Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
I believe the string was referring to ones that were all wood, like this:
Jerry F.
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Bill Williams
12:18pm? ?
I believe Martin Evans did one of these documented in "The Model Engineer" about 50 years ago.
It will work on few threads. Example? Lead screw with 8TPI It will work on 8, 16, 24 , 32 , 40 and 48 TPI THREAD cutting.?? In metric leadscrew 2mm It will work on 2mm, 1 mm and .5mm I can do that with a dog clutch just by using the haft nut. Dave?
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I believe Martin Evans did one of these documented in "The Model Engineer" about 50 years ago. His had an automatic tool retract and second clutch for a double speed return! Like a Hardinge production but DIY!? ?Bill in Boulder
On Sun, Jan 28, 2024 at 11:06?AM davesmith1800 < davesmith1@...> wrote: The CGTK dog clutch is shown here:
At end page he remove the clutch.
Also have program to calculate for threading dials.
Dave?
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
like these ?
thanks
animal
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On 1/28/24 12:01 PM, David Wiseman wrote: They are of the style of an engineers hand clamp but really HUGE in comparison and of course made of wood.
Best regards
David
On 28 Jan 2024, at 19:01, mike allen <animal@...> wrote:
?Are these clamps the " hand screw " clamps ? They have left & right hand
threads . I've never seen a set with wooden screws .
animal
On 1/15/24 11:39 PM, DAVID WILLIAMS via groups.io wrote:
Dear All,
I realise this is both part Mini lathe and part wood lathe. But to me the metal lathe part is more important. Hence my question to you all.
I have a couple of these old wooden clamps - probably antique. They are just like the metalwork ones we use, but much much larger. One has a severely damaged (external) threads.
I would like to try(?) and cut the replacement long wooden thread on my 7 x 12. So, I bought a second hand thread chaser on eBay. It¡¯s 6 TPI and according to the chart on the Little Machine Shop site - the gear set up is no problem on my imperial lathe.
[JFI it¡¯s Real Bull model purchased from Chester Machines (in the UK) some 20+ years ago. If that¡¯s at all relevant?]
The thread chaser cuts multiple threads at the same time and the tool (normally hand held I understand) needs to be held at ~ 90 degrees to the thread, unlike the usual angle for cutting one side of a metal thread. OR, if you are doing it by hand, do you angle the thread chaser so it cuts a series of slightly deeper threads. Thus the tool needs to be held in the tool post at a similar angle?
Assuming I can sharpen it correctly and clamp it to the tool post, can anyone offer any suggestions or guidance? Do you cut it in multiple passes, in a similar way to a metal thread?
I assume I¡¯m going to have to make and use some sort of a travelling steady. My idea is to clamp it in the chuck and use a small freely rotating chuck at the tailstock end.
I believe I can get a much better quality and accurate thread using the gears than trying to use it hand held - on a very long tool holder, the same as the ones on a wood lathe. I have to check but I think the wood for the screws is normally Beech, if that¡¯s relevant?
Thank you in anticipation.
David of Abingdon(UK)
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
They are of the style of an engineers hand clamp but really HUGE in comparison and of course made of wood.
Best regards
David
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Show quoted text
On 28 Jan 2024, at 19:01, mike allen <animal@...> wrote:
?Are these clamps the " hand screw " clamps ? They have left & right hand
threads . I've never seen a set with wooden screws .
animal
On 1/15/24 11:39 PM, DAVID WILLIAMS via groups.io wrote:
Dear All,
I realise this is both part Mini lathe and part wood lathe. But to me the metal lathe part is more important. Hence my question to you all.
I have a couple of these old wooden clamps - probably antique. They are just like the metalwork ones we use, but much much larger. One has a severely damaged (external) threads.
I would like to try(?) and cut the replacement long wooden thread on my 7 x 12. So, I bought a second hand thread chaser on eBay. It¡¯s 6 TPI and according to the chart on the Little Machine Shop site - the gear set up is no problem on my imperial lathe.
[JFI it¡¯s Real Bull model purchased from Chester Machines (in the UK) some 20+ years ago. If that¡¯s at all relevant?]
