Plans for a Levin-like Steady Rest…

[tmac1956]

All:

Attached is my feeble attempt to draft a steady rest for my Levin 8mm. Let me preface this by stating flat out that I am not now, and never have been a mechanical
draftsman or engineer as I’m sure will be clear from just looking at the drawing.

My background (such as it is) is in commercial structural engineering detailing and design. With that out of the way, my idea was to use something easily obtained as stock for the tool – a 4″x3 1/2″x1/2×0′-4″ (long leg vert.) bent plate and 3/8″ steel plate and then machine it to size (based on the Levin design).

Since the steel we used was for bridges and multi-storied structures, it wasn’t very hard so I did a little digging and speced some pretty hard stuff – which is probably way harder than needed.

Anyway… perhaps one of these days I can produce something like this myself. Comment if you feel its worth your time. I might as well learn some
of the nomenclature for this type of work while I’m attempting to develop some skills.

[attachment=0:28mvxjrv]SteadyRest.pdf[/attachment:28mvxjrv]
Thanks everyone!
tmac

[david pierce]

Tom,
The drawing is excellant and very professional looking. When drawing a mechanical part it is good to keep in mind that everything in the drawing has to be made by a machinist with their available tools. For example, if a piece of 1/4″ crs has a square hole in the middle, it is less expensive and time consuming to require that the hole has rounded corners if the square hole is to be milled. Square ID corners are easier to draw but more time consuming to machine. With outside corners the opposite is true. Square outside corners are less time consuming than rounded outside corners. Tight tolerances are also expensive. If a drilled hole is good enough to make the part function properly then it should not be toleranced to .0001 inches. Different tolerances require different machining processes in order to produce a part. If you get the HF mill and begin to make the part that you drew, you will begin to rethink the design. You will ask yourself: How do I make this angle? Do I machine it out of a solid block of material? Do I take a piece of flat stock and bend it? Do I fabricate it from two pieces of flat stock? All of these issues affect the cost of the part. The only way I know to get a feel for this is to jump in with both feet and cut some metal.
david

[tmac1956]

@david pierce wrote:

Tom,
The drawing is excellant and very professional looking. When drawing a mechanical part it is good to keep in mind that everything in the drawing has to be made by a machinist with their available tools. For example, if a piece of 1/4″ crs has a square hole in the middle, it is less expensive and time consuming to require that the hole has rounded corners if the square hole is to be milled. Square ID corners are easier to draw but more time consuming to machine. With outside corners the opposite is true. Square outside corners are less time consuming than rounded outside corners. Tight tolerances are also expensive. If a drilled hole is good enough to make the part function properly then it should not be toleranced to .0001 inches. Different tolerances require different machining processes in order to produce a part.

Thanks david. When we did contract design documnts we always listened to those who did the work in the field as sometimes they could do something better and cheaper than what the engineer of record had specified in the design. So… I do understand that I have a lot to learn. Yet, this kind of commentary is super helpful for me and I really appreciate it. I’ll try to remember all of these points as I go.

@david pierce wrote:

If you get the HF mill and begin to make the part that you drew, you will begin to rethink the design. You will ask yourself: How do I make this angle? Do I machine it out of a solid block of material? Do I take a piece of flat stock and bend it? Do I fabricate it from two pieces of flat stock? All of these issues affect the cost of the part. The only way I know to get a feel for this is to jump in with both feet and cut some metal.
david

I thought about if I had that HF mill, how I could mill the bottom of that plate – or, how would I make the angled edges that fit on top of the lathe bed bar.

Regarding the grade of steel… is what I have shown even in the ball park? If you were making this part, what grade of steel would you use?
I really appreciate every you post.

Thanks,
tmac

[david pierce]

Tmac,
If it was me I would reduce it to the simplest and easiest way to manufacture the part that I knew how to do. The bottom of the device shows the tapers of the lathe bed machined into it. This would rule out cold rolled steel as it warps when machined this way. Is it necessary for the unit to lock into the bed with a precision fit the same way as a tailstock that would slide along the ways? A tailstock has to have a precision fit because there is no way to adjust anything. A steady rest has adjustable jaws meaning that aspect of the part is not necessary; so a flat plate would also work. The jaws resemble milling machine clamps. Do they require the size and strength that are specified in the design or could the same functionality be accomplished with brass set screws? Drilling and taping three holes for set screws if far less expensive than machining three slotted jaws and the slots they ride in.Also, three brass set screws will be at least as, if not more precise than, the sliding jaws. Steel is more difficult to machine than aluminum so does the part require the strength of steel or will aluminum accomplish the requirements for the loads that will be put on it? In short If it was me, I would reduce the design to the minimum cost and effort that would do the job properly.
david

