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Re: First attempts - finish on brass (all?)
Another option might be a sheering tool; I've used them on steel with great results, but never tried brass.? Has anyone? -Dave
On Sunday, April 19, 2020, 01:43:40 AM PDT, William Ayerst <willayerst@...> wrote:
Hello there chaps,
After the kind advice to try out a cannon and the location of the Edenstaal plans on the files part of this group, I thought I¡¯d test out the lathe again after a period of hibernation. I am using a Unimat SL. The tool that came with the lathe was 1/4¡± HSS, so I have replaced this with a 6mm set from RDGTools (and after some experimentation, a 0.31mm shim underneath the tool, to return it to the height of a 1/4¡± tool). Now, using a left-handed cutting/facing tool I can cut across the diameter of a rod and get no ¡®pip¡¯. If I use a parting off fool, I get chips and very small curls of brass appearing, instead of chatter/etc. I wanted to experiment with getting a good surface finish, so I am using a straight turning tool, as I understand it: (Type-3 ST Turning) This is the result: The leftmost section has been polished with some emery paper while in the lathe, the right hand side is au naturel If this is as good as I can expect, then that¡¯s fine - but I¡¯m going with as fine a cut as I can (the smallest subdivision on the cross slide) and as slow as seems reasonable (1-2mm per second longitudinally. If anyone could give me some guidance as to what I¡¯m doing wrong - or what I need to do differently, I would greatly appreciate it. Many thanks, |
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Re: Cap for coil/spring assembly
¿ªÔÆÌåÓýHello
Lars: Do you mean the cupped washer that holds the coil spring that retracts the quill? I took mind off years ago to have 25mm of quill travel instead of 19mm. Of course you could machine a new one, you have a Unimat! Two options: 1) Turn from the solid. 2) Use sheet aluminum and roll the edge of the cup. Best
wishes, Carl. On 4/18/2020 12:55 PM,
hakanssondahlberg@... wrote:
Hi, |
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Re: First attempts - finish on brass (all?)
¿ªÔÆÌåÓýHi Gang: I used my Erector set motor for power feed once. The transmission allowed 2 speeds, forward and reverse. Plus since it drove the hex nut holding the hand wheel on it could drive all three hand wheels, carriage, cross feed and the tailstock! But since I don't mind turning the knobs I never use it. Carl. On 4/19/2020 8:50 AM, Martin P. via
groups.io wrote:
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Re: First attempts - finish on brass (all?)
Hi William,
On the subject of cutting tools, have you considered learning to grind your own tools? Adding this skill to your ¡°tool box¡± will enable you to grind any shape you will ever need not to mention the cost savings. Also consider using smaller tools such as 3/16¡± square. They require less metal removal and are therefore quicker to grind and regrind. Dick |
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Re: First attempts - finish on brass (all?)
¿ªÔÆÌåÓýIt also occurred to me that you said you were using a left handed tool. ? If you are turning with the tool moving towards the headstock (which is the more usual situation) then you should use a right handed tool. LH is for cutting away from the headstock, usually up to a shoulder. ? Regards, Andy ? From: [email protected] [mailto:[email protected]] On Behalf Of Andy Carlson
Sent: 19 April 2020 11:52 To: [email protected]; willayerst@... Subject: Re: [Unimat] First attempts - finish on brass (all?) ? Strictly speaking brass needs no, or a slight negative rake on the tool. This removes the tendency for the tool to dig in. ? I guess that most of these general purpose packs are ground with rake angles for steel so that probably isn¡¯t helping. ? In practice I mostly use the same tools on brass and steel though, but most are ones I¡¯ve ground myself and don¡¯t (for example) have that ¡®trough¡¯ that you see on the off the shelf tool. ? If you can grind your own tools from blanks then grinding a simple knife tool is straightforward enough ¨C it¡¯s parting, boring and thread cutting ones that are difficult. ? Regards, Andy ? From: [email protected] [mailto:[email protected]] On Behalf Of William Ayerst ? Hello there chaps, ? After the kind advice to try out a cannon and the location of the Edenstaal plans on the files part of this group, I thought I¡¯d test out the lathe again after a period of hibernation. ? I am using a Unimat SL. The tool that came with the lathe was 1/4¡± HSS, so I have replaced this with a 6mm set from RDGTools (and after some experimentation, a 0.31mm shim underneath the tool, to return it to the height of a 1/4¡± tool). Now, using a left-handed cutting/facing tool I can cut across the diameter of a rod and get no ¡®pip¡¯. If I use a parting off fool, I get chips and very small curls of brass appearing, instead of chatter/etc. ? I wanted to experiment with getting a good surface finish, so I am using a straight turning tool, as I understand it: ? (Type-3 ST Turning) ? This is the result: The leftmost section has been polished with some emery paper while in the lathe, the right hand side is au naturel ? If this is as good as I can expect, then that¡¯s fine - but I¡¯m going with as fine a cut as I can (the smallest subdivision on the cross slide) and as slow as seems reasonable (1-2mm per second longitudinally. ? If anyone could give me some guidance as to what I¡¯m doing wrong - or what I need to do differently, I would greatly appreciate it. ? Many thanks, ? |
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Re: First attempts - finish on brass (all?)
