Quorn cutter grinder tool holder support

I am slowly getting to understand how to manipulate and use my recently purchased Quorn tool cutter grinder.    One frustration that kept cropping up was the workhead assembly slip rotating on the bed bar. This usually happens when there is a need to slide the tool holder head back after a referencing action.  This messes up the reference setting.

I chanced upon a thread on the MEW forum where a John P had solved this problem with a parallel support bar assembly.   This utilised the 1/4″unused hole in the toolholder side wall.  There are a number of ways to fabricate this fixture but the important aspects are that it should be robust and must ensure a parallel motion along the support rod.

quorn cutter grinder tool head support bar
The cutter grinder tool head support bar mounted on my Quorn

I opted to model the bracket in Fusion 360.  As there will be little stress on the bracket in use I opted to mill it from 15mm cast aluminium to give a 12mm finishing depth.  Here is the pictorial view from the Fusion desktop.

Fusion 360 model of the Quorn cutter grinder tool head bracket
Fusion 360 model of the Quorn cutter grinder tool head bracket.  The bracket measures around 90mm end to end.

The bracket has a 5/8″ hole to match the Quorn table slider rod and a 10mm hole for the new parallel support rod (sorry about the mixed dimensions but my Quorn is an Imperial model and most of my stock is metric).   

Side #1 CAM operations are to clean up skim the stock top surface followed by profiling the two holes and the outside shape.  Side #2 is to invert the model and deck the excess material.   The clamping slots, the flat adjacent to the 5/8″ hole and the M4 tapped holes are all supressed in the CAM and manually cut post CNC operations.

The model has two tabs adjacent to the 10mm hole.  These have no relevance to the use of the bracket but are there to make the width of the model equal.  This negates the need to use soft jaws to hold the model when undertaking side 2 operations to deck off the excess stock material. The decking brings the model to 10mm finishing depth.   These two tabs could be ground off afterwards if desired. 

I did consider grub screw clamping of both bars but there was a danger of deforming the associated bars.   It was easier and more elegant to design slot clamps into the Fusion model. The clamping slits were cut post CNC machining on my BK3 bandsaw.   (Try cutting straight slots on a BK3 without a decent fence and support bearings.) The parallel nature of the finished model width as mentioned above makes this a simple process against the bandsaw fence.

The two M4 clamping screw holes are drilled prior to the slots being cut.  The holes are drilled 3.3mm through and then M4 through threaded.  After the slots are cut one half of each hole is clearance drilled to M4. 

The flat adjacent to the 5/8″ hole is the last ‘after CNC’ machining operation.  This flat gives the clearance needed to allow the bracket to slide under the Quorn toolholder referencing dial.

The gliding bar is mounted in the spare hole in the tool holder side wall.   This hole in my Quorn had been drilled 1/4″.   The rod profile was turned with a centre from 10mm silver steel to have the 1/4″ section and then a short section threaded M6.   Note that I also made a brass washer profiled to match the rear face of the through hole in the body.  Like most of the Quorn casting holes this had a step segmented surface aimed at stopping bolt head rotations.

Fusion 360 pictorial view of the assembly
Fusion 360 pictorial view of the assembly
Quorn cutter grinder tool head support components
Quorn cutter grinder tool head support components – this shows the bracket with support bar in place, supporting rod and profiled washer.

Mounted on the Quorn, the assembly sat nicely parallel, is very solid and stable and does an excellent job of stopping the head drooping.  My frustrations over this aspect of the Quorn are eased for the time being.

If any readers want the Fusion file or dimensioned drawings then add a comment below.

UPDATE : – The bracket should be rigid enough when 3D printed instead of machined from solid. Here is a ZIP file containing  the support bar clamp version v5 as a STEP file.  All the other parts are straightforward lathe operations.

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Using Raaco section boxes for fastener storage

I am a great lover of the Raaco 18 section storage boxes for my various sizes and ranges of nut and bolt fasteners.   These boxes are not unduly expensive and are very durable with a sliding locking latch (assuming you don’t forget to slide it place – see below). 

 

To date these boxes have been stowed stacked one of top of the other on the shelf above my office workbench.   Come the need to get a particular size fastener for a job I can bet on the box I need to access being at the bottom of the stack.   This can get frustrating and can also be risky because if I haven’t fastened the lid properly there is an ever present possibility of a lot of fasteners hitting the floor with some associated colourful expletives.

As you have probably gathered from the previous post, this has been woodwork week or at least MDF week if that counts as real woodworking.  After finishing the storage box for my clock bushing gizzmo I still had MDF to spare. With some judicious juggling in Fusion 360, I came up with a design for a slide in storage rack for my Raaco box collection.   In fact there was enough MDF left over to make two of these.   I did have to buy in some 30mm x 2mm angle though. The design allows access to any fastener box without the need to shuffle the stack to get at the one I needed.  Joy of joys.

