Member postings for S.D.L.

Longest Dinosaurs tooth 300mm / 12"

Steve

One of the interesting things with Barrys stripdown of the gearbox was the the O ring grooves, as the dimensions were decidly odd Barry sent me the dimensions and asked for my view on the circlips to use.

The dimensions were:-

Shaft :19mm Groove 18.5mm Width 1.3mm old circlip 1.0mm thick
Shaft: 18mm Groove: 17.0mm Width 1.3mm old circlip 1.0mm thick
Shaft: 15.74mm Groove: 15.36mm Width 1.22mm old circlip 0.94mm thick

The only one that is std that I could see is the 18/17 and that was after checking the imperial ones as well.

In the end I sugested the following sizes and comments.

Well all I can say is what a dogs dinner

D1400-019
D1400-018
D1400-016

I would get 10 packs as they are only a bit more than 2

If they don't look as if they will stay In place make a tapered mandrel out of steel
and lap the ID of circling with valve grinding paste.

Hopfully now that everything is sliding properly the circlips will stay in place.

Steve

And the last part of Barry's journey back to a working lathe.

After final confirmation that the gear selectors were engaged and working properlye gasket sealing compound was applied and the rear cover panel refitted. Where the missing screw had been (original hole filled with sealer) I managed to extend the tapped portion of what was left in the casting and fitted longer screws which gave some purchase.

Gearbox and shaft taper shear pins refitted. Note table used for changing gear wheels. Corner removed to allow door to open, override block top right engages with safety cut out switch for testing, and banjo rests on the extended piece when pivoted forward. Final photo shows everything panelled up and ready for testing.

Posted by Steve for Barry

Next Installment

Refitting the front panel. I had removed the three knobs to give them a good clean. Each knob has TWO balls, a spring and a tensioning grub screw so care must be taken not to lose any part. These were removed before driving out the roll pins securing the knobs to their shafts.

I used some M4 nuts and bolts in place of the roll pins to position the gear selectors such that the selector arms would line up with the gear trains. The selectors were very loose, so to keep them vertical I inserted some 15mm lengths of bamboo skewer and slightly compressed them against the front panel with bolts screwed by hand into the tensioning grub screw holes. This method worked well.

The technique I found worked was once the arms were vertical it eventually becomes possible to get the actuating cams to engage whilst pivoting the front panel against the bottom of the gearbox housing. Full engagement could be confirmed by looking in a mirror positioned behind the gearbox (as in the last photo) then moving the selector knobs in both directions. Once comfortable with the positioning it was a matter of applying gasket compound to the previously cleaned surface of the gearbox, repositioning it in front of the mirror and repeating the pivoting motion and confirming again that the selectors worked correctly before refitting and tightening the 5 front panel retaining bolts.

Loaded by Steve for Barry

Revers sice chamfering tool on CNC. for deburring the far side?

steve

Considering Barry did a conversion to three phase motor and vfd that was covered in MEW. Before this happened it will be a far better lathe than when new and shipped.

Steve

Next Installment

Although I had read it elsewhere, I was surprised at just how ineffective the gearbox drain plug was. It is around 20mm ABOVE the level of the inner casting. This results in a large amount of residual oil cascading out when the front panel is removed. Someone had suggested adding a drain hole at a more appropriate position, so that formed part of my project. I decided to fit a magnetic drain plug and sourced one from eBay. It required an M12 x 1.5mm tapped hole. After some deliberation I drilled a pilot hole 19mm up from the bottom of the front cover in the mill. The panel was turned over and a 14mm mill, centred on the previously located pilot hole, used to produce a clearance for the M12 tap. The panel was again turned face up and a 10.5mm tapping hole drilled. The hole was then tapped perfectly square whilst still in the mill. The finish on the front panel although adequate for a panel face was not deemed good enough to guarantee a good tight fit when the magnetic drain plug crush washer was compressed, so a light skim with a 20mm end mill improved that area. I used a 20mm ‘Q’ cutter to produce the hole in the front aluminium cover plate, the centre of which had also been located using the pilot hole..

The last photo shows the reworked gear to the left on its keyway and the now smooth triple gear assembly on its shaft & keyway

Posted by Steve for Barry

Reminds me of the old 80/20 rule, get 80% of a broduct for 20% of the cost, its that detail that costs the money,

Steve

Making the missing gear

Whilst waiting for the outstanding gear to arrive it dawned on me that there was a perfectly serviceable gear on the old triple gear assembly with the correct number of teeth. It would require removal of two of the three gears from the shaft, boring and reaming the hole to 16mm diameter then milling to the correct overall width. The lathe was perfectly useable without the gear box, but I did miss the power fed when boring the hole out. These stages are shown in the photographs. Although it looks otherwise, the shot where the gear is being milled is actually ‘finger nail’ smooth and not scored across the diameter.

