Hi Ryan

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Is? your current chuck a direct mount or does it have a mounting back plate?? Also the standard size three jaw chuck for a Lot 3 4 and 5 was four inches.? The standard offered 4 jaw was a five inch.? There are a number of fairly good quality 4 inch three jaw chucks available on a number of eBay sites.? As to new mounting back plates there are none to be had so you have to make them.? I have made new back plates for a Dalton? Lot 3 4 and 5 using a 1 inch 10 back plate meant for a small Atlas or Craftsman lathe. ?These usually have sufficient material around the spindle thread that allow you to open them up to Dalton size of 1 ? - 12.

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Dennis

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Here is a drawing we did a few years ago.? This shows what a six inch back plate looks like.? It can be made any outside diameter to fit whatever size chuck its being made for.???? Dennis

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Hi Glen???

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Say I have an idea that you and I could help these guys with back plates.? I did some looking last night and there are some very good examples of back plates for up to 5 inch chucks on eBay for cheap.? These then need to be bored and threaded.? Was wondering if I provide you with an almost new Dalton spindle used on the Lot 3 4 and 5 lathes do you think you on your CNC lathe could finish the thread and register counter bore for a reasonable price.? I would provide the back plate blanks.? These back plates that are available are almost cheaper than purchasing a chunk of cast iron to make them from.? I can do it on my Hardinge HLV-H but like you my back is just not letting me stand at a lathe any longer. ?I was thinking of maybe picking up six to eight of these back plates for? the guys.?

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Also there are a number of decent looking 4 inch 3 jaw chucks for sale on eBay for not a lot of money.? Looks like you can pick up a 4 inch for under $75 bucks with shipping.?? It’s funny Glen but the Myford lathes use a chuck that has a 1 1/8 – 12 spindle thread.? Was thinking they would be also easy to enlarge to Dalton size by picking up the thread.? You and I have done that before I know.? It’s to bad they are so expensive.? ?Was just a thought when I seen them for sale on eBay.?

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On a side note Glen seeing as my email service will not let you send me an email I have been working in the shop at Florence updating Inverter control stations.? I put a push button control station with speed control pot on the little Rockwell mill and now I am doing it to the little Dunlop drill press.? May put one on the Rockwell drill press as well as we are using a Teco inverter on it.? I even have that little Lip French made surface grinder down at Florence now and we run that with a Teco inverter.? I think we have seven machines now running on three phase inverters at the Florence shop.? Dennis

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Glen I have several Dalton spindles on the shelf but the last Dalton Lot 5 I did as well as the peddle Dalton have almost new spindles in them as the? lathes were basically new.? Dalton spindles are soft and tend to wear quickly.? So making a back plate for a fresh spindle they would fit almost any spindle out there I would think.? Dennis

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I bought a two 5" back plates for the Select recently, both were Myford, and for the very planning you had, a single pass bores the old threads out and one small finishing pass brings them to the 1 1/4" pre-thread bore.
?I also did something I'd never done before, I made a test spud with both the register diameter on one end and the spindles threads, using a thread mic to a very close fit, on the other end. This was used when creeping up on both in the back plates, they are without a doubt the best fitting back plates I've ever made.
?Both the 4 jaw and the 3 jaw were extremely cheap.
?To turn the 3J plate into a "Adjust-Tru" type I expanded on an idea I saw on youtube, a guy made the register of a purchased "made to fit" back plate another 3/8" longer and threw away the dust cover inside so it would fit.
?That gave him lots of room to have the four 3/8 adjusting setscrews something to push against, as the register on the original was only 1/8" or less.
?I knew what he didn't seem to be worried about, that without the dust cover the pinion gears and the crown gear at the back of the scroll would get plugged with swarf quickly! So I re machined the dust cover to leave it in place with a much smaller diameter, which left lots of depth outside of that in the chucks back recces.
?Then I trepanned a recces and made a lug ring to replace the register, 1/16" deep but leaving 3/8" sticking out for the setscrews to push against.
?This ring was a light press fit into the face of the backplate and is held in place with 4 flathead socket screws from the back.
?Not difficult? to do but very effective!
?The OD of the of the ring I then turned down .015" smaller than the original register so the chuck could be adjusted. Also, the front of the ring almost touches the back of that dust cover, so no swarf can get in to the gears.


?But, (Back to the Dalton back plates) you have said in the past that Dalton threads varied in pitch diameter, maybe as taps wore? Anyway, that could make problems, right?

?Can you take a thread mic to a bunch of Dalton spindles and see how much they vary, that and the spindle's register? I'd like to have a drawing if possible, the spindles themselves would be better.