The thread chaser cuts multiple threads at the same time and the tool (normally hand held I understand) needs to be held at ~ 90 degrees to the thread, unlike the usual angle for cutting one side of a metal thread. OR, if you are doing it by hand, do you angle the thread chaser so it cuts a series of slightly deeper threads. Thus the tool needs to be held in the tool post at a similar angle?
Assuming I can sharpen it correctly and clamp it to the tool post, can anyone offer any suggestions or guidance? Do you cut it in multiple passes, in a similar way to a metal thread?
I assume I¡¯m going to have to make and use some sort of a travelling steady. My idea is to clamp it in the chuck and use a small freely rotating chuck at the tailstock end.
I believe I can get a much better quality and accurate thread using the gears than trying to use it hand held - on a very long tool holder, the same as the ones on a wood lathe. I have to check but I think the wood for the screws is normally Beech, if that¡¯s relevant?
Thank you in anticipation.
David of Abingdon(UK)
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
Are these clamps the " hand screw " clamps ? They have left & right hand
threads . I've never seen a set with wooden screws .
??? animal
toggle quoted message
Show quoted text
On 1/15/24 11:39 PM, DAVID WILLIAMS via groups.io wrote: Dear All,
I realise this is both part Mini lathe and part wood lathe. But to me the metal lathe part is more important. Hence my question to you all.
I have a couple of these old wooden clamps - probably antique. They are just like the metalwork ones we use, but much much larger. One has a severely damaged (external) threads.
I would like to try(?) and cut the replacement long wooden thread on my 7 x 12. So, I bought a second hand thread chaser on eBay. It¡¯s 6 TPI and according to the chart on the Little Machine Shop site - the gear set up is no problem on my imperial lathe.
[JFI it¡¯s Real Bull model purchased from Chester Machines (in the UK) some 20+ years ago. If that¡¯s at all relevant?]
The thread chaser cuts multiple threads at the same time and the tool (normally hand held I understand) needs to be held at ~ 90 degrees to the thread, unlike the usual angle for cutting one side of a metal thread. OR, if you are doing it by hand, do you angle the thread chaser so it cuts a series of slightly deeper threads. Thus the tool needs to be held in the tool post at a similar angle?
Assuming I can sharpen it correctly and clamp it to the tool post, can anyone offer any suggestions or guidance? Do you cut it in multiple passes, in a similar way to a metal thread?
I assume I¡¯m going to have to make and use some sort of a travelling steady. My idea is to clamp it in the chuck and use a small freely rotating chuck at the tailstock end.
I believe I can get a much better quality and accurate thread using the gears than trying to use it hand held - on a very long tool holder, the same as the ones on a wood lathe. I have to check but I think the wood for the screws is normally Beech, if that¡¯s relevant?
Thank you in anticipation.
David of Abingdon(UK)
|
The CGTK dog clutch is shown here:
At end page he remove the clutch. Also have program to calculate for threading dials. Dave?
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
When doing wood use a light bedway oil.?
Wipe off every hour.
I use metal lathes for wood foundry patterns since 1960's.?
Never had a wood lathe
Dave?
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A dog clutch is used for threading in a number of high end lathes e.g. the Hardinge HLV-H.
The CGTK dog clutch is shown here:?
CGTK copied it from my site but it looks like he mis-understood how to engage the clutch which likely led to it failing.? Compare the first picture on my site:? ? to the first picture on the CGTK site and notice the spring on the rod which engages the clutch. This is missing on CGTK's version - this spring is important since it allows minimal force to be applied to the clutch while waiting for the spindle to rotate into position for the dog to engage.? Applying the full force of the trigger directly to the clutch likely caused the engagement mechanism to fail.? My dog clutch has not failed in the 15 years it has been in place, although it does need oiling every 3 or 4 years else it becomes slow to engage.
There is nothing wrong with using a thread dial for imperial or metric threading. But the original poster seemed to be preparing to build a metric thread dial which needs 3 interchangeable gears to cover all metric threads.? My point was that a dog clutch is relatively easy to build compared to cutting gears and making the numbered dial and the associated holder.? Plus the dog clutch works for imperial and metric. And it picks up the thread in one spindle rotation, no waiting for the dial to come around.