[tmac1956]

@david pierce wrote:

Tmac,
If it was me I would reduce it to the simplest and easiest way to manufacture the part that I knew how to do. The bottom of the device shows the tapers of the lathe bed machined into it. This would rule out cold rolled steel as it warps when machined this way. Is it necessary for the unit to lock into the bed with a precision fit the same way as a tailstock that would slide along the ways? A tailstock has to have a precision fit because there is no way to adjust anything. A steady rest has adjustable jaws meaning that aspect of the part is not necessary; so a flat plate would also work. The jaws resemble milling machine clamps. Do they require the size and strength that are specified in the design or could the same functionality be accomplished with brass set screws? Drilling and taping three holes for set screws if far less expensive than machining three slotted jaws and the slots they ride in.Also, three brass set screws will be at least as, if not more precise than, the sliding jaws. Steel is more difficult to machine than aluminum so does the part require the strength of steel or will aluminum accomplish the requirements for the loads that will be put on it? In short If it was me, I would reduce the design to the minimum cost and effort that would do the job properly.
david

david:

That’s one of my main problems. Never having worked in a machining environment, I am ignorant of the loads placed upon such a tool on a small lathe like the Levin – and manufacturing practices. So…It sounds as though, aluminum might work in this instance. I guess I can just jump in and if it fails – it fails. It sounds like I need to back-up and re-think the design.

Synopsis:
1) Lose the slotted inteface and just go with a flat bearing surface.
2) Use aluminiunum
3) Employ a different holding scheme (perhaps use the rod system posted previously by William)

Before I begin, can you give me a good guess (for this application) on the thickness and grade of aluminum for this?

Thanks!
tmac

[david pierce]

Tom,
6061 aluminum is a good material to machine and is not horribly expensive like 2024. A 1/4 x 2 x 72 inch bar is about $30.00 and a 1 inch diameter bar of round stock is about $10.00 from MSC. There are many metal suppliers that are much cheaper than MSC but you have to hunt for them in your area. The three rod supports can be made from a length of 8-32 brass threaded rod that can also be purchased from a metal supplier or hardware store. Keep in mind that the largest diameter rod that is going to be supported and machined will probably not exceed 1/8 of an inch so design the hole to clear that (3/16-1/4). There is no need to have the front open as this is a steady rest not a follower rest. If you machine the front open it will require extra work and weaken the part. The rod supports can be located at 90 degrees, 210 degrees and 330 degrees. Since the bottom will be clear (270 degrees) a hole can be drilled and a round shaft inserted and secured with Loctite. The other end of the round shaft can be inserted into the base and also attached with Loctite. The loads on this will be extremely light due to the small size of the parts that will be machined on a WW lathe.
david

[tmac1956]

@david pierce wrote:

Tom,
6061 aluminum is a good material to machine and is not horribly expensive like 2024. A 1/4 x 2 x 72 inch bar is about $30.00 and a 1 inch diameter bar of round stock is about $10.00 from MSC. There are many metal suppliers that are much cheaper than MSC but you have to hunt for them in your area. The three rod supports can be made from a length of 8-32 brass threaded rod that can also be purchased from a metal supplier or hardware store. Keep in mind that the largest diameter rod that is going to be supported and machined will probably not exceed 1/8 of an inch so design the hole to clear that (3/16-1/4). There is no need to have the front open as this is a steady rest not a follower rest. If you machine the front open it will require extra work and weaken the part. The rod supports can be located at 90 degrees, 210 degrees and 330 degrees. Since the bottom will be clear (270 degrees) a hole can be drilled and a round shaft inserted and secured with Loctite. The other end of the round shaft can be inserted into the base and also attached with Loctite. The loads on this will be extremely light due to the small size of the parts that will be machined on a WW lathe.
david

david:

This gives something to think about.

