# Making A Dovetail Slide



## savarin (Sep 11, 2016)

For my vertical slide I was going to use box slides like the gingery versions.
Last night I had a brain fart and wondered if it would be possible to make an assembled dovetail by milling a 45' chamfer on a bar that can be bolted to the main plate (one on each side) then mill the same chamfer down both sides of the slide plate to fit between them. This would be easier than using a dovetail cutter.
Gibs can be added as required.
Anyone see why this wouldnt work?


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## Bob Korves (Sep 11, 2016)

Sounds good to me, just need to get it bolted down really solidly and with sliding surfaces parallel.  Ditto on parallel for the slide plate sliding surfaces.


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## JimDawson (Sep 11, 2016)

Should work fine.


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## Eddyde (Sep 11, 2016)

Don't see why not, though I'm sure there will be some unforeseen hurdles along the way.


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## Tony Wells (Sep 11, 2016)

Once you have everything aligned and moving as you want, I'd recommend a couple of dowel pins on each side to ensure that they don't move relative to each other or the base plate. This would better simulate machining it from a solid piece. Take the time to polish by lapping the bearing surfaces and then either flake it or cut some oil grooves in it, not the moving part, but the fixed part. On the side that will get the gib, put the oil grooves in the contact side of the gib, and drill through some oil holes that break into the oil grooves. You must find a way to keep a film of oil in the contact areas.


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## savarin (Sep 12, 2016)

Thanks guys, I like the idea of the dowel pins as well.
Pity it isnt made yet as they will be easier to machine on the new version. I will just have to take it slow.


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## Billh50 (Sep 12, 2016)

Tony is right about doweling. I made a small slide years ago like that. The rails can move if they are not doweled. Rough drill the dowel holes. Align everything  for a good fit and tighten screws. Then ream the dowel holes. You should be good to go.


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## savarin (Sep 12, 2016)

thanks, had a test at using a carbide woodworking router bit to try and cut the chamfer.
It broke.
It will all have to wait for a couple of weeks now as I'm off to Japan Friday.


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## benmychree (Jun 1, 2017)

As to the angle, 45 degrees is uncommon for dovetails, the standard being 60 deg., which gives a more open and easier to scrape dovetail and the male part does not get so pinched down at its base, leaving more room for a lead screw.


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## savarin (Jun 1, 2017)

Thanks Benny, thats what I eventually used.
The finished item is here if interested.
http://www.hobby-machinist.com/threads/a-vertical-slide-for-a-9x20-lathe.49724/


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## Jimsehr (Jun 2, 2017)

I made a tool.to cut tapers ten years ago. And I used dovetailed pieces like that. I used dowels to lock them in place. My Logan has a production cross slide on it and the tool I made is like compound slide kind of like a sine bar. It has about 5 or 6 inches of travel and I used a piece of allthread for a leadscrew. With the tool I have cut tapered tooling for my Logan and Rockwell lathes. I made the tool so that after I have cut the taper I want , I drill and ream a hole thru both the bottom and top plate
Then mark the hole so that if I need that taper again I just pin the marked hole and I can recut that taper again. So I have marked the Logan taper and the Rockwell taper and the Morse tapers. If you want to see tool google   Jimsehrs taper slide tool.
Jimsehr


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## samthedog (Jun 2, 2017)

Tony Wells said:


> Once you have everything aligned and moving as you want, I'd recommend a couple of dowel pins on each side to ensure that they don't move relative to each other or the base plate. This would better simulate machining it from a solid piece. Take the time to polish by lapping the bearing surfaces and then either flake it or cut some oil grooves in it, not the moving part, but the fixed part. On the side that will get the gib, put the oil grooves in the contact side of the gib, and drill through some oil holes that break into the oil grooves. You must find a way to keep a film of oil in the contact areas.



On the Clarkson tool and cutter grinder there is no means to oil the sliding surfaces at all. One of the reasons they did this is because the oiled surface attracts the grinding dust. I have a clarkson grinder from the early 70's and despite the leadscrew having some slop, the sliding surfaces are still ok. It was assumed that the cast iron would be lubricitous enough that oil would not be needed. I know that oil is always better but in this application the engineers chose against having oiled surfaces. I would probably opt for a dry lubricant on a tool and cutter grinder if given the choice.

On a lathe cross slide I would certainly opt for having the solution you mentioned. I would just make sure that the flaking and the oil grooves were on the under side to ensure no swarf or cast iron dust would ever get caught and create lapping compund.

Paul.


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## Bob Korves (Jun 2, 2017)

Industrial grinders and surface grinders have oiled ways and/or rollers for longer life with much more table motion than tool and cutter grinders.  They often use fairly elaborate and multiple means to try to keep the grit out of the oil.


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## 4GSR (Jun 2, 2017)

Even my K O Lee tool & cutter grinder has oil lubricated ways on it.  The ways are covered very good to keep most grinding dust out.  The cross feed and elevation screws are trashed from the lack of lubrication and collection of grinding dust to wear them out.


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## tertiaryjim (Jun 3, 2017)

I'm currently working on a Delta Milwaukee grinder that was so abused I've had to machine 6 to 12 thousanths from the way surfaces prior to scraping.
The screws and nuts are troubled or trashed...........
Had the prior owners kept the machine properly clean and lubricated IE "followed the instructions" it would have been a different story.
The base is too big for me to machine so I've had to scrape about 6 thousanths to get below the scores.
Now I notice how the cast iron on cast iron with just blue for lube, slide better as I increase the contact area.
Will have to make a hand plane to cut the slide surfaces true as I don't have machine capacity for them.
That means a tool that will need rigidity and a couple of dovetails.
It's interesting and helpful to see how others deal with design.


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