Tapered Dowel Pins

[Harry WilkesParticipant @harrywilkes58467]

[Harry WilkesParticipant @harrywilkes58467]

Hi Guy's

I need to make a couple of tapered dowel pins which I understand are 1:48 but can anyone advise me what angle I would need to set my cross slide ?

Thanks

H

[Capstan SpeakingParticipant @capstanspeaking95294]

It's 0.595 degrees.

I'd just buy a pack.

[KWILParticipant @kwil]

1 :48 taper, tan setover = 1/48. ….1.19 degrees. good luck. Much easier to buy them

[Capstan SpeakingParticipant @capstanspeaking95294]

Harry asked what the offset was. You've given the included angle.

[Keith LongParticipant @keithlong89920]

Just for the record, if the taper dowels are METRIC then the standard included taper is 1:50 not 1:48 which is for IMPERIAL

[Neil WyattModerator @neilwyatt]

> Just for the record, if the taper dowels are METRIC then the standard included taper is 1:50 not 1:48 which is for IMPERIAL

Use brass pins and an 'ammer.

Neil

[Harry WilkesParticipant @harrywilkes58467]

Posted by Capstan Speaking on 16/06/2015 16:15:32:

It's 0.595 degrees.

I'd just buy a pack.

Many thanks to all for the info, Capstan Speaking if you can tell me where I can by a pack of 5/32 I'd certainly buy them ! I have checked out several website thrown up by google but 5/32 seem's to be the illusive size

Cheers H

[VicParticipant @vic]

http://www.boneham.co.uk/resources/Dowel%20Pins%20and%20Clevis%20Pins.pdf

[Bob Brown 1Participant @bobbrown1]

or here **LINK**

[stan pearson 1Participant @stanpearson1]

Hello H

Reeves sell them 5/32" x 1" long

Stan

[Harry WilkesParticipant @harrywilkes58467]

Thanks again guy's

Cheers H

[LambtonParticipant @lambton]

You will need a taper reamer for preparing the hole. Drill it first to the small end diameter of the pin then carefully ream until the pin engages properly.

[Harry WilkesParticipant @harrywilkes58467]

Posted by Bob Brown 1 on 16/06/2015 22:14:51:

or here **LINK**

Wow £6.95 for a pack of 5 and wait for it £6.50 P&P

H

[Clive HartlandParticipant @clivehartland94829]

The modern method now is, 'Roll Pins'. most of the new kit coming in has roll pins on shafts if they have to lock things to the shafts. makes servicing much easier as you do not have to hammer seven bells out of something to get a taper pin out.

Clive

[julian atkinsParticipant @julianatkins58923]

hi harry,

if you pm me i will send you a couple.

cheers,

julian

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Harry Wilkes on 17/06/2015 05:15:48:

Posted by Bob Brown 1 on 16/06/2015 22:14:51:

or here **LINK**

Wow £6.95 for a pack of 5 and wait for it £6.50 P&P

H

.

Harry,

It looks like your opening question was the right one to ask !!

What I don't think you have told us is whether the tapered holes already exist.

i.e. are you making something, or refurbishing it ?

This is significant because, as mentioned by others; you need a tapered hole for a taper pin.

If the hole already exists, you need to measure it carefully … and if not, you will need a reamer.

Given the close similarity between 5/32" x 2" 1:48 and 4mm x 50mm 1:50 … be very careful to check what people are trying to sell you.

If you have the reamer, it's best to put it in the lathe and set the top-slide to match its taper.

If you don't have the reamer, then you could make a D-bit version from Silver Steel, and turn it and the Pins at the same top-slide setting.

Of course; Clive's roll-pins have merit in the appropriate situation.

MichaelG.

.

Edit: … or you might hit lucky, and find a nice chap like Julian

Edited By Michael Gilligan on 17/06/2015 08:41:13

[AjohnwParticipant @ajohnw51620]

I noticed rather a long time ago that plastic moulding tools for battery cases were not dowelled any more and used roll pins and asked about it as given the size of the chunks of steel and the location needed it surprised me. It seems that roll pins are sized so that smaller ones can be knocked into larger ones. That's what they were doing. This must be at least 15 years ago.

Tapered pins have the advantage that precise diameters are not needed only a fairly precise taper. Roll pins are designed to be driven into drilled holes.

John

–

Edited By John W1 on 17/06/2015 09:51:57

[Harry WilkesParticipant @harrywilkes58467]

Posted by julian atkins on 17/06/2015 08:24:03:

hi harry,

if you pm me i will send you a couple.

cheers,

julian

Julian many thanks for your kind offer will PM you, Michael yes I have a tapered reamed hole ready for the the dowel !