John
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
How do you keep from getting sawdust all over your oily ways, and every other part of the lathe with an oily film (i.e., all of it)?
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Re: New topic ¡ª- Cutting a thread for a very old wooden clamp.
If you haven't cut your thread already...
As a woodworker and machinist, I have used my metal lathe for wood parts fairly frequently.? If the threads are Acme or similar, think about mounting a Dremel (type) tool with a bit to cut the bulk of your threads before following with the chaser. Or a custom ground HSS bit or cutoff tool much narrower than the thread width to avoid grain tearout. You have to be extremely careful with a full dimension form tool with most woods at that grain orientation. If your wood is at all porous (lignum vitae wouldn't qualify) consider saturating the thread dowel with CPES, either commercial or thinning your own epoxy about 10% with alcohol. It will make the threads stronger and slipperier.
Joe
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Re: Direct Reading cross feed dial.
Here is direct reading for a lathes in DRO'S.
To big for mini lathes.
Only for information.?
I found dials are far better as you do not loose capacity with dials.
Dave?
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Re: Direct Reading cross feed dial.
Doesn't the acceptable error depend on the length of engagement between the male and female parts?
Ralphie?
On Sat, Jan 27, 2024, 4:14 PM Charles Kinzer < ckinzer@...> wrote:
I find numerous problems with the scheme of moving both handwheels like that for the purpose of making a 29.5 degree vector.? That's all that is happening.? Two vectors at right angles combining to produce a vector at an angle.
First, the standard way doesn't require any trig at all.? You simply view the compound dial as direct reading.? Of course, this is an approximation because the sine of 30 degrees is 0.5 which would relate to exactly a direct reading.? the sine of 29.5 degrees is0.4924 so, technically, there will be an error.? But it is so small that it is typically ignored.? For example, if you had a 0.100 thread depth (pretty big thread in the mini lathe world at least) you get 0.0985" thread depth or a 1.5 thousandths error which is going to be within pretty much anybody's spec for a thread like that.? For typical smaller threads the error is in tenths because the error is about 1.5%.? How much absolute error is that for a 10-32?
Second, the primary purpose of the 29.5 degree compound is to have most of the cutting done on one edge and the other just as a skim cut.? By using the cross slide as part of creating the vector, that goal is substantially degraded as there will be too much cutting on the right edge (for typical right to left threading).? Since the scheme violates the primary goal, anyway, why not just go straight in and be done with it.
Third, you have to accurately set NEW positions on two handwheels.? That certainly increases the exposure for an error and a spoiled part.? Machinists typically don't want to do things a hard way when there is an easier one.
Charles E. "Chuck" Kinzer
On Saturday, January 27, 2024 at 11:17:39 AM PST, davesmith1800 < davesmith1@...> wrote:
Take a sharpie and cross out the numbers on your dial, then double them and write the new numbers in.
?
Brian?
Sharpie may last 30 seconds. I like the look of manufacture type dial. My second lathe had most of marks worn off and I used a center punch to fix it look tacky Dave?? Dave?
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Johannes 5:44pm? ?
CGTK.CO.UK made this dog clutch, however, in is web page he said this:
Update - Dog Clutch Removed
I used haft nut and threading dial most lfe. This first time in metric lead screw . See nothing wrong a threading dial.? Dave?
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CGTK.CO.UK ?made this dog clutch, however, in is web page he said this: Update - Dog Clutch RemovedAbout a year or so after building and fitting the dog clutch, I finally removed it from the mini-lathe. Due to the small size of the components in the clutch itself, it had needed repair a couple of times in that period. Also in that period I'd found a much better way of threading. I now do almost all of my threading with the tool mounted upside-down in the tool-post and the lathe running backwards (don't do this if you have a threaded chuck mount). In this configuration, the tool is moving away from the headstock as it cuts and you have all the time you need to disengage the leadscrew when the tool has run off the end of the workpiece. Johannes ? Lavoll. ? ? ? ? ? ? ?
