Tips on machining pulley grooves
As part of my 24v re-motoring exercise I’m making new pulleys from aluminium. I’m not finding it easy to machine the groove for the belt and would appreciate any tips (apart from ‘buy them online’ and ‘do it on a bigger lathe’ - I just have the U3).
I use ‘O’ rings for belts, they have a 5mm cross-section diameter. The finished inner diameter at the bottom of the groove will be 38mm. The pulley body is 9mm thick to allow for the flange portions either side of the groove.
For a cutter I first tried a 6mm drill bit cut off at 45 degrees and then milled clean. Blimey a drill bit is hard to saw with a hacksaw. Two blades later… the endmill had no problem however. ?The finished ‘cutter’ didn’t cut very well though.
Next I ground a cutter (my first!) from a 6mm blank. Semi-circular, with a 6 degree angle, and some top relief (as recommended for aluminium I believe). This was moderately successful but it is doing more of a scrape than a cut. It is literally ‘stop start’. It did however produce some beautiful swarf, almost like snowflakes, or frost.
It is making pulleys - but painfully slowly. I have more material to remove and it is not working well at the moment.
I think I should be taking out excess material in smaller chunks first then finishing with the shaped tool, but a plan to do this is puzzling me given the finished shape. It’s taken a long time to get this far from a large chunk of aluminium and I don’t want to ruin anything!
So far I’m going in at one position. I did wonder if alternating cuts between two slightly altered positions (kind of left and right) would be beneficial - the cutter would (or might) only be using 50% of the cutting edge.
I’m making three pulleys in all - one for the motor and one each for the lathe and mill.
As usual I have very little idea what I’m doing so am looking to tap into folks wealth of knowledge and experience. Any tips gratefully received. Thanks!
(Sorry for the overlong post - the quick version would be ‘How would you make a pulley groove?’ :-)
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Hello:
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On Sat, Sep 16, 2023 at 03:42 PM, Peter Brooks wrote:
... thanks for that and for the link to the post on ME.
You're welcome, hope it was at least it gave you an idea as to where you stand.
... glad I’m not the only one to notice ...
Make no mistake: everyone who comes across the problem notices it as it is a nightmare to try to turn even a small part properly. What was hard/impossible to find was the actual cause. Easily traced to the lack of QC + bad design decisions at Emco. But I digress. Like I mentioned, I searched all over the web for months looking to find references/solutions/modifications/etc. which would address the problem to no avail. While searching for a solution to making a new set of gibs, a member of that forum revealed the origin of the problem.
... burring at the bolt holes and a bit of dressing ...
The problem is actually twofold in origin: on one hand the plastic glass filled gibs (a contentious issue) and on the other the excess material present on the mating surface where the gibs sit. The new set of brass gibs was a start and the iterative process of dressing/adjusting their mating surfaces to get the right height made a world of difference. I was, as you can imagine, scared shitless (cue Stephen Stills/Woostock/1969) but reasoning it out in detail it quickly became clear to me that, even with a new set of gibs, if they did not run at the right height with respect to the guide rails there was no way I was ever going to be able to get it working properly. ie: the carriage would always have vertical movement. As the U3 carriage is made of Zamak, it has very little mass and the only way to keep it in place/down is via a properly adjusted set of gibs.? Best, JHM
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Hello JHM, thanks for that and for the link to the post on ME. I’m glad I’m not the only one to notice the issue.
I did find some burring at the bolt holes and a bit of dressing with a hand countersink has helped a little I think.
I’m still going to make more of a gib type arrangement (when I get round to it :-) with oilon replacement strips of the same dimensions as the originals, and brass strips above them threaded to take grub screws to apply pressure to the oilon ones below.
I’m keen to use a non-destructive solution, and certainly wouldn’t be filing the saddle. My ham-fisted incompetence could make things considerably worse !
Cheers,
Peter
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I have a rolling tool cart from HF, and bought belts for the Unimat there, but otherwise do my best to avoid; they require a drivers license to return something, and I'm don't steal inventory from stores.? They are not getting my Drivers License and scanning it, it won't take long, and they will get hacked, like everyone else, (Banks, Hospitals, Governments, Insurance Companies, etc, etc.)
HF does have the third hands there and I have purchased for gifts for friends though and they are less expensive at HF then buying at Micromark.