The storage unit is 300mm high and has MDF sides and back board.  I had to revert to a 1mm sheet of  aluminium for the top and bottom surfaces to get the optimum number of boxes to fit between the workshop shelves.   Each storage slot has an aperture of 250mm x 47mm (excluding the aluminium angle) and is 180mm deep.

The added bonus to the design is that the Raaco fastener slide is a very tactile grab handle to draw the wanted box out of the rack.  The feel of the slide also acts as a warning flag that the slide might not be correctly locked in place.

Yes I know it is all a bit anal.   Making things to make things etc but less frustration means more productivity … well that’s the theory.

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Rear Parting Tool Post on Myford Super 7

 I’ve been meaning for some time to make a rear tool post for my Myford Super 7 when parting off material.   There are various comments on the web about how a rear mounted blade is the best way to succeed for this activity.

Hemmingway Kits here in the UK offer a kit of materials and instructions based on the Geo. H Thomas design as detailed in his ‘Red Book’  (ISBN 1-85761-000-8).  This seemed like a good route to take.

The kit arrived with all the materials and documentation needed including a casting for the body of the post.  You do have to make a couple of cutting tools as part of the activity but again the material is supplied for this.  I found that having access to the Red Book in conjunction with the Hemmingway kit notes helped me better understand what was involved.

Having the Tormach CNC mill allowed me to depart slightly from the intended construction  but it all came together very well.   I had some Myford Aqua blue paint to hand from my Clough42 Electronic Leadscrew control panel enclosure and this finished off the project nicely as shown below.   However I do need to crop back the excess on the rear of the blades before blood is spilt.

Hemmingway rear tool post parting tool holder
The finished rear parting tool holder made from the Hemmingway Kit

Trial cuts have so far been excellent. I can now use the power cross feed when parting brass which is a major departure.  Overall a good addition to my workshop assets and a relaxing pleasure to make.

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Myford Super 7 backlash solution with thrust bearings

One Job Leads to Another

I had a job for a customer that needed two M18 screws cut on the ends of a  shaft.   I have never cut anything that size before but fortunately I have installed the Clough42 Automatic Leadscrew system fitted to my Myford Super 7 Big Bore lathe.

I tried some trial cuts using the Geo Thomas ‘Red Book’ top slide method but I found there was so much backlash on both the top slide and cross slide that I was struggling for consistency.   In the end I did a hybrid cut ‘nearly there’ using the ALS using plunge cuts and then I finished with a nut die that was happy to start on the part cut thread .   This gave me a clean finish to the thread and I was relieved to get the job done.   Note that my S7 is a ‘metric’ version but the leadscrew is Imperial so screw cutting using the ALS entails keeping the half nut engaged and reversing the drive.

With the job completed my thoughts came round to giving the Super 7 some TLC to try to improve the backlash issues.   I found various discussion threads about fitting thrust bearings to the cross slide and top slide but all referred to EBay thrust bearings that were no longer listed.   After some investigation I found Simply Bearings had two suitable items in stock.   The NTA916-TRA916 is a 9/16″ core diameter bearing and washers suitable for the cross slide and the NTA815-TRA815 is a 1/2″ set for the top slide.  I ordered two of each set.

The attached PDF link below gives details of how I implemented this modification.

Myford Super 7 Thrust Bearing Mods

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Adapter plate for a Tormach microARC to mount a Xin Dian centralising vice

I’ve made mention in another post of the arrival of the Tormach microARC to use on my Tormach PCNC440 CNC milling machine.   The microARC provides a 4th axis facility.

To date I have used this with the supplied chuck but there have been a couple of instances where a vice style stock mounting would have been useful.  I am indebted to David Loomes for bringing the Xin Dian centralising vice to my attention. 

Xin Dian centralising machine vice
The Xin Dian centralising machine vice

This is available from various sources on the Internet and at a delivered price of less than GBP100.   It is a lovely little vice.   It is supplied with an industry standard backing plate which is held in place with four M6 cap head screws.  The supplied backing plate is not suitable for mounting on the microARC .

A 3D model of the microARC is available as a Fusion file and this with some careful measurement allowed me to model a mounting plate for the Xin Dian to fit onto the microARC face.

As a secondary activity I edited the Fusion file to provide a simple sub-mounting plate for the Xin Dian vice on my PCNC440 tooling plate.

Details of both these mounting plates are contained in the PDF link below.

xin dian vice mounting plates

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