Cheers H

[Harry WilkesParticipant @harrywilkes58467]

Just to fill you guy's in where the piston rod is fitted into the crosshead on my traction engine a tapered dowel pins is used it should be a small tapered wedge but in my case it's a dowel. The one I fitted last time was very tight when I came to remove it and I damaged getting it out I will sometime in the future make and fit the small tapered wedge.

Cheers H

Posted by Michael Gilligan on 17/06/2015 08:39:08:

Posted by Harry Wilkes on 17/06/2015 05:15:48:

Posted by Bob Brown 1 on 16/06/2015 22:14:51:

or here **LINK**

Wow £6.95 for a pack of 5 and wait for it £6.50 P&P

H

.

Harry,

It looks like your opening question was the right one to ask !!

What I don't think you have told us is whether the tapered holes already exist.

i.e. are you making something, or refurbishing it ?

This is significant because, as mentioned by others; you need a tapered hole for a taper pin.

If the hole already exists, you need to measure it carefully … and if not, you will need a reamer.

Given the close similarity between 5/32" x 2" 1:48 and 4mm x 50mm 1:50 … be very careful to check what people are trying to sell you.

If you have the reamer, it's best to put it in the lathe and set the top-slide to match its taper.

If you don't have the reamer, then you could make a D-bit version from Silver Steel, and turn it and the Pins at the same top-slide setting.

Of course; Clive's roll-pins have merit in the appropriate situation.

MichaelG.

.

Edit: … or you might hit lucky, and find a nice chap like Julian

Edited By Michael Gilligan on 17/06/2015 08:41:13

[Paul LousickParticipant @paullousick59116]

Machinists Workshop just posted some info about taper pins:

Taper Pin Tips

By David Winkel

I’m sure most of us have had to deal with removing taper pins in machinery that were driven home by a gorilla with a 10 pound hammer.

After driving one of these stubborn pins out, do yourself, or the next guy, a favor and coat the new pin with a thin film of Moly Sulfide grease. Tap it home until seated, but no more!

Pins are sized by the large end diameter and you need to measure the large end hole diameter to determine the proper size replacement to use. Often the lip of the hole will be munged so you should measure the hole down a little deeper.

Here’s a trick: choose a burr-free drill shank with a diameter that allows it to go down the hole perhaps 1/8” or so. Measure the insertion depth and call it “D.” Mic the shank diameter and call it “d.”

A pin’s standard taper is 1/4”/foot or 1/48”/inch. So, the big end hole diameter will be

D/48 + d

One final trick is to make the pin slightly shorter so the small end is recessed in a pocket about 1/16” deep when driven home. That will keep the drive-out pin punch centered for easier removal by the next guy.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Paul Lousick on 17/06/2015 23:05:22:

One final trick is to make the pin slightly shorter so the small end is recessed in a pocket about 1/16” deep when driven home. That will keep the drive-out pin punch centered for easier removal by the next guy.

.

Excellent idea … it also avoids the risk of:

1. corrosion increasing the diameter of the small end
2. heavy hammering bruising the small end

MichaelG.

[Harry WilkesParticipant @harrywilkes58467]

Just like to say a public 'thank you' to Julian for his kindness in sending me some dowels.

Big thanks Julian

H

[mark costello 1Participant @markcostello1]

Great idea, never seen that done.

[alan smith 6Participant @alansmith6]

Regarding Paul`s posting, leaving the small end of the pin recessed is a good idea but not if you are going to submit your model to a competition.

The way I was taught at Matrix was to ream the hole then lightly tap in the over length pin, cut it to length leaving about 1/16" proud at either end. Tap out the pin and dome and polish the ends in a lathe. This will make a more aesthetically pleasing result and an easily removeable pin.

One terrible experience that I had with taper pins was on a vintage car engine where the starting handle dog was splined and pinned to the starting handle. The clown that had assembled it had cut off the pin ends and polished the assembly so that the ends of the pins were not visible. There was a casting between the handle and the dog which prevented me from shearing off the pin by axial force and even heating up the dog did not reveal the pin ends! This was a rush job and I ended up sawing off the dog leaving a little of the handle diameter with it, chucking it in the lathe and by taking a light cut I was able to reveal the pin, remove it , detach the dog and welded the splined section back onto the shaft.

The moral, of course, is to always leave a portion of the pin proud of the shaft, even if you cannot drive out the pin easily then centre punch the end and drill it out. If it`s possible to heat the shaft, do this quickly to stop the assembly expanding evenly, spray on some WD40 and the pin should come out. Drilling is the last resort.

Alan

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