I bought a pair very similar to DIKAKO digital Calipers from Amazon, perhaps 6-7 years ago?? ? I think mine say AIKER on them, but they look like the exact same pair; mine takes a single battery and it easily unscrews with an included screw driver, the battery is the same one as my car remote starter / key fob.? I just replaced the battery yesterday.
Tamra
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Re: Off Topic measuring units
Hello
Dick:
I
invite you and all the Unimat folks to visit my shop and
railroad. I really enjoy sharing.
Carl.
Here is
the railroad and a glimpse of the shop:
Charleston, South Carolina, USA
On 9/16/2023 8:55 AM, OldToolmaker via
groups.io wrote:
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Hello Carl,
I agree and that is how I operate in my home shop today. I am
completely happy with that.
Dick
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Just trying to think of a room in the house I don't have a vernier calliper in -oh yes, the bathroom.?
Sent from
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Re: Off Topic measuring units
The core imperial / standard units really are not that weird. Sure not as neat and tidy as metric with its base 10, but really not hard to work with.
Most of the really out there units are very industry specific, hogsheads, bushels, ffurlongs etc, and they are only weird out of context. If you were a 19th century winemaker then Horseheads would seem perfectly reasonable.
Metric is less flexible resulting in its own need to adapt non-metric units in specific cases such as the French system for medical catheters or gauge system for needles.
Don't even get me started on Celsius which in no way follows the rule of 10 of the metric system and is just as arbitrary as ferenheit only using other numbers.
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Re: Off Topic measuring units
I have a Mitutoyo dial caliper. School threw it out because someone left it in one of the CNC machines, and it froze.?
I hosed it down with WD-40, let it sit for a week or so, with periodic dowsing in more WD-40. When I could get it to move again, I ran strips of paper under the head. Pulled out a bunch of rust. Resprayed, and repeated until no more rust was coming out on the paper. It is the most accurate and easiest to use of all my calipers. I did have to spend something like $7 to buy a new dial lock for it. :)
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Saturday, September 16, 2023 at 08:25:36 AM CDT, Andrei <calciu1@...> wrote:
Calipers and micrometers are a dime a dozen. I have both metric and imperial. They are either dial or digital mechanical (no screwing around with batteries). I also have some conventional but seldom use them anymore.
I do have one of each in electronic digital. One is Starrett and one Mitutoyo and I got them second hand for less than 50 bucks each.
Don't let the perceived cost put you off. Calipers and micrometers do not hold value and can be sourced cheaply.
Get
Hello Carl,
The only metric measuring tools ?I have are my 2 digital calipers. All my other measuring tools (micrometers etc are imperial. At 75 years old I am not about to invest in new tools for hobby use. Manual conversion is quick.
Dick
--
http://www.homemadetools.net/ forum/?OFF- SET-tailstock-center-65965#post105972
?SMALL
TURRET TOOL POST PLANS?
?LARGE
TURRET TOOL POST PLANS
?MINI- LATHE
CARRIAGE LOCK PLANS
?SMALL
QC TOOL POST PLANS?
?QUICK
CHANGE LATHE TURRET
?MINI
LATHE COMPOUND PIVOT MODIFICATION
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Re: Off Topic measuring units
Calipers and micrometers are a dime a dozen. I have both metric and imperial. They are either dial or digital mechanical (no screwing around with batteries). I also have some conventional but seldom use them anymore.
I do have one of each in electronic digital. One is Starrett and one Mitutoyo and I got them second hand for less than 50 bucks each.
Don't let the perceived cost put you off. Calipers and micrometers do not hold value and can be sourced cheaply.
Get
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Show quoted text
Hello Carl,
The only metric measuring tools ?I have are my 2 digital calipers. All my other measuring tools (micrometers etc are imperial. At 75 years old I am not about to invest in new tools for hobby use. Manual conversion is quick.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL
TURRET TOOL POST PLANS?
?LARGE
TURRET TOOL POST PLANS
?MINI-LATHE
CARRIAGE LOCK PLANS
?SMALL
QC TOOL POST PLANS?
?QUICK
CHANGE LATHE TURRET
?MINI
LATHE COMPOUND PIVOT MODIFICATION
|
Re: Off Topic measuring units
Hello Carl,
The only metric measuring tools ?I have are my 2 digital calipers. All my other measuring tools (micrometers etc are imperial. At 75 years old I am not about to invest in new tools for hobby use. Manual conversion is quick.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
|
Re: Off Topic measuring units
Hello Carl,
I agree and that is how I operate in my home shop today. I am completely happy with that.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
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“ I generally have a pair on our Dining Room table so I can measure something quickly.”.