¿ªÔÆÌåÓýStrictly speaking brass needs no, or a slight negative rake on the tool. This removes the tendency for the tool to dig in. ? I guess that most of these general purpose packs are ground with rake angles for steel so that probably isn¡¯t helping. ? In practice I mostly use the same tools on brass and steel though, but most are ones I¡¯ve ground myself and don¡¯t (for example) have that ¡®trough¡¯ that you see on the off the shelf tool. ? If you can grind your own tools from blanks then grinding a simple knife tool is straightforward enough ¨C it¡¯s parting, boring and thread cutting ones that are difficult. ? Regards, Andy ? From: [email protected] [mailto:[email protected]] On Behalf Of William Ayerst
Sent: 19 April 2020 09:43 To: [email protected] Subject: [Unimat] First attempts - finish on brass (all?) ? Hello there chaps, ? After the kind advice to try out a cannon and the location of the Edenstaal plans on the files part of this group, I thought I¡¯d test out the lathe again after a period of hibernation. ? I am using a Unimat SL. The tool that came with the lathe was 1/4¡± HSS, so I have replaced this with a 6mm set from RDGTools (and after some experimentation, a 0.31mm shim underneath the tool, to return it to the height of a 1/4¡± tool). Now, using a left-handed cutting/facing tool I can cut across the diameter of a rod and get no ¡®pip¡¯. If I use a parting off fool, I get chips and very small curls of brass appearing, instead of chatter/etc. ? I wanted to experiment with getting a good surface finish, so I am using a straight turning tool, as I understand it: ? (Type-3 ST Turning) ? This is the result: The leftmost section has been polished with some emery paper while in the lathe, the right hand side is au naturel ? If this is as good as I can expect, then that¡¯s fine - but I¡¯m going with as fine a cut as I can (the smallest subdivision on the cross slide) and as slow as seems reasonable (1-2mm per second longitudinally. ? If anyone could give me some guidance as to what I¡¯m doing wrong - or what I need to do differently, I would greatly appreciate it. ? Many thanks, ? |
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Re: First attempts - finish on brass (all?)
This is one of my test pieces straight from the lathe, it was mostly cut with a standard straight cut tool as shown in the second picture.
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Sent from my Huawei tablet -------- Original Message -------- Subject: [Unimat] First attempts - finish on brass (all?) From: William Ayerst To: [email protected] CC: Hello there chaps, |
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Re: First attempts - finish on brass (all?)
For brass a round nose bit will give a smooth surface, with a pointed tool it's like you are cutting a thread.
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Sent from my Huawei tablet -------- Original Message -------- Subject: [Unimat] First attempts - finish on brass (all?) From: William Ayerst To: [email protected] CC: Hello there chaps, |
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First attempts - finish on brass (all?)
William Ayerst
¿ªÔÆÌåÓýHello there chaps,After the kind advice to try out a cannon and the location of the Edenstaal plans on the files part of this group, I thought I¡¯d test out the lathe again after a period of hibernation. I am using a Unimat SL. The tool that came with the lathe was 1/4¡± HSS, so I have replaced this with a 6mm set from RDGTools (and after some experimentation, a 0.31mm shim underneath the tool, to return it to the height of a 1/4¡± tool). Now, using a left-handed cutting/facing tool I can cut across the diameter of a rod and get no ¡®pip¡¯. If I use a parting off fool, I get chips and very small curls of brass appearing, instead of chatter/etc. I wanted to experiment with getting a good surface finish, so I am using a straight turning tool, as I understand it: (Type-3 ST Turning) This is the result: The leftmost section has been polished with some emery paper while in the lathe, the right hand side is au naturel If this is as good as I can expect, then that¡¯s fine - but I¡¯m going with as fine a cut as I can (the smallest subdivision on the cross slide) and as slow as seems reasonable (1-2mm per second longitudinally. If anyone could give me some guidance as to what I¡¯m doing wrong - or what I need to do differently, I would greatly appreciate it. Many thanks, |
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Re: 'Exercises' for learning the unimat
?I thought the original Unimat steam engine project could be a good all-round learning and/or re-skilling project, so I found some info on Youtube:?I¡¯ll start it one of these days - I¡¯m also at the messing-around phase with my lathe, which has been about 5 years so far, and have made a model railroad part or two. Messing around isn¡¯t wasting time or material - it¡¯s sharpening your skills and learning the machine¡¯s limitations too. Have fun!Dave W I dont suppose you have the plans for the miniature steam engine do you? The one by Leslie Proper?? |
Carl
OldToolmaker
Unimat Matt