Thanks!
tmac

[willofiam]

Hey Tmac, Great-looking drawing you’re very talented, One thing to keep in mind, And I’ve learned this over the years, Is that Something may look really good on paper but in practical application there are some issues. I would not Disregard your slots Because I think you would have a difficult time lining things up to center. Also if using this for clocks you will have a multitude of sizes of things that can get in the way, for instance a lantern pinion, or a cam or whatever, I find that the more space available for the item makes it easier to get things set up and once set up to have room to work. The one I made is nothing special but I had decided to make it as big as I could even then it can be a trick chucking up a wheel arbor and setting the steady rest in place. Just brainstorming ideas here. In the past when I would want to design something I would spend as short a time “rigging” up a prototype usually finding a change needs to be made to get what I was thinking and then refining the design as I go until finding the best way without spending a ton of time. I did this often when building furniture and would catch many unthought of issues. I can’t wait to see what you come up with, I am sure it will be something nice and Paul will have to buy me one from you. William

[willofiam]

Tmac, just this mourning I am refurbishing a clock movement, here is a couple of pics showing what I was talking about in my last post, anyway have fun, I know I am, William

p.s. Paul, I am not sure how to change photo size with this iPad, thank you.

[tmac1956]

@willofiam wrote:

Tmac, just this mourning I am refurbishing a clock movement, here is a couple of pics showing what I was talking about in my last post, anyway have fun, I know I am, William [attachment=0:dqhmr747]image.jpg[/attachment:dqhmr747][attachment=1:dqhmr747]image.jpg[/attachment:dqhmr747] Paul I am not sure how to resize photos on this iPad, sorry, thanks

Pual:

Thaks for joining the discussion and for posting the great pics – they help alot.

tmac

[tmac1956]

All.

Ok… I’ve given this some more thought (oh oh) and it would seem that I might need two of these – one like William’s design for clock repair and one for watch repair. Since William’s is already pretty cool and does the job, I’ll concentrate on the watch repair version.

Later,
tmac

[tmac1956]

David/William/et. al.:

Here is my latest attempt (based upon david’s last posting) to draft up a steady rest for watchmaking. I had to increase the center hole to 1/2″ dia. because I have big ‘ol fat fingers and I don’t think I could manipulate much with a 1/4″ dia. center hole. I found that one can buy the aluminum round stock pre-cut to 1″ at very little cost. The only thing that might be problematic is going to be the base. This is where I might have gone off of the rails. So… comments are again appreciated.

Thanks!
tmac

[attachment=0:3md6m8ax]SteadyRestSmall.pdf[/attachment:3md6m8ax]

P.s. Just so no one gets the wrong idea, I’m using AutoCad with a hand like font so there’s no talent involved in drafting this stuff up.

[david pierce]

Tom,
Do you see how much easier to build the second design will be compared to the first design. They will both do the same job which is to hold a shaft while it is turning. The most simple base I can think of is a piece of 1/4 inch x 1 1/2 inch aluminum bar stock about 2 inches long. Drill one or two holes into the bar stock to attach it to the lathe bed and have another hole to insert a 1/4 inch rod or ground dowel pin. The rod will connect the base to the round piece. The round piece will have to have a hole drilled into it to accept the rod. Loctite will hold the whole thing together with no problems if the fit is correct between the rod and the holes. This design should work well for the light loads that it will be subjected to on a watchmakers lathe.
david

[tmac1956]

@david pierce wrote:

Tom,
Do you see how much easier to build the second design will be compared to the first design. They will both do the same job which is to hold a shaft while it is turning. The most simple base I can think of is a piece of 1/4 inch x 1 1/2 inch aluminum bar stock about 2 inches long. Drill one or two holes into the bar stock to attach it to the lathe bed and have another hole to insert a 1/4 inch rod or ground dowel pin. The rod will connect the base to the round piece. The round piece will have to have a hole drilled into it to accept the rod. Loctite will hold the whole thing together with no problems if the fit is correct between the rod and the holes. This design should work well for the light loads that it will be subjected to on a watchmakers lathe.
david

david:

Thanks. I’ll give that a go.

tmac

[arutha]

David,
a friend of mine has a tool holder that has a “rest” built into it. It looks something like this –
http://www.google.co.uk/imgres?start=373&um=1&hl=en&biw=1366&bih=571&tbm=isch&tbnid=RS-vQDsMmJ5I_M:&imgrefurl=http://www.super-tech.com/root/grp.asp%3Fp1%3DTaig-Products&docid=7o8Jp0d0RknnFM&imgurl=http://www.super-tech.com/root/taig/pix/accessories/tg-1210-00.jpg&w=484&h=364&ei=tMxnUaXHEeKM0AWK_ICwDQ&zoom=1&iact=hc&vpx=143&vpy=197&dur=1641&hovh=195&hovw=259&tx=99&ty=141&page=14&tbnh=147&tbnw=185&ndsp=25&ved=1t:429,r:91,s:300,i:277

Have you seen these before?
I watched him turn a 5mm silver steel rod down to 2mm in a single pass with an almost perfect finish to the steel.
Paul.

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