“No pudding until you eat up all your greens!” “Half?, please”, “ok half”. “Can I have pudding now?”
“That’s not half!” “Yes it is!”
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On 16 Sep 2023, at 04:09, Tamra <tamrabrogdon@...> wrote:
I generally have a pair on our Dining Room table so I can measure something quickly.
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Re: What is the 'BEST' Unimat ?
You’re welcome Pat.? As a science major I got used to the metric system in high school (early 1960s) as almost every class I had drilled us on using the metric system and doing conversions.? As calculators were rare (and expensive), they were not allowed in class so everything had to be done on a slide rule.? When students complained, one of my teachers used to tell them, “Come on now.? It’s as easy a falling off a log.”? Most in the class never got the pun. ? When I was a grad student in radiological sciences (which was health physics and some medical physics) I missed my chance to take the reactor operator class (we had a small Triga reactor in the basement of the physics building) .? Instead, the department chair dropped me and another student into the first two quarters of medical school, which likely did me more good as a health physicist..? ?? ? Jerry F. ?? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of pat goodyear
Sent: Friday, September 15, 2023 10:49 AM
To: Gerald Feldman; [email protected]
Subject: Re: [Unimat] What is the 'BEST' Unimat ?? Jerry; you popped a memory bubble.? ?Back in Naval Nuclear Power School (1974) in order to grasp unit conversions, we had all sorts of goofy conversions to do.? One was to convert furlongs per fortnight to inches per second, to mm per second .....? ?As? some of our calculations dealing with forces inside a reactor at power could be mind numbing.? ? Anyhow thanks for the blast from the past.? ?
Pat
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My only digital caliper is a Harbor Freight unit that I've been fighting with for about 6 years.? It would reset to zero randomly due to bad battery connections.? I finally figured out how to make it reliable, and it's actually not that bad.? I do like using it convert units, sort drill bits, etc.? (I also have 5 or 6 "real" dial calipers like B&S, Tesa, etc, but my goto is an Enco I got in '86 that gets abused, but has never failed me)
-Dave
On Friday, September 15, 2023 at 08:09:34 PM PDT, Tamra <tamrabrogdon@...> wrote:
I truly appreciate Dial Calipers...
When I attend classes, I take a pair of dial calipers and the digital dial calipers that convert to mm at touch of a button, they are truly useful, and I generally have a pair on our Dining Room table so I can measure something quickly.
In terms of doing projects on a metal lathe, I think it is very, very useful to have 2 pairs.? One pair measures the diameter, and 1 pair measures the length... this has been very helpful when I'm making duplicate parts.??
Tamra
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I truly appreciate Dial Calipers...
When I attend classes, I take a pair of dial calipers and the digital dial calipers that convert to mm at touch of a button, they are truly useful, and I generally have a pair on our Dining Room table so I can measure something quickly.
In terms of doing projects on a metal lathe, I think it is very, very useful to have 2 pairs.? One pair measures the diameter, and 1 pair measures the length... this has been very helpful when I'm making duplicate parts.??
Tamra
|
Re: Off Topic measuring units
Hello
Dick:
I think
the biggest problem with the metric conversion ( changing our
standards ) that they focused on metric conversions (
calculations of conversions of values from imperial to metric
) with all the odd ratios. If they had focused more on the
simplicity of working in metric and the idea of abandoning old
standards ( Letter, Fraction and Number drill sizes, etc. ) it
might have flown. As it is metric is all around us and we are
mostly using imperial for home projects.
Carl.
On 9/15/2023 8:29 PM, OldToolmaker via
groups.io wrote:
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I remember back in the fifties,sixtys and seventies the US was
actively attempting to adopt the metric system and had a plan to
accomplish same. However, the US could not muster up enough
support from various industry factions to maintain traction. The
auto industry and others bucked and consequently the attempt
failed big time due to conversion costs. Somehow I lived through
it all and only have a few scars to show for it. I had forgotten
the debacle entirely until this discussion awakened my memory.
