Cross slide and compound dials

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Mr Ron
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Cross slide and compound dials

Post by Mr Ron »

Previously I had posted a question about making new dials for the cross slide and compound dials. I was directed to a you tube video of someone making them. That was very informative except the video showed how to make dials with 100 divisions, each division representing .001". Great, except the dials on my lathe have 125 divisions. Lacking a dividing head, I cannot divide 125. It shouldn't matter how many divisions are on the dial; right! Can I just use a 100 division dial instead of the 125 dial? As it stands now, one revolution of the dial advances the slide 0.125". If I make a dial with 100 divisions, then one revolution of the dial will advance the slide 0.100". Would that create a problem?
Mr.Ron from South Mississippi
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GlennW
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Re: Cross slide and compound dials

Post by GlennW »

Mr Ron wrote: Mon Apr 02, 2018 5:34 pm As it stands now, one revolution of the dial advances the slide 0.125". If I make a dial with 100 divisions, then one revolution of the dial will advance the slide 0.100". Would that create a problem?
What will happen is that one revolution of the dial will be 100 graduations, but it will still advance the slide .125". (100 graduations would advance the slide .00125" per graduation)

Another explanation may hide in the old pizza joke. "Better cut it into six pieces, I don't think I could eat eight!"
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ctwo
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Re: Cross slide and compound dials

Post by ctwo »

How were you going to make 100 graduations without a dividing head? I'm sure there is a way for you to get 125 graduations.
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Mr Ron
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Re: Cross slide and compound dials

Post by Mr Ron »

ctwo wrote: Tue Apr 03, 2018 11:27 am How were you going to make 100 graduations without a dividing head? I'm sure there is a way for you to get 125 graduations.
There was a video showing a dial with 100 divisions being made using a 100 tooth circular saw blade as an indexer. I can't find anything that has 125 teeth (divisions) on it.
Mr.Ron from South Mississippi
Mr Ron
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Re: Cross slide and compound dials

Post by Mr Ron »

GlennW wrote: Mon Apr 02, 2018 6:02 pm What will happen is that one revolution of the dial will be 100 graduations, but it will still advance the slide .125". (100 graduations would advance the slide .00125" per graduation)
You are correct. I will have to use 125 divisions.
Mr.Ron from South Mississippi
SteveM
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Re: Cross slide and compound dials

Post by SteveM »

If you could find a 125 tooth gear, that would do it, but a search of ebay only comes up with one hit and it was pretty expensive.

If you have a friend with a dividing head, he can just cut 125 notches into a circular piece of sheet metal.

Another option is to look for a replacement dial on ebay and bore or sleeve the hole to match yours.

Steve
Mr Ron
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Re: Cross slide and compound dials

Post by Mr Ron »

I racked my brain trying to find anything with 125 divisions and came up zip. One suggestion I got was to use a piece of a bandsaw blade with maybe 8 teeth per inch; roll it into a loop with 125 teeth. Sounds like the only option I have.
Mr.Ron from South Mississippi
Inspector
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Re: Cross slide and compound dials

Post by Inspector »

I just searched 125 tooth gear and the first that popped up was. http://www.revrobotics.com/rev-41-1333/

Here is one more for less.
https://www.ebay.com/itm/Robinson-Racin ... 2292803016
Last edited by Inspector on Wed Apr 04, 2018 11:09 am, edited 1 time in total.
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BadDog
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Re: Cross slide and compound dials

Post by BadDog »

I saw a lot of good ideas (including the band saw blade indexer IIRC) in Lautard's Bedside Reader books. I really enjoyed and learned a lot from those when I was was struggling to get things sorted out in this hobby to suite my needs. There is quite a lot of stuff in there about how to manage without having all the ideal toys.
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prjones3
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Re: Cross slide and compound dials

Post by prjones3 »

You can use an inexpensive 125 tooth gear such as one made by Rev Robotics ( $7 and see http://www.revrobotics.com/rev-41-1333/ ) as a template and used a homemade indent to do the tooth selection on the back end of the lathe headstock and scribe with a very sharp tool while while the dial blank is held in the lathe chuck.
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SteveHGraham
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Re: Cross slide and compound dials

Post by SteveHGraham »

Clockmaker W.R. Smith does a lot of nutty indexing with his lathe. He fits a large wheel (wood or MDF, I guess) around the spindle. The wheel has holes drilled in it; however many divisions you want. A flexible bar is affixed to the headstock, and on the other end, it has a pin to fit the holes. You put the wheel where you want it, put the pin in a hole to hold it in place, and drill or cut whatever you have held in the chuck. The cutting tool goes on the carriage. It would also work for making divisions.

You would just need a kind soul to make you a wheel that will fit your lathe.

I saw him do this with a huge wheel. I think the benefit was that a large wheel would produce smaller angular errors. He mounted a tape measure on the perimeter of the wheel. Can't recall how he used it. He has wonderful DVD's.

I see there are a bunch of lathe indexing videos on Youtube. He may have inspired them.
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John Hasler
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Re: Cross slide and compound dials

Post by John Hasler »

prjones3 wrote: Fri Apr 06, 2018 10:17 am You can use an inexpensive 125 tooth gear such as one made by Rev Robotics ( $7 and see http://www.revrobotics.com/rev-41-1333/ ) as a template and used a homemade indent to do the tooth selection on the back end of the lathe headstock and scribe with a very sharp tool while while the dial blank is held in the lathe chuck.
I've done exactly this (but not 125 teeth) using the change gears for my lathe. Works a treat.
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