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| vintageandclassicrepairs:
Hi Chipenter, It may be worthwhile fabricating a new slotted "banjo to accomodate the different gears needed? On a couple of lathes I worked on the wheels were 127 and 125 teeth to provide the metric threads the pitches would then be "near" the imperial settings (ie. 20 tpi = 1.25mm so to speak) This seemed easier to convert in my scrambled brain :smart: rather than your 127/100 combination (5:4 ish) I always checked the pitch with a dial gauge against the carriage before cutting metal HTH John |
| chipenter:
--- Quote from: vintageandclassicrepairs on June 24, 2015, 06:02:18 PM ---Hi Chipenter, It may be worthwhile fabricating a new slotted "banjo to accomodate the different gears needed? On a couple of lathes I worked on the wheels were 127 and 125 teeth to provide the metric threads the pitches would then be "near" the imperial settings (ie. 20 tpi = 1.25mm so to speak) This seemed easier to convert in my scrambled brain :smart: rather than your 127/100 combination (5:4 ish) I always checked the pitch with a dial gauge against the carriage before cutting metal HTH John --- End quote --- That was my first thought to , I alredy have 100 and 40 gears and the 32 127 should be delivered tomorow , all I have to do is bore them to fit and bolt the 100/127 together , and should be a simple change over involving two bolts . |
| Pete.:
--- Quote from: vintageandclassicrepairs on June 24, 2015, 06:02:18 PM ---Hi Chipenter, It may be worthwhile fabricating a new slotted "banjo to accomodate the different gears needed? On a couple of lathes I worked on the wheels were 127 and 125 teeth to provide the metric threads the pitches would then be "near" the imperial settings (ie. 20 tpi = 1.25mm so to speak) This seemed easier to convert in my scrambled brain :smart: rather than your 127/100 combination (5:4 ish) I always checked the pitch with a dial gauge against the carriage before cutting metal HTH John --- End quote --- 127 teeth provides perfect transposition. If you only wanted 'near enough' there are more conveniently-sized combinations that produce good enough threads to make fasteners etc. |
| chipenter:
Gears arived today got them bored out and bolted together , the fixed shaft is 3/4" x 2 1/4" and I will make spacers one 1 1/2 x 3/4 bore and one 3/8 x 11/16 bore for the lead screw end . |
| chipenter:
Got it finished the gears are nice and quiet and cut a 2mm pitch thread , using the instructions from Matt Tinkers Eggwick thread on screw cutting up to a shoulder , I have learnt something today thanks to Madmodder . |
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