There only remained the lack of a keyway …. At last, an opportunity to use a broaching tool inherited from a former club member’s workshop for the first time. After a bit of research I found Michael Cox’s article on making a simple internal keyway broach (MEW Issue 184, page 47) and set about modifying a length of 16mm silver steel. The broaching tool travel was pretty limited so the tool had to be customised. I milled a 4mm slot into which I set a length of 4mm square HSS tool steel. I didn’t grind the end, but used it as purchased. An M3 grub screw approximately 20mm from the end of the tool steel is used to progressively advance the cutter into the work in minute increments. After a considerable amount of time, copious amounts of cutting fluid and two blisters, the task was completed. It was slow, hard work but well worth the effort in the end.

Posted by steve for Barry

Hi

Next set of Photos and text from Barry

In order to disassemble the gear trains I manufactured a simple gear puller as shown for the roller bearings. It may be recalled that when I complained about the stiffness in the gearbox Warco (who had the lathe back for rectification under Warranty) attributed it to ‘swarf’ under the gear selector knob. As can be clearly seen that was NOT the case at all. Someone at the factory in China had obviously struggled to get the triple gear assembly to smoothly slide along the gear shaft and had resorted to agricultural means of persuasion in attempts at achieving free movement!

I was not impressed with this at all and will let the photographs tell the tale. It was obvious that the key had to be replaced. The original key was wedged in place so I had to mill it out. As can be seen in one photograph there were several nicks along the edge of the keyway itself which I dressed prior to fitting the new key. I purchased a 4mm square length of keyway bar from Simply Bearings, cut to length and ground the ends to suit. Fitting this was not straightforward and I sensed that the key slot itself was slightly offset and found the new triple gear assembly was binding along the shaft. I resolved this by lightly scraping the shaft either side of the key with the square end of a small flat file. Eventually this resulted in a smooth sliding action along the keyway.

Posted for Barry by Steve.

Hi

Barry has been busy stripping his gearbox down and repairing and this is the first in a series of posts showing the cause and the repair.

At last I’m able to finish this Gearbox strip and rebuild report. Although I had two gears from Warco (the double and triple gear assemblies) the third gear was on a 12 week back order from China. THEN lockdown arrived and things slowed considerably, so I decided to get as much done as possible prior to the third gear arriving. First surprise, on removing the Gearbox from the lathe body, was when I was removing the rear cover to gain access. After removing 7 of what should have been 10 screws I realise that there was NO screw fitted at the second location in from the left on the bottom row, and the hole had been filled with sealer! When the sealant was removed it was apparent that the hole had been drilled way off centre leaving little thread in the casting.

Inboard of the top row of holes there was a burn mark clearly visible on the rear cover plate. When released it was obvious that the inner face of the cover plate had been ground down – to give clearance between the cover plate and one of the gears! See photos showing the teeth of the larger gear clearly above the ground rear face of the casting…………!

I am still unable to post photos onto this Forum for some odd reason, so Steve has again kindly stepped in to post on my behalf.

Posed by Steve Larner for Barry

The McMaster website shows Hex Dies as thread repair as per UK practice but they do show the conversion holder in the clip below.

Would be easy to mage similar at home

Steve

Have you checked that the insert hasnt chipped / worn on one side leading it to wander.

Its better with power feed you need to cut not rub.

Steve

A quick search advanced search on Ebay for Viceroy TDS shows prices of 450 - 500 pounds.

I would try to sell on this site first and / or here **LINK**

Steve

What you have worked out is correct M? with no further info is coarse used to be standard practice to only put pitch if non coarse although sum machine shops ask for pitch it in all cases now days.

Steve

Thanks for the Info

Steve

Was that direct onto steel or with special primer?

Nice Engine

Steve

From memory when we used to use sandvik internal boring bars the shim under the insert has to be different angles for different TPI inserts, there were at least 3 angles maybe more. I suspect for the feed in to be to theory dimension the angle needs to be correct.

Steve

Can you post a picture of the diagram you are using?

Steve

Strange I thought their was bad weather before the Jet age.

Steve