Dick
--
forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST
PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE
LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT
MODIFICATION
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Re: Off Topic measuring units
I wouldn’t worry too much about which system is “better”, when you consider that ALL of the units we use for length, mass, or time are variables and change with one’s velocity.? The effects of Einstein’s special theory of relativity are not easily ?observed at slower velocities, but as one starts to approach the speed of light, time slows down, mass increases, ?and distance shrinks when they are observed from an outside frame of reference.? The reason that our GPS system works as well as it does is because we are able to predict what happens to time in the satellite clocks as they circle the earth and compensate for the changes.? ? Jerry F. ????? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Martin P. via groups.io
Sent: Friday, September 15, 2023 8:58 AM
To: [email protected]
Subject: Re: [Unimat] Off Topic measuring units? I will readily admit the Metric system (Actually S.I.) is more logical and calculation-friendly. I grew up with U.S. Customary, so that is most natural for me. That said, I do like the color (colour) of U.S./Imperial system. The foot was originally supposed based an English king's foot. Someone here knows which one. The mile is from Latin mille, 1000. Originally 1000 Roman long paces (about 5'). IOW, based on something tangible. The meter was like that originally, one ten-millionth of the distance from the to the along a . Redefined several times into something arbitrary. Which adds another wrinkle to U.S. Customary. Now we have two different feet, the common or officially the International Foot, which is based on a metric conversion. The U.S. Survey Foot, which corresponds to the original foot used in historical surveys. (1 FTUS = 1.000002 FT) It can make a significant difference when using State Plane Coordinates, which here in Florida the Northings and Eastings run into six digits left of the decimal. On Thursday, September 14, 2023 at 09:23:02 PM EDT, Gerald Feldman <gfeldman2904@...> wrote: Metric rocks <snip> furlongs per fortnight. ? Jerry F. ? ? ? ?
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Re: Off Topic measuring units
I remember back in the fifties,sixtys and seventies the US was actively attempting to adopt the metric system and had a plan to accomplish same. However, the US could not muster up enough support from various industry factions to maintain traction. The auto industry and others bucked and consequently the attempt failed big time due to conversion costs. Somehow I lived through it all and only have a few scars to show for it. I had forgotten the debacle entirely until this discussion awakened my memory.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
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Hi
Gang:
For
real fun Pattern Shops use "shrink scales", to build wooden
patterns for sand casting iron or aluminum. They are a certain
percentage over sized so when the metal cools it is the
desired size.
For fun
the old timers would slip the shrink scale to an apprentice
and watch as he cut stock over sized, etc.
The one
mile that makes sense to me is the Nautical Mile, it equals 1
minute of distance at the equator of the earth. Handy for
navigation, on the seas and also in space??
Carl.
On 9/15/2023 1:13 PM, Dave Seiter
wrote:
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I have a couple of Brown
& Sharpe 6" rules that have tenths and hundredths on one
side.? One has 32nds and 64ths on the reverse, but the other
is blank.? I don't know how many times I've picked up the
blank one wanting to use the fractional scale and ended up
estimating using 10ths scale.? When I took drafting and
architectural drawing in high school, we had one drafting
table out of the 30 or so in the class where all the scales
were 1/10 and 1/00.? It was rarely used.?
-Dave
On Friday, September 15, 2023 at 07:43:06 AM PDT, Martin
P. via groups.io <mdupreno1@...> wrote:
As an engineer working with land
surveys and building design, I routinely use 10ths
and 100ths of a foot, as well as feet and inches and
fractions.
As a shooting aficionado, I am used to
caliber (100ths of an inch), and millimeters. So I
have no problem visualizing dimensions in any of
these.
On Thursday, September 14, 2023 at 02:03:04 PM
EDT, Peter Brooks <peter@...>
wrote:
You engineering types have all been decimal
for years… tenths, hundredths, thous…
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Re: Mensuration, was Re: [Unimat] What is the 'BEST' Unimat ?
Yes, the metrification of plywood drives me nuts!? At least the other dimensions are correct.? Another change is the length and width of 5mm (3/16") luan; it used to be exactly 4x8', but now I always check because sometimes it's accurate, most of the time it's about 1/8-3/16" too long, and sometimes both length and width are too big.? I think it depends on the country of origin.?
-Dave
On Friday, September 15, 2023 at 11:07:47 AM PDT, pat goodyear <pgoodyear@...> wrote:
So now that you mention it a 4x8 sheet of plywood from the local Home Depot is not 3/4" thick it is 19mm which really screws up projects when you come out off a 32 or 64.? Pain in the Axx if you ask me.? ? I have engineering rulers graduated in 10ths, 12ths, 16ths, 32nds, and in metric also they have scales that adjust to divisions or multiples thereof.? I bought them years ago for scaling projects to size..? ?They come in quite handy when I need them.? ?
pat
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Tamra
Carl
Bill in OKC too
OldToolmaker