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suspension spring mounting holes

Carroll Hardin

Registered User
Jul 24, 2001
314
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hi all,
I have read many times here that there are no stupid questions for help, so here goes;
The white metal which the suspension springs are made of now is so hard, it is difficult to ream the pin holes for installing without destroying the unit. If not held tight enough-the unit will twist and ruin-if held too tight, the top chops will come apart. All of you except me has probably devised a jig or system for doing this. Would you share your method? Thanks

Carroll
 

Carroll Hardin

Registered User
Jul 24, 2001
314
1
0
hi all,
I have read many times here that there are no stupid questions for help, so here goes;
The white metal which the suspension springs are made of now is so hard, it is difficult to ream the pin holes for installing without destroying the unit. If not held tight enough-the unit will twist and ruin-if held too tight, the top chops will come apart. All of you except me has probably devised a jig or system for doing this. Would you share your method? Thanks

Carroll
 

LaBounty

NAWCC Life Member
NAWCC Member
Aug 29, 2002
3,455
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Mitchell, NE
www.abouttime-clockmaking.com
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Hey Carroll-

This is a common pain when having to make the hole larger in top of the suspension unit in order to accommodate the thumb screw. What I use is a tapered reamer or cutting broach, making the hole larger by hand. But over time, the process will destroy the cutting broach so I use one which is at the end of its usefulness.

I haven't looked lately, but I think that style of suspension unit is being made with a larger hole...If we are talking about the same one. :)

Something else to consider...If you've dulled the drill bit you are using, that could be the problem and not the steel. Try a new one, with cutting fluid, and just enough pressure so it cuts. Too much pressure heats up the bit causing it to burn and become dull.

Good luck with it!
 

Carroll Hardin

Registered User
Jul 24, 2001
314
1
0
Thanks gvasale and David.
I just received a dozen of the suspension spring mentioned and the hole is still smsll.
My question was how to hold that sucker to ream the hole without destroying the unit. hold it too loosely and it wil twist into a pretzel when the reamer catches. Hold it too tightly and the chops will come apart, ruing the unit. Wish they would go back to the plastic which didn't cause that problem.

Carroll
 

gvasale

NAWCC Member
Mar 30, 2005
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webster, Ma
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Carroll: you still haven't said as far as I can tell what kind of suspension spring it is. Do you have a really good hand vise? And a pin vise too? How about some number wire drills?
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
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Whitby, Ontario, Canada
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Hi Carroll. I assume you are referring to Hermle type movement suspension springs. I use a small vice to hold it and ream it out by hand. Takes 5 minutes or so. I use the cutting broaches in my Bergeron set. Just don't apply too much pressure downward. Harold
 

Carroll Hardin

Registered User
Jul 24, 2001
314
1
0
Hi qva

I am referring to the type used on hermle,etc.
maybe i got a bad batch, but have had two of them come apart while gripping to ream out the holes, which is the worst problem.

Thanks to Harold also. Oh, for the brass chops or even the plastic ones. Such a little thing to cause such large problems.

Carroll
 

Carroll Hardin

Registered User
Jul 24, 2001
314
1
0
Thanks David,
Your idea is a good one, and should be great for the feather type suspension spring. Just might rig it to hold for drilling or reaming the pin hole in a hermle type.

Carroll
 

Denis O Jahn

NAWCC Member
Aug 28, 2000
264
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16
Visalia, CA.
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Carroll: Ive had success drilling the holes to a larger size. I place the spring on a piece of soft wood (pine) and grip the top block on the sides with long-nose pliers. I use a Dremmel flexable shaft, low RPM. The only problem is you need to file the back side to remove the burrs. Ive taken a strip of brass that is thinner than the top chops and secured it to the same block of wood to act as a stop for the top chops, to file against. It helps if you have a hole for the bottom chops pin to fit into.
I found when using reamers or broachs, I had to grip the top chop so tight, to keep it from turning, I was destroying about half of the units before I got a chance to break the spring portion:> Not to mention the abuse the broach was getting.
 

Carroll Hardin

Registered User
Jul 24, 2001
314
1
0
Denis,

I'll try your methods. This seems to be a new problem for me, one I've not had until recently......The met in these thins seem to be harder than necessary and the chops are put together with shallow dimples. We deserve better than this.

Carroll
 

wilf

Registered User
Apr 16, 2002
92
0
0
Hi carroll. the way i have been doing it is.
I use a stacking block with various size holes.
I select the hole closest to hole required and a punch with a flat head , make sure the punch head enters the hole in the block approximately 1/2mm,or less, line up the suspension spring in line with the punch head and hole in the block, with a small hammer give it a dry wack.
Works for me.
 

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