning tools available, I inverted the tool and ran the lathe in reverse. Taking it steady with the depth of cut, there was no hint of the chuck unscrewing!

Again I left 0.020"/0.5mm on all dia and 0.010"/0.25mm on all faces for finish turning, after completing the bore,


After rough turning the outside, the bore is drilled through tapping size, then bored and reamed for the plain locating bore portion and then tapped. Final boring op was to cut the 30 Deg chamfer on the bore, ready for the centre used when finish turning the outeside and forming the belt groove,


All finished but resisting temptation to part off from the chucking stock, As you'll see, leaving it on the stock makes the following operation a lot easier,


The chucking stock is now used to hold the pulley for drilling a 4mm cross hole, used to tighten it on the spindle.

Held in a V block, clamped to the machine table and the V block aligned with the X axis,


Then to make finding the centre easier, I screwed in the spindle and pitched over to the centre from that,


After removing the spindle, I "wobbled" the pulley face, moved to the hole position and after centre drilling, used a 4mm ball nose cutter to start the hole (I find a ball nose cutter after center drilling, works better than using a normal flat face cutter)


Follwed by drilling through,


Back in the lathe and part off from the stock,


Reverse in the chuck, face to length and chamfer the thread,



Final de-burr and it's done!


Next will be the two Spacer Tubes.

Edited By Nick Hughes on 21/02/2019 21:29:10

Nick Hughes23/02/2019 15:16:57
225 forum posts
132 photos

Fridays job was the Bearing Spacer Tubes. Staight forward turning, the outer from 1 3/8" Dia and the inner from 3/4" Dia FCMS:-

The outer first. Faced centred and rough turned,


Then the undercuts,





Bored to finish size and finish turned,



Parted off, reversed in the chuck, faced to length and the edges lightly chamfered,


The inner spacer is simply a tube, turned using the same sequence as above. The only difference was that the bore was reamed to size after semi finish boring,


Today was on to the Wheel Flanges and the Bearing/Spindle Retaining Ring:-

Once again straight forward turning for the wheel flanges, one plain reamed bore and one tapped.

Turned, bored, counterbored, reamed or tapped, then parted off from the stock and set aside, until after the Retaining Ring,



The remaining stock had a chucking piece turned on it, to make holding in the chuck to make the Retaining Ring easier,

After turning, forming an undercut to below core dia and boring, the outside was screwcut to fit the Spindle Housing.

Still waiting a month after ordering, for the external threading insert, I decided to use the internal tool and insert!

Done by inverting the internal tool, running the spindle in reverse and cutting the thread away from the cuck (starting from in the undercut),


Using a Full Form insert that also cuts the thread crest, it's easier to start with a slightly oversize blank Dia and sneek up on the final size/fit,


After parting off, I bored some soft jaws to hold this ring and the wheel flanges for facing to width and chamfering,


The soft jaws also came in handy when setting up on the miller, to drill the tightening holes (The bore was aligned by "clocking in" and holes placed as with previous items),


All the Turned Spindle parts,


Finally the complete Spindle Unit,


Apart from a bit of fettling and painting of the castings, that completes the main grinder.

The next and probably final installment, will be machining the internal grinding extensions.

Edited By Nick Hughes on 23/02/2019 15:39:52

thaiguzzi23/02/2019 15:25:16
698 forum posts
131 photos

Now thats what i call a photo essay.

Thoroughly interesting, and well described and photographed..


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