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On 27 Jan 2024, at 18:53, Bill Williams <BWMSBLDR1@...> wrote:
? A one tooth dog clutch on the spindle.? ?Bill On Sat, Jan 27, 2024 at 11:32?AM davesmith1800 < davesmith1@...> wrote:
Rather than building a thread dial for metric threading (needs multiple gears) you might consider building a dog clutch - it works for imperial and metric, eliminating the thread dial.? You can manually operate the dog clutch or build an auto-stop for it.
I have look dog clutch but I have never seen any manufacture use a dog clutch.
Even the automatic type still used a gear on the screw for engagement of haft nut.
Dave
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Neat!
Do you know if there's a site that has any of the other service bulletins?
Roy
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Re: Extension cross slide
Here the screw being thread?  Finish?  In the lathe ready for other end to be turned?  Dave?
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A one tooth dog clutch on the spindle.? ?Bill
On Sat, Jan 27, 2024 at 11:32?AM davesmith1800 < davesmith1@...> wrote:
Rather than building a thread dial for metric threading (needs multiple gears) you might consider building a dog clutch - it works for imperial and metric, eliminating the thread dial.? You can manually operate the dog clutch or build an auto-stop for it.
I have look dog clutch but I have never seen any manufacture use a dog clutch.
Even the automatic type still used a gear on the screw for engagement of haft nut.
Dave
|
Re: Direct Reading cross feed dial.
I find numerous problems with the scheme of moving both handwheels like that for the purpose of making a 29.5 degree vector.? That's all that is happening.? Two vectors at right angles combining to produce a vector at an angle.
First, the standard way doesn't require any trig at all.? You simply view the compound dial as direct reading.? Of course, this is an approximation because the sine of 30 degrees is 0.5 which would relate to exactly a direct reading.? the sine of 29.5 degrees is0.4924 so, technically, there will be an error.? But it is so small that it is typically ignored.? For example, if you had a 0.100 thread depth (pretty big thread in the mini lathe world at least) you get 0.0985" thread depth or a 1.5 thousandths error which is going to be within pretty much anybody's spec for a thread like that.? For typical smaller threads the error is in tenths because the error is about 1.5%.? How much absolute error is that for a 10-32?
Second, the primary purpose of the 29.5 degree compound is to have most of the cutting done on one edge and the other just as a skim cut.? By using the cross slide as part of creating the vector, that goal is substantially degraded as there will be too much cutting on the right edge (for typical right to left threading).? Since the scheme violates the primary goal, anyway, why not just go straight in and be done with it.
Third, you have to accurately set NEW positions on two handwheels.? That certainly increases the exposure for an error and a spoiled part.? Machinists typically don't want to do things a hard way when there is an easier one.
Charles E. "Chuck" Kinzer
On Saturday, January 27, 2024 at 11:17:39 AM PST, davesmith1800 <davesmith1@...> wrote:
Take a sharpie and cross out the numbers on your dial, then double them and write the new numbers in.
?
Brian?
Sharpie may last 30 seconds. I like the look of manufacture type dial. My second lathe had most of marks worn off and I used a center punch to fix it look tacky Dave?? Dave?
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??? ??? Thanks , that interestin . I have never seen a red one in
the wild .
??? animal
On 1/27/24 2:25 PM, Jon Rus via
groups.io wrote:
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At the bottom of page 14, Bulletin
33-j, it says you can order RED
or Grey as
your color....
On 1/27/2024 2:16 PM, mike allen
wrote:
Craftsman sold a Lathe setup fro doing armatures , hey come
up every once in a while on ebay . Had a jacobs chuck that
screwed on the spindle , a Jacobs chuck live center I believe
, a Mica undercutter & sopme misc parts .
I found 2 South Bend Lathe co publications on Armature work
its interesting that they made the lathe
look
red on one of the
SB publications , my TruCut armature lathe is red .
animal
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davesmith1800
GadgetBuilder
Ralph Lehotsky
Johannes
?GadgetBuilder?