Myford Saddle Stop – Hemingway

[Adrian DixonParticipant @adriandixon92675]

About twelve months ago I purchased a Myford Saddle Stop kit but on closer examination I realised there were issues with clearance for the ‘T’ bar that attaches in front of the rack. I enquired with Kirk at Hemingway and he did concede that he had heard of some problems, but believed they were only slight and that most were okay. I put the kit to one side.

Looking at it afresh I removed the leadscrew guard and then slacked one of the rack securing screws and backed out until it fouled the passage of the saddle over it. On the drawing the strip (and as supplied) is 1/4″, however the maximum protrusion on the screw before fouling was about 0.232″.

I then made a bobbin to fit the screw and of the same profile as the ‘T’ bar – i.e. 0.455″ and 3/8″ dia and with the 3/8″ dia at 1/8″ wide but the 0.455″ dia reduced to give an overall thickness as 0.232″

On trial with this fitted the saddle would not pass as the plate that holds the front of the saddle down on the bed (Drg. Ref. KA7 – Part No. A9185) fouled the bobbin. I then reduced the bobbin diameter of 0.455″ in stages until it would just clear and by then the diameter was 0.410″ which is only 17-1/2 thou a side larger than the 3/8″.

The lathe in question is a long bed S7 of 1980 vintage with power x-feed. I also have an earlier long bed S7 (pre power X-feed) and whilst I haven’t examined as closely it does suffer the same problem.

Has anyone else made on of these kits and had the same problem?

It is livable with, nut the sizes are getting very neat. I did wonder about dovetailing rather than the ‘T’ section. Any thoughts?

Adrian

[Adrian DixonParticipant @adriandixon92675]

Clearance issues

[NJHParticipant @njh]

Hi Adrian – I have sent you a message.

( Log in and look in “My Messages” )

 

Regards

 

Norman

[HasBeanParticipant @hasbean]

Typically I’ve found this post having just received my saddle stop kit.

In the instructions it mentions that the ‘T’ bar needs to be removed when not in use if you have a power cross feed model

 

Have either of you gents found a way around this ?

 

Regards,

 

Paul

[NJHParticipant @njh]

Hi Paul

 

That’s very interesting as my instructions state :- ” The guide rail can remain permanently in place – its proportions will allow the saddle and rack gears to pass over without hindrance” ( The date on my instructions is 2009 – is the date on yours different?)

 

Now as Adrian has discovered, and I can confirm, this is not the case. I ‘ve not been able to get out into the workshop since this came up, other than to confirm Adrian’s findings, but hope to do so soon. It would be a real pain if the guide rail needed to be removed each time and would, in my view, greatly reduce the value of the attachment. The beauty of the design should be, as stated in the blurb, …..”the device is fitted and removed so quickly that you will save time when producing a single part “. Maybe we can find a way around the problem.

 

Regards

 

Norman

Edited By NJH on 11/01/2012 12:35:29

[HasBeanParticipant @hasbean]

Hi Norman,

 

My instructions are 2009 also but on page 1 under ‘The Guide Rail’

 

“….the Guide Rail can remain permanently in place – it’s proportions allowing the saddle and rack gears to pass over without hindrance. On some lathes however (notably power cross feed models and those with re-ground beds), this is not possible and the rail must be removed after use.”

 

This is a bit of a b****r if that’s the case. There must be a way of altering the rail to make it fit somehow, or possibly make it easier to remove rather than bolting/unbolting all the time.

 

However this ‘project’ is lower on the list at the moment, I have to finish my knurling tool first which I started when my daughter was born (she was 13 last week &nbsp

 

Regards,

 

Paul

 

[Adrian DixonParticipant @adriandixon92675]

In the absence of any further responses and now having completed the saddle stop I am able to offer the following information that may benefit others in the future(?). This applies to the installation for my long bed Super 7 with power cross-feed of 1980 vintage and may differ for other machines……….certainly my earlier pre power x-feed machine does vary slightly. There is very limited clearance for the saddle / apron assembly to pass with the T strip fitted due to the proximity of the saddle plate above, the rack pinion shaft below and the apron to the front. Before starting it is necessary to remove the cast alloy leadscrew guard and the blackened sheet steel piece behind it as these will foul the T strip. Once the T strip is fitted the sheet item can be reduced by about 1/16” on its inner edge to clear and a small corner (maybe 1/8” x 1/8” ) cut from the bolting flange of the guard. This does mean the assertion that ‘no modification to your lathe is necessary’ is not strictly true!

The T strip that attaches over the rack was machined from 5 x 12mm BMS strip in lieu of the supplied ¼ x ½” and the width was reduced from the stated 0.455” to approx 0.430”.

The 3/8” was maintained but the 1/8” thicknesses were reduced to approx 2.5mm each – although I erred on making the thickness of the top of the T slightly under and preferring to leave a shade more meat on the lips on the cast iron block.

The holes for securing to the lathe were offset towards the top edge of the strip, thus lowering the strip, by drilling about 12 thou off centre – without this the strip fouled the plate that holds the saddle down on the lathe bed. Note that due to the reduced thickness of the strip you cannot use 2BA cap screws as there is no room for metal under the head! My solution was to countersink and substitute 2BA x ¾” long socket head countersunk screws. As my machine is a long bed I made the T strip about 14” long and span 5 rack screws rather than 3 as per drawing – but note that the pitch of the screws is 3.300” on my machines – not 3.5” as stated on the drawing, though to be fair they do state to use the rack as a drill jig. I didn’t, just relying on the feed screws on my D/W for spacing and all was ok.

The position of the hole, in the CI block, for the brass clamp pads for the tee needs to be relative to the ‘T slot’ not the edge of the block.

The suggested woodruff cutter was no longer suitable due to the size changes and I opted to make my own cutter from 5/16” dia silver steel with a slot across the end and a small scrap of carbide brazed in and ground up – looks a bit like a boring tool. For security I threaded the holding end and used in the autolock chuck and basically flycut the undercuts one side at a time.

Despite taking care positioning the hole for the brass clamp pads for locking the 3/8” dia. bar the centres fell too close and the 2BA cap screw would not fit. The simple expedient was to locally turn the threads off. assemble the pads and screw to the block and then slide the bar in place. Take care – you have been warned!

(Continued in next posting).

Edited By Adrian Dixon on 11/01/2012 21:11:36

Edited By Adrian Dixon on 11/01/2012 21:11:59

[Adrian DixonParticipant @adriandixon92675]

(Contd. from previous posting – text was too long for one!)

I was lazy when it came to the thread indicator attachment stud and did not make the bolt come stud as per drawing but used a length of commercial ¼” BSF studding I had in stock with the original nut to secure the indicator. Then came the next problem, the stud did not line up with the tapped hole in the 3/8” bar, this despite careful marking for the hole in the block as recommended in the instructions. The cause soon became apparent and was no reflection on my machining nor the design. Without the thread indicator fitted all was perfect, the faces on the indicator were not square to the bore nor parallel to each other, hence when the nut was tightened the stud deflected off centre! To be fair to Myford we are trying to do something that was never intended, hence this out of square was previously of no importance. I turned up a stub in the chuck that was a push fit in the bolt hole in the indicator and skimmed the faces true and all was well.

The final word of warning…..all then fitted and worked well but if you have a power cross-feed machine be aware that the inner end of the shaft that carries the push – pull knob for engaging and disengaging the feed can foul the T bar at the inner end of travel with possibly severe consequences. There is ‘free’ movement at the inner end of the travel of the shaft after the drive is disengaged so I removed the knob and both circlips (one in front and one behind the knob) and fitted a 1/16” thick washer behind the second circlip which prevents the shaft travelling far enough in to foul the T strip. Another option may be to chamfer the ends of the T on the front face so the shaft will ride out and thus not cause a jam up. Your choice.

I’m sorry if this is long winded, but it is all fairly simple really and may help someone in the future. At the end of the day we are trying to shoe horn stuff into places that was never intended, hence maybe only fair to expect some issues?

Regards,

Adrian

[NJHParticipant @njh]

OK

I got out to the workshop this afternoon. I fitted my guide rail ( it covers 3 rack fixing screws) to the extreme right hand end of the rack. I removed the chuck, moved the carriage to the right until it fouled on the guide rail and measured the distance from the spindle nose to the left hand side of the carriage. It was 9 inches. I’m not prepared to live with that limited movement all the time. I then considered maybe shortening the guide rail such that it only covered the last two rack fixing screws. As far as I can judge this would increase the gap to 12 1/2 inches and, whilst better, I don’t think I want to live with that either. I can imagine forgetting it was there, winding the carriage rapidly to the right and doing goodness knows what damage to the PCF.

Adrian – any further progress at your end?

 

Regards ( and frustration!!)

 

Norman

 

 Good grief Adrian – that was a quick response!

Edited By NJH on 11/01/2012 21:13:56

[HasBeanParticipant @hasbean]

Thanks for the info gents.

 

Adrian, I’m starting to quake in my boots now at the thought of this but thank you very much for providing light at the end of the tunnel!

 

Norman, good luck with it as I’m certain that you’ll end up with something far superior to whatever mishmash I end up with.

 

Regards,

 

Paul